U.S. patent application number 12/373753 was filed with the patent office on 2009-10-22 for composition for filtering and removing particles and/or constituents from a fluid.
This patent application is currently assigned to World Minerals Inc.. Invention is credited to Qingchun Hu, Niels S. Mastrup, George A. Nyamekye, Walter N. Pavlakovich, Robert H. Rees, Larisa Tihomirov.
Application Number | 20090261041 12/373753 |
Document ID | / |
Family ID | 38924215 |
Filed Date | 2009-10-22 |
United States Patent
Application |
20090261041 |
Kind Code |
A1 |
Hu; Qingchun ; et
al. |
October 22, 2009 |
Composition for Filtering and Removing Particles and/or
Constituents from a Fluid
Abstract
Filter-aid materials are disclosed herein, and processes,
systems, and methods using such filter-aid materials for filtering
and removing particles and/or constituents from a fluid, wherein
the filter-aid material comprises at least one filterable composite
adsorbent comprising at least one adsorbent component formed
in-situ on at least one filtration component. Further disclosed
herein are filter-aid materials and processes, systems, and methods
using such filter-aid materials for filtering and removing
particles and/or constituents from a fluid, wherein the filter-aid
material comprises at least one filterable composite adsorbent
comprising at least one adsorbent component formed in-situ on at
least one filtration component, and wherein the filter-aid material
further comprises an at least one additional filtration component
mixed with the at least one filterable composite adsorbent.
Inventors: |
Hu; Qingchun; (Lompoc,
CA) ; Nyamekye; George A.; (Snowflake, AZ) ;
Rees; Robert H.; (Santa Maria, CA) ; Mastrup; Niels
S.; (Santa Maria, CA) ; Tihomirov; Larisa;
(Lompoc, CA) ; Pavlakovich; Walter N.; (Santa
Maria, CA) |
Correspondence
Address: |
FINNEGAN, HENDERSON, FARABOW, GARRETT & DUNNER;LLP
901 NEW YORK AVENUE, NW
WASHINGTON
DC
20001-4413
US
|
Assignee: |
World Minerals Inc.
Santa Barbara
CA
|
Family ID: |
38924215 |
Appl. No.: |
12/373753 |
Filed: |
July 13, 2007 |
PCT Filed: |
July 13, 2007 |
PCT NO: |
PCT/US07/73439 |
371 Date: |
January 14, 2009 |
Related U.S. Patent Documents
|
|
|
|
|
|
Application
Number |
Filing Date |
Patent Number |
|
|
60830781 |
Jul 14, 2006 |
|
|
|
60945954 |
Jun 25, 2007 |
|
|
|
Current U.S.
Class: |
210/665 ;
210/193 |
Current CPC
Class: |
B01D 37/025 20130101;
C02F 2303/20 20130101; C12H 1/063 20130101; C02F 1/288 20130101;
B01D 39/2068 20130101; C02F 1/28 20130101; C02F 2209/11 20130101;
C02F 1/281 20130101; B01D 2239/0478 20130101; B01D 2239/1291
20130101; C02F 1/286 20130101 |
Class at
Publication: |
210/665 ;
210/193 |
International
Class: |
B01D 37/02 20060101
B01D037/02 |
Claims
1: A filter-aid material for absorbing particles and/or
constituents from a fluid comprising: at least one filterable
composite adsorbent comprising at least one filtration component
and at least one adsorption component formed in-situ on a surface
of the at least one filtration component, wherein the at least one
adsorbent component comprises less than about 40% by weight of the
filter-aid material and the at least one adsorbent component has an
average particle size of less than about 1 micrometer.
2-3. (canceled)
4: The filter-aid material according to claim 1, wherein the at
least one filtration component is chosen from biogenic silicas,
natural glasses, buoyant glasses, buoyant polymers, cellulose,
silicates, alumina, and mixtures thereof.
5: The filter-aid material according to claim 1, wherein the at
least one filtration component is diatomite.
6: The filter-aid material according to claim 1, wherein the at
least one filtration component is perlite.
7: The filter-aid material according to claim 1, wherein the at
least one adsorbent component is a silica gel.
8: The filter-aid material according to claim 1, wherein the at
least one adsorbent component comprises at least about 5% by weight
of the filterable composite adsorbent.
9. (canceled)
10: The filter-aid material according to claim 8, wherein the at
least one adsorbent component comprises at least about 10% by
weight of the filterable composite adsorbent.
11. (canceled)
12: The filter-aid material according to claim 1, wherein the
average particle size of the adsorbent component is less than about
0.5 microns.
13: The filter-aid material according to claim 1, wherein the
average particle size of the adsorbent component is less than about
0.1 microns.
14. (canceled)
15: The filter-aid material according to claim 1, wherein the BET
surface area of the at least one adsorbent component ranges from
about 25 to about 2550 m.sup.2/g.
16: The filter-aid material according to claim 15, wherein the BET
surface area of the at least one adsorbent component ranges from
about 50 to about 500 m.sup.2/g.
17-19. (canceled)
20: The filter-aid material according to claim 1, wherein the
average permeability of the filtration adsorbent composite ranges
from about 0.05 to about 10 Darcy.
21. (canceled)
22: The filter-aid material according to claim 1, having a wet
density ranging from about 10 to about 25 lb/ft.sup.3.
23. (canceled)
24: A filter-aid material for absorbing particles and/or
constituents from a fluid comprising: at least one filterable
composite adsorbent comprising at least one filtration component
and at least one adsorption component formed in-situ on a surface
of the at least one filtration component, wherein the at least one
adsorbent component has an average particle size of less than about
1 micrometer; and an at least one additional filtration component
mixed with the at least one filterable composite adsorbent, wherein
the at least one adsorbent component comprises less than about 40%
by weight of the filter-aid material.
25-27. (canceled)
28: The filter-aid material according to claim 24, wherein the at
least one filtration component is diatomite.
29: The filter-aid material according to claim 24, wherein the at
least one filtration component is perlite.
30: The filter-aid material according to claim 24, wherein the at
least one adsorbent component is a silica gel.
31-63. (canceled)
64: A method for removing particles and/or constituents in a fluid,
comprising: (i) providing a filter-aid material comprising an at
least one filterable composite adsorbent comprising at least one
filtration component; and at least one adsorption component formed
in-situ on the surface of the at least one filtration component;
wherein the at least one adsorbent component comprises less than
about 40% by weight of the filter-aid material and the at least one
adsorbent component has an average particle size of less than about
1 micrometer; (ii) pre-coating a filter element with the filterable
composite adsorbent; and (iii) passing a fluid containing particles
and/or constituents to be adsorbed through the coated filter
element.
65-73. (canceled)
74: The method according to claim 64, wherein the at least one
filtration component is chosen from biogenic silicas, natural
glasses, buoyant glasses, buoyant polymers, cellulose, silicates,
aluminas, and mixtures thereof.
75: The method according to claim 64, wherein the at least one
adsorbent component is a silica gel.
76-89. (canceled)
90: A method for removing particles and/or constituents from a
fluid, comprising: precoating a filter element with the filter-aid
material of claim 1; and passing a fluid containing particles
and/or constituents to be removed through the precoated filter
element.
Description
RELATED APPLICATIONS
[0001] This application incorporates by reference in their
entireties U.S. Provisional Application Nos. 60/830,781 filed Jul.
14, 2006, and 60/945,954 filed Jun. 25, 2007.
FIELD OF THE INVENTION
[0002] Disclosed herein are filter-aid materials and processes,
systems, and methods using such filter-aid materials for filtering
and removing particles and/or constituents from a fluid, wherein
the filter-aid material comprises at least one filterable composite
adsorbent comprising at least one adsorbent component formed
in-situ on at least one filtration component. Also disclosed herein
are filter-aid materials and processes, systems, and methods using
such filter-aid materials for filtering and removing particles
and/or constituents from a fluid, wherein the filter-aid material
comprises at least one filterable composite adsorbent comprising at
least one filtration component (such as a siliceous material) and
at least one adsorbent component (such as a precipitated silica
gel) having an average particle size of less than about 1 micron.
Also disclosed herein are the filter-aid materials described above,
wherein the filter-aid material further comprises at least one
additional filtration component.
BACKGROUND OF THE INVENTION
[0003] In many filtration applications, a filtration device is
comprised of both a filter element, such as a septum, and a
filter-aid material. The filter element may be of any form such
that it may support a filter-aid material, for example a
cylindrical tube or wafer-like structure covered with a plastic or
metal fabric of sufficiently fine weave. The filter element may be
a porous structure with a filter element void to allow material of
a certain size to pass through the filtration device. The
filter-aid material may comprise one or more filtration components,
which for example may be inorganic powders or organic fibrous
materials. Such a filter-aid material may be used in combination
with a filter element to enhance filtration performance. Often,
filtration components for use in a filter-aid material are
comprised of such materials as diatomite, perlite, and cellulose.
As an example illustrative of the field of filtration, the
filter-aid material may initially be applied to the septum in a
process known as "pre-coating." Pre-coating generally involves
mixing a slurry of water and filter-aid material and introducing
the slurry in a stream flowing through the septum. During this
process, a thin layer, such as about 1.5 mm to about 3.0 mm, of
filter-aid material will eventually be deposited upon the septum,
thus forming the filtration device.
[0004] During the filtration of a fluid, various insoluble
particles in the fluid are trapped by the filter-aid material. The
combined layers of filter-aid material and particles and/or
constituents to be removed accumulate on the surface of the septum.
Those combined layers are known as "filter cake." As more and more
particles and/or constituents are deposited on the filter cake, the
filter cake may become saturated with debris to the point where
fluid is no longer able to pass through the septum. To combat that
problem, a process known as "body feeding" is often used. Body
feeding is the process of introducing additional filter-aid
material into the fluid to be filtered before the fluid reaches the
filter cake. The filter-aid material will follow the path of the
unfiltered fluid and will eventually reach the filter cake. Upon
reaching the filter cake, the added filter-aid material will bind
to the cake much the same way the filter-aid material bound to the
septum during the pre-coating process. That additional layer of
filter-aid material causes the filter cake to swell and thicken and
increases the capacity of the cake to entrap additional debris.
[0005] As mentioned above, in the field of fluid filtration many
methods of particle separation employ, for example, materials
chosen from diatomite materials, expanded perlite, natural glasses,
and cellulose materials as porous filtration components. Those
materials have intricate and porous structures that may be
particularly suited to the effective physical entrapment of
particles in filtration processes. Those intricate and porous
structures create networks of void spaces that may result in
buoyant filtration media particles that have apparent densities
similar to those of the fluids in which they are suspended. It is
common practice to employ porous filtration components when
improving the clarity of fluids. The porous filtration component is
often used to remove undesired particles or constituents such as
particulate matter from a fluid. However, while well suited for the
task of removing particulate matter by physical entrapment, those
porous filtration components may not be as well suited for the task
of removing particulate matter from a fluid by the process of
adsorption and are thus often times used in combination with an
adsorbent component.
[0006] Diatomite, perlite, rice-hull ash, and cellulose are some
examples of filtration component materials that may be used for
particle separation. Diatomite, also known as diatomaceous earth,
is a sediment enriched in biogenic silica in the form of siliceous
skeleta of diatoms, a diverse array of microscopic, single-cell
algae. Those frustules are sufficiently durable to retain much of
their microscopic structure through long periods of geological time
and through thermal processing. Diatomite products have an
inherently intricate and porous structure composed primarily of
silica. Perlite is a naturally occurring volcanic glass that may
thermally expand upon processing. The structure of perlite may not
be as intricate as diatomite and, consequently, perlite may be
better suited for separating coarse micro-particulates from liquids
having high solids loading. Finally, cellulose filtration component
materials are generally produced by sulfite or sulfate processing
of hardwoods and/or softwoods. Like perlite, cellulose filtration
component materials may possess a less intricate structure than
diatomite filtration component materials.
[0007] As used herein, "turbidity" is the cloudiness or haziness of
a fluid, where the haze may be caused by individual particles that
are suspended in the fluid. Materials that may cause a fluid to be
turbid include, for example, clay, silt, organic matter, inorganic
matter, and microscopic organisms. Turbidity may be measured by
using an instrument known as a nephelometer that emits a beam of
light through a column of the fluid being tested. A detector
positioned on the same side of the fluid column measures the amount
of light reflected by the fluid. A fluid that contains a relatively
large number of suspended particles will reflect a greater amount
of light than a fluid containing fewer particles. Turbidity
measured in this fashion may be quantified in Nephelometric
Turbidity Units ("NTU"). In addition, Turbidity may also be
measured using gravimetric methods.
[0008] A trade-off typically exists in filter-aid technology
between the permeability of the porous media used as a filtration
component and its turbidity removal capabilities. Filtration
components are produced in grades over a wide range of permeability
ratings. As the permeability of the filtration component decreases,
the ability of the filter-aid material to remove small particles
may increase, but often at the expense of a slower flow rate
through the filter-aid material. Conversely, as the filtration
component permeability increases, the ability of the filter-aid
material to filter particles may decrease and, consequently, the
fluid flow through the filter-aid material increases. The extent to
which this takes place will depend upon the type and particle size
distribution of the suspended particles being removed from the
fluid.
[0009] As used herein, "wet density" is an indicator of a
material's porosity. For example, wet density reflects the void
volume available to entrap particulate matter in a filtration
process and, consequently, wet density may be used to determine
filtration efficiency. Percent porosity may be expressed by the
following formula:
Porosity=100*[1-(wet density/true density)]
[0010] Thus, filtration components with lower wet densities may
result in products with greater porosity, and thus perhaps greater
filtration efficiency, provided that the true density stays
relatively constant. Typical wet densities for common filtration
components may range from at least about 12 lb/ft.sup.3 to about 30
lb/ft.sup.3 or greater.
[0011] As used herein, "adsorption" is the tendency of molecules
from an ambient fluid phase to adhere to the surface of a solid.
This is not to be confused with the term "absorption," which
results when molecules from an ambient fluid diffuse into a solid,
as opposed to adhering to the surface of the solid.
[0012] To achieve a desired adsorptive capacity, and thus to be
practical for commercial use, an adsorbent component may have a
relatively large surface area, which may imply a highly porous
structure with a small adsorbent component particle size. In
certain embodiments, porous adsorbent components, in their
un-reacted powder form, can have surface areas ranging up to
several hundred m.sup.2/g.
[0013] One technique for calculating specific surface area of
physical adsorption molecules is the Brunauer, Emmett, and Teller
("BET") theory. The application of BET theory to a particular
adsorbent component yields a measure of the materials specific
surface area, known as "BET surface area." Generally speaking, BET
surface areas of practical adsorbent components in their un-reacted
powder form may range from about 300 to about 1200 m.sup.2/g. As
used herein, "surface area" refers to BET surface area.
[0014] One method of using an adsorbent component is to place the
adsorbent component in contact with a fluid containing particles
and/or constituents to be adsorbed, either to purify the fluid by
removing the particles and/or constituents, or to isolate the
particles and/or constituents so as to purify them. In certain
embodiments, the adsorbent component containing the adsorbed
particles or constituents is then separated from the fluid, for
example by a conventional filtration process.
[0015] An illustrative example of an adsorption practice may be
seen in the process of beer "chill-proofing." It is currently known
that, unless specially treated, chilled beer may undergo a chemical
reaction that results in the production of insoluble particles. In
that chemical reaction, hydrogen bonds may form between haze-active
proteins and/or polyphenols in a chilled condition. The reacted
proteins and/or polyphenols may then grow to large particles, which
causes the beer to become turbid, a condition also known as
"chill-haze." Chill-haze may be undesirable to both consumers and
brewers. Turbidity may be most pronounced when the beer has been
chilled below room temperature. In certain instances, such as when
the particles are proteins, as the temperature increases, the
hydrogen bonds that hold the proteins together may be broken.
[0016] Chill-proofing may comprise a process that employs at least
one adsorption component and/or at least one filtration component
to remove particles creating chill-haze in the beer. One form of
chill-proofing involves, in one step, adding solid adsorbent
components, such as silica gel, to the beer prior to packaging. The
particles and/or constituents bind to the added adsorbent
components, and then, in a second step, the adsorbent components
are subsequently filtered from the beer, which is then packaged for
storage, sale, and/or consumption.
[0017] Filtration processes that implement both an adsorption step
and a filtration step may be less efficient because of the
difficulties of filtering the adsorbent components. For example,
the adsorbent components may occupy void spaces of the porous
filter-aid material. That occupancy may reduce the permeability of
the filter-aid material, leading to an overall lower filtration
flow rate.
[0018] There have been previous attempts to improve upon the
traditional process of chill-proofing. Earlier attempts involved
creating a simple mixture of an adsorbent component and a
filtration component to combine the filtration and adsorption steps
into one, thus eliminating the need to filter the adsorbent
components. The term "simple mixture" is used herein to describe a
composition comprising at least one adsorbent component and at
least one filtration component where the two components are not
chemically bonded, thermally sintered, or precipitated together.
Simple mixtures may be somewhat ineffective as the components may
be subject to separation due to physical distress often experienced
in packaging and shipping. Therefore it would be desirable to
combine the adsorption and filtration processes into one step and
also ensure that the filtration components would not separate from
the adsorbent components.
[0019] U.S. Pat. No. 6,712,974 to Palm et al. describes a
filterable composite adsorbent comprising at least one adsorbent
component that is thermally sintered and/or chemically bonded to at
least one filtration component. The filterable composite adsorbent
of Palm retains the properties of both its adsorbent and filtration
components, and binds them in a fashion so as they do not
segregated upon physical distress, providing a means for adsorbing
particles and/or constituents while filtering the fluid in a single
step. Although Palm discloses a filterable composite adsorbent, it
does not disclose a filterable composite adsorbent where the
adsorbent components have a smaller average particle size, such as
1 micron or smaller. Such a small particle size may be achieved by
methods other than sintering or chemical bonding that are not
contemplated or suggested by Palm, for example, by in-situ
precipitation. Beneficially, a smaller adsorbent component particle
size may lead to an increased surface area and, consequently, an
increased efficiency at removing particles and/or constituents from
a fluid.
SUMMARY OF THE INVENTION
[0020] The present invention overcomes the disadvantages of the
prior art by providing an improved system and method for removing
particles and/or constituents suspended in a fluid. The filter-aid
materials comprising at least one filterable composite adsorbent
disclosed herein may be prepared in a manner that retains the
properties of both the filtration and adsorbent components. To that
end, a filter-aid material may be prepared that comprises at least
one filterable composite adsorbent that may be prepared by in-situ
precipitation of at least one adsorbent component on the surface of
at least one filtration component. In certain embodiments, such
in-situ precipitation may result in the adsorbent component being
intimately associated with the at least one filtration component
such that the components may be less susceptible to separation by
physical distress than a simple mixture of those components.
[0021] In certain embodiments, an in-situ precipitation process may
be used to create a filterable composite adsorbent having
relatively small particle-sized adsorbent components, for example,
less than 1 micrometer, on the surface of at least one filtration
component. Consequently, the filter-aid materials comprising at
least one filterable composite adsorbent disclosed herein may
provide a greater adsorptive surface area than prior
implementations, thereby enabling the filter-aid materials to
adsorb a greater amount of particles and/or constituents from a
fluid than was previously possible. The adsorptive effectiveness of
the filter-aid materials comprising at least one filterable
composite adsorbent disclosed herein may be evidenced by a lower
level of turbidity in the filtered fluid than could previously be
achieved.
[0022] The filterable composite adsorbent of the present invention
may be formed using an in-situ process that precipitates an
adsorbent component with a much smaller particle size and,
consequently, a much higher BET surface area than a thermally
sintered or chemically bonded composite. The larger BET surface
area may result in a filterable composite adsorbent with a greater
adsorptive capacity, allowing more particles and/or constituents to
be adsorbed by a filter-aid material comprising the filterable
composite adsorbent. As a result of the increased BET surface area,
the filter-aid materials comprising at least one filterable
composite adsorbent disclosed herein may be more effective at
removing particles and/or constituents from a fluid and may produce
a fluid with a relatively low turbidity value.
[0023] In certain embodiments, the filter-aid materials comprising
at least one filterable composite adsorbent disclosed herein may
reduce the turbidity of the filtered fluid as compared with
conventional techniques. In one embodiment, the turbidity of a
fluid filtered through the filter-aid materials comprising at least
one filterable composite adsorbent described herein is less than
the turbidity of a fluid filtered through a simple mixture having
the same proportion of adsorbent and filtration components as the
filter-aid material comprising at least one filterable composite
adsorbent. Further, the turbidity of a fluid filtered through the
filter-aid materials comprising at least one filterable composite
adsorbent may be less than the turbidity of a fluid filtered
through a thermally sintered or chemically bonded mixture, having
the same proportion of adsorbent and filtration components as the
filter-aid material comprising at least one filterable composite
adsorbent. In certain embodiments, the increased BET surface area
of the filter-aid material comprising at least one filterable
composite adsorbent as compared with known simple mixtures or
thermally sintered or chemically bonded composites may allow for a
greater adsorptive capacity, which may be due to the increased
surface area on which particles and/or constituents may be
adsorbed. While not wishing to be bound by theory, it is believed
that since more particles and/or constituents can be adsorbed by
the filter-aid material comprising at least one filterable
composite adsorbent disclosed herein, fewer particles may remain in
the filtered fluid, thereby reducing the turbidity of the filtered
fluid.
[0024] In accordance with certain embodiments, the adsorbent
component of the filter-aid material comprising at least one
filterable composite adsorbent has an average particle size less
than that of conventional filter-aid materials. In one embodiment,
the at least one adsorbent component has a particle size of less
than about 1 micrometer (micron). In another embodiment, the at
least one adsorbent component has a particle size ranging from
about 1 nanometer to about 100 nanometers. In a further embodiment,
the at least one adsorbent component has a particle size ranging
from about 1 nanometer to about 1 micron. Due its small average
particle size, the at least one adsorbent component of the
filter-aid materials comprising at least one filterable composite
adsorbent disclosed herein may have a larger BET surface area than
was previously possible. For instance, the at least one adsorbent
component may have a surface area ranging from about 50 to about
510 m.sup.2/g. Having a large adsorptive surface area may ensure
that there are a relatively large number of sites where the
particles and/or constituents to be removed can be adsorbed by the
filter-aid materials comprising at least one filterable composite
adsorbent.
[0025] Although many known adsorbents, in their un-reacted, powder
form, may have relatively large surface areas (e.g. ranging from
about 300 to about 1200 m.sup.2/g), such un-reacted powder
adsorbents may tend to aggregate when they are bonded to a
filtration component using conventional techniques, thus acting to
lower the effective surface area. In contrast, the filter-aid
material comprising at least one filterable composite adsorbent
disclosed herein may be prepared using an in-situ process that
prevents aggregation and enables the at least one adsorbent
component to form with smaller average particle sizes than could
previously be achieved. Consequently, the filterable composite
adsorbent may support larger adsorptive surface areas which, in
turn, provide for more effective adsorption properties.
[0026] The filter-aid materials comprising at least one filterable
composite adsorbent disclosed herein may be produced with a wide
range of permeabilities. In one embodiment, the filter-aid
materials comprising at least one filterable composite adsorbent
disclosed herein have a permeability ranging from about 0.001 to
about 1000 Darcies ("Da"). In another embodiment, the permeability
ranges from about 0.05 to about 10.00 Da. The range of permeability
may allow for either a high flow rate or a lower flow rate. For
instance, a lower flow rate may be about 1 ml/min cm.sup.2, while a
high flow rate may be at least about 90 ml/min cm.sup.2. In one
embodiment, the flow rate is about 1.2 ml/min cm.sup.2. In another
embodiment, the flow rate is about 4 ml/min cm.sup.2. In a further
embodiment, the flow rate ranges from about 1.2 to about 4 ml/min
cm.sup.2. Flow rate has a generally measurable pressure which
varies with the flow rate. In one embodiment, the pressure is about
1.2 psi. In another embodiment, the pressure is about 15 psi. In a
further embodiment, the pressure ranges from about 1.2 to about 15
psi. In yet another embodiment, the flow rate is from about 1.2 to
about 4 ml/min cm.sup.2 and the pressure is from about 1.2 to about
15 psi.
[0027] The filter-aid materials comprising at least one filterable
composite adsorbent disclosed herein also may exhibit various wet
densities. For example, the filter-aid material comprising at least
one filterable composite adsorbent may have a wet density ranging
from about 10 to about 25 lb/ft.sup.3. As wet density reflects the
void volume of the adsorbent component to entertain matter in the
filtration process, a lower wet density may indicate that the
adsorbent component has a high void volume and thus can adsorb more
particles and/or constituents in the fluid.
[0028] In certain embodiments, the at least one adsorbent component
of the filterable composite adsorbent may be a silica gel and the
at least one filtration component may be chosen from natural
glasses, such as expanded perlite, and biogenic silicas, such as
diatomite. In one embodiment, the at least one adsorbent component
is a silica gel and the at least one filtration component is
diatomite. In another embodiment, the at least one adsorbent
component is a silica gel and the at least one filtration component
is perlite. Of course, those skilled in the art will understand
that other adsorbent and filtration components may be employed. For
example, in a further embodiment, the at least one filtration
component may be chosen from biogenic silicas (such as rice hull
ash and sponge spicules); natural glasses (such as pumice, expanded
pumice, pumicite, expanded obsidian, and expanded volcanic ash);
buoyant glasses; buoyant polymers; and celluloses.
[0029] In some embodiments, the filter-aid material comprises at
least one additional filtration component mixed with the at least
one filterable composite adsorbent. The at least one filtration
component of the filterable composite adsorbent and the at least
one additional filtration component of the filter-aid material may
be the same or different. In one embodiment, the at least one
additional filtration component may be chosen from biogenic silicas
(including, but not limited to, rice hull ash and sponge spicules);
natural glasses (including, but not limited to, pumice, expanded
pumice, pumicite, expanded obsidian, and expanded volcanic ash);
buoyant glasses; buoyant polymers; and celluloses. In another
embodiment, the at least one additional filtration component is
diatomite. In a further embodiment, the at least one additional
filtration component is perlite.
[0030] The filter-aid materials comprising at least one filterable
composite adsorbent disclosed herein may be made in various forms.
For example, in one embodiment, the filter-aid materials comprising
at least one filterable composite adsorbent are in the form of a
powder. In another embodiment, the filter-aid materials may be in a
form chosen from sheets, pads, and cartridges. In a further
embodiment, the filter-aid materials are formed in-situ in the form
chosen from rigid shapes, including but not limited to disks,
cylinders, plates and polyhedrons. In yet another embodiment, the
filter-aid materials may be in a form chosen from monolithic
supports and aggregate supports. In yet a further embodiment, the
filter-aid materials are a form chosen from monolithic substrates
and aggregate substrates. In still yet another embodiment, the
filter-aid materials are pulverized.
[0031] Various methods for making the filter-aid materials
comprising at least one filterable composite adsorbent disclosed
herein are contemplated. For instance, in one embodiment, sodium
silicate may be mixed in an aqueous solution with an acid, such as
sulfuric acid, until the solution pH is sufficiently low enough to
support silica gel precipitation in the presence of at least one
porous filtration component. At least one filtration component is
then added to the solution and stirred until the silica precipitate
begins to gel. The addition of the acid causes the at least one
adsorbent component, silica gel in this illustrative embodiment, to
precipitate onto the surface of the at least one filtration
component, thus forming the filterable composite adsorbent.
[0032] In another embodiment, the filterable composite adsorbent
may further be mixed with at least one additional filtration
component to form a final filter-aid material product. In one
embodiment, the at least one filtration component of the filterable
composite adsorbent and the at least one additional filtration
component of the filter-aid material are the same. In another
embodiment, the at least one filtration component of the filterable
composite adsorbent and the at least one additional filtration
component of the filter-aid material are different. Those skilled
in the art will appreciate that other methods alternatively may be
used to synthesize the filterable composite adsorbent in accordance
with the present disclosure.
[0033] One embodiment disclosed herein is a process for removing
particles and/or constituents from a fluid comprising (i) providing
at least one filter-aid material comprising at least one filterable
composite adsorbent, (ii) pre-coating at least one filter element
with the at least one filter-aid material comprising at least one
filterable composite adsorbent, (iii) suspending the at least one
coated filter element in a fluid containing the particles and/or
constituents to be adsorbed.
[0034] Another embodiment is a method of adsorbing and filtering
particles and/or constituents from a fluid that comprises passing a
fluid containing particles and/or constituents to be adsorbed
through a filter-aid materials comprising at least one filterable
composite adsorbent, as disclosed herein, that is supported on a
septum.
[0035] In an alternative embodiment, the method of adsorbing and
filtering comprises passing a fluid containing particles and/or
constituents to be adsorbed through a filter-aid materials
comprising at least one filterable composite adsorbent, in the form
of a rigid shape, as described above, supported on a septum.
DETAILED DESCRIPTION OF THE INVENTION
[0036] A. Filterable Composite Adsorbent
[0037] The filter-aid materials disclosed herein comprise at least
one filterable composite adsorbent comprising at least one
adsorbent component, and at least one filtration component having
pores through which a fluid can pass, wherein the at least one
adsorbent component has been precipitated in-situ on the surface of
the at least one filtration component. A filter element may be used
to support the filter-aid material comprising at least one
filterable composite adsorbent. In one embodiment, filter element
contains filter element voids through which fluid may flow. The
filter-aid materials comprising at least one filterable composite
adsorbent may retain both the adsorptive properties of the at least
one adsorbent component and the porous structure of the at least
one filtration component, thus enhancing the utility of the
filter-aid materials comprising at least one filterable composite
adsorbent.
[0038] Unlike simple mixtures in which adsorbent and filtration
components may be mixed or blended together, the at least one
adsorbent component is precipitated in-situ onto the surface of the
at least one filtration component. As a result, while simple
mixtures may segregate upon suspension (e.g., in fluid, conveyance,
or transport), the filter-aid material comprising at least one
filterable composite adsorbent of the present invention may retain
both its component adsorptive and filtration properties. The
in-situ precipitation of the at least one adsorbent component on
the at least one filtration component may also have superior
absorptive and filtration properties than a thermally sintered or
chemically bonded composite, because the in-situ precipitation
process may produce a filter-aid material comprising at least one
filterable composite adsorbent with smaller particle-sized
adsorbent components and, consequently, a larger surface area for
adsorption. The larger surface area may allow the filter-aid
material comprising at least one filterable composite adsorbent to
adsorb a greater number of particles and/or constituents which, in
turn, may result in a lower turbidity level for the filtered
fluid.
[0039] The average particle size of the at least one adsorbent
component that forms upon the surface of the at least one
filtration component may be less than about 1 micrometer. In one
embodiment, the average particle size is less than about 0.5
microns. In another embodiment, the average particle size is less
than about 0.2 microns. In a further embodiment, the average
particle size is less than about 0.1 microns. In yet another
embodiment, the average particle size is less than about 50
nanometers. In yet a further embodiment, the average particle size
is less than about 30 nanometers. In still another embodiment, the
average particle size is less than about 20 nanometers. In still a
further embodiment, the average particle size is less than about 10
nanometers. In another embodiment, the average particle size ranges
from about 5 to about 50 nanometers. In a further embodiment, the
average particle size ranges from about 2 to about 100 nanometers.
In yet another embodiment, the average particle size ranges from
about 5 nanometers to about 1 micrometer.
[0040] In certain embodiments, the BET surface area of the at least
one adsorbent component may increase as the mean diameter of the at
least one adsorbent component decreases. In one embodiment, the BET
surface area of the at least one adsorbent component formed upon
the surface of the at least one filtration component is greater
than about 2 m.sup.2/g. In another embodiment, the BET surface area
is greater than about 5 m.sup.2/g. In a further embodiment, the BET
surface area is greater than about 10 m.sup.2/g. In yet another
embodiment, the BET surface area is greater than about 25
m.sup.2/g. In yet a further embodiment, the BET surface area is
greater than about 50 m.sup.2/g. In still another embodiment, the
BET surface area is greater than about 85 m.sup.2/g. In still a
further embodiment, the BET surface area is greater than about 125
m.sup.2/g. In another embodiment, the BET surface area is greater
than about 250 m.sup.2/g. In a further embodiment, the BET surface
area ranges from about 2 m.sup.2/g to about 2550 m.sup.2/g. In yet
another embodiment, the BET surface area ranges from about 50
m.sup.2/g to about 510 m.sup.2/g.
[0041] The larger BET surface area of the at least one adsorbent
component may allow the filter-aid materials comprising at least
one filterable composite adsorbent to reduce the number of
particles and/or constituents that contribute to turbidity of the
fluid. The filter-aid materials comprising at least one filterable
composite adsorbent may entrap particles and/or constituents from
the unfiltered fluid, resulting in the filtered fluid having fewer
particles and/or constituents. Further, the turbidity of a fluid
filtered through the filter-aid materials comprising at least one
filterable composite adsorbent disclosed herein may be less than
the turbidity of a fluid filtered through a simple mixture of at
least one adsorbent component and at least filtration component,
where the proportion of adsorbent component to filtration component
in the simple mixture is similar to, or even greater than, the
proportion of adsorbent component to filtration component of the
filter-aid materials comprising at least one filterable composite
adsorbent disclosed herein. Further, the turbidity of a fluid
filtered through the filter-aid materials comprising at least one
filterable composite adsorbent disclosed herein may be less than
the turbidity of a fluid filtered through a thermally sintered or
chemically bonded composite of an adsorbent component and a
filtration component, where the proportion of adsorbent component
to filtration component in the thermally sintered or chemically
bonded composite is similar to, or even greater than, the
proportion of adsorbent component to filtration component of the
filter-aid materials comprising at least one filterable composite
adsorbent disclosed herein.
[0042] The filter-aid materials comprising at least one filterable
composite adsorbent disclosed herein may be processed to provide a
wide range of flow rates, which are directly related to
permeability. Permeability may be reported in units of darcies
("Da"). One darcy corresponds to the permeability through a filter
medium 1 cm thick which allows 1 cm.sup.2 of fluid with a viscosity
of 1 centipoise to pass through an area of 1 cm.sup.2 in 1 second
under a pressure differential of 1 atm (i.e., 101.325 kPa).
Permeability may be determined using a device designed to form a
filter cake on a septum from a suspension of filter-aid material in
water and then measuring the time required for a specified volume
of water to flow through a measured thickness of filter cake of
known cross-sectional area. Many filtration media suitable for
micro filtration, such as diatomite and perlite products, are
commercially available and span a wide range of permeability,
ranging from about 0.001 Da to over 30 Da, such as from about 0.05
Da to over 10 Da. Filter-aid material for coarse filtration, such
as sand, may have greater permeabilities, such as at least about
1000 Da.
[0043] The selection of filtration permeability for a specific
filtration process depends in part on the flow rate and degree of
fluid clarification required for the particular application. In
many cases, the flow of fluid through a filter-aid material may be
closely related to the nature of the filtration component's
porosity. Within a given family of filtration components, those of
low permeability may have smaller pores capable of providing
greater clarity because smaller particles can be retained during
the filtration process, whereas those of high permeability may have
larger pores capable of providing greater fluid flow, but usually
at the expense of the ability to remove particles as small as those
removed by their low permeability counterparts.
[0044] The adsorbent component may be selected from any suitable
adsorbent known to the skilled artisan or hereafter discovered. In
certain embodiments, the adsorbent may be a form of silica. In one
embodiment, the at least one adsorbent component may be chosen from
silica gels. Silica gels are a form of silicon dioxide (SiO.sub.2),
which may occur in nature as sand. In general, however, sand is
crystalline and non-porous while silica gels are non-crystalline
and porous. In another embodiment, the at least one adsorbent
component may be a colloidal silica. In a further embodiment, the
at least one adsorbent component may be a fumed silica. In yet
another embodiment, the at least one adsorbent component may be a
silica fume. In yet a further embodiment, the at least one
adsorbent component is chosen from silicates. Non-limiting examples
of suitable silicates include alumina silicate, calcium silicate,
and magnesium silicate. In still another embodiment, the at least
one adsorbent component is chosen from an alumina. In one
embodiment, the alumina adsorbent component is an alumina silicate.
In another embodiment, the alumina adsorbent component is a porous
alumina.
[0045] The silica adsorbent may, in some embodiments, further be
chosen from amorphous or crystalline silicas. In one embodiment,
the silica adsorbent is an amorphous silica. In another embodiment,
the silica is a crystalline silica.
[0046] Filtration components suitable for use in preparation of the
filter-aid materials comprising at least one filterable composite
adsorbent disclosed herein may possess a variety of pore sizes. In
one embodiment, the filtration component pore size is a relatively
large pore size, for example, a mean pore diameter of about 10
microns, such that it is particularly well suited for particle
entrapment, thereby permitting mechanical filtration and/or
clarification by means of removal of particles and/or constituents.
In another embodiment, the filtration component pore size is a
relatively small pore size, for example, a mean pore diameter of
about 2 microns.
[0047] Filtration components suitable for use in the preparation of
the filterable composite adsorbent disclosed herein may possess a
variety of surface areas. In one embodiment, the filtration
component may have a relatively large surface area. In another
embodiment, the filtration component may have a relatively small
surface area. Without wishing to be bound by theory, it is believed
that a filtration component with a large surface area may allow for
a reduction in the thickness of an adsorbent component coating
which may be formed thereon, for example, a precipitated silica
gel. The reduced thickness of the adsorbent coating is believed to
provide for more sites for adsorption of the particles and/or
constituents to be removed. In one embodiment, the surface area of
the filtration component is at least about 1 m.sup.2/g. In another
embodiment, the surface area is at least about 3 m.sup.2/g. In a
further embodiment, the surface area is at least about 15
m.sup.2/g. In yet another embodiment, the surface area is at least
about 30 m.sup.2/g. In yet a further embodiment, the surface area
is at least about 50 m.sup.2/g. In still another embodiment, the
surface area ranges from about 1 m.sup.2/g to about 100 m.sup.2/g.
In still yet another embodiment, the surface area is less than
about 500 m.sup.2/g.
[0048] In one embodiment, the at least one filtration component
and/or the at least one additional filtration component is
diatomite (a biogenic silica). In another embodiment, the at least
one filtration component and/or the at least one additional
filtration component is perlite (a natural glass). In another
embodiment, the filtration components are chosen from biogenic
silica, including but not limited to diatomite, rice hull ash, and
sponge spicules. In a further embodiment, the filtration components
are chosen from buoyant glasses. One example of buoyant glasses are
natural glasses, including but not limited to pumice, expanded
pumice, pumicite, expanded obsidian, expanded volcanic ash, and
sand. In yet another embodiment, the filtration components are
chosen from synthetic glasses. Examples of synthetic glasses
include but are not limited to fiber glass, controlled pore glass,
and foamed glass. In yet a further embodiment, the filtration
components are chosen from buoyant polymers. Buoyant polymers
include but are not limited to fibrous polymers (such as fibrous
nylon and fibrous polyester) and powdered polymers (such as
polyvinylchloride-acrylic copolymer powder). In still another
embodiment, the filtration components are chosen from cellulose. In
still a further embodiment, the filtration components are chosen
from silicates. Non-limiting examples of suitable silicates include
alumina silicate, calcium silicate, and magnesium silicate. In
still yet another embodiment, the filtration components are chosen
from an alumina. In one embodiment, the alumina filtration
component is an alumina silicate. In another embodiment, the
alumina filtration component is a porous alumina.
[0049] In one embodiment, the at least one filtration component
and/or the at least one additional filtration component may
comprise a mixture of two or more of the filtration components
mentioned above. For example, in one embodiment, the at least one
filtration component and/or the at least one additional filtration
component may comprise a mixture of diatomite and perlite. The at
least one filtration component and the at least one additional
filtration component (if used) may be the same or different. In one
embodiment, the filtration components are the same. In another
embodiment, the filtration components are different.
[0050] The term "biogenic silica" as used herein refers to silica
produced or brought about by living organisms. One example of
biogenic silica is diatomite, obtained from diatomaceous earth
(also known as kieselguhr), which is a sediment enriched in
biogenic silica in the form of the siliceous frustules (i.e.,
shells or skeletons) of diatoms. Diatoms are a diverse array of
microscopic, single-celled algae of the class Bacillariophyceae,
which possess an ornate siliceous skeleton (frustule) of varied and
intricate structure comprising two valves which, in the living
diatom, fit together much like a pill box. The morphology of the
frustules may vary widely among species and serves as the basis for
taxonomic classification; over at least 2,000 distinct species are
known. The surface of each valve is punctuated by a series of
openings that comprise the complex fine structure of the frustule
and impart a design that is distinctive to individual species. The
size of typical frustules may range from about 0.75 .mu.m to about
1,000 .mu.m. In one embodiment, the size ranges from about 10 .mu.m
to about 150 .mu.m. Those frustules are sufficiently durable to
retain much of their porous and intricate structure virtually
intact through long periods of geologic time when preserved in
conditions that maintain chemical equilibrium. Other sources of
biogenic silica are known, as many plants, animals, and
microorganisms provide concentrated sources of silica with unique
characteristics. For example, rice hulls contain sufficient silica
that they are commercially ashed for their siliceous residue, a
product known familiarly as "rice hull ash." Certain sponges are
also concentrated sources of silica, the remnants usually occurring
in geologic deposits as acicular spicules.
[0051] The term "natural glass" as used herein refers to natural
glasses, commonly referred to as volcanic glasses, that are formed
by the rapid cooling of siliceous magma or lava. Several types of
natural glasses are known, including, for example, perlite, pumice,
pumicite, obsidian, and pitchstone. Prior to processing, perlite
may be gray to green in color with abundant spherical cracks that
cause it to break into small pearl-like masses. Pumice is a
lightweight glassy vesicular rock. Obsidian may be dark in color
with a vitreous luster and a characteristic conchoidal fracture.
Pitchstone has a waxy resinous luster and may be brown, green, or
gray. Volcanic glasses such as perlite and pumice occur in massive
deposits and find wide commercial use. Volcanic ash, often referred
to as tuft when in consolidated form, comprises small particles or
fragments that may be in glassy form. As used herein, the term
natural glass encompasses volcanic ash.
[0052] Natural glasses may be chemically equivalent to rhyolite.
Natural glasses that are chemically equivalent to trachyte, dacite,
andesite, latite, and basalt are known but may be less common. The
term obsidian is generally applied to large numbers of natural
glasses that are rich in silica. Obsidian glasses may be classified
into subcategories according to their silica content, with
rhyolitic obsidians (containing typically about 73% SiO.sub.2 by
weight) as the most common.
[0053] Perlite is a hydrated natural glass that may contain, for
example, about 72 to about 75% SiO.sub.2, about 12 to about 14%
Al.sub.2O.sub.3, about 0.5 to about 2% Fe.sub.2O.sub.3, about 3 to
about 5% Na.sub.2O, about 4 to about 5% K.sub.2O, about 0.4 to
about 1.5% CaO (by weight), and small amounts of other metallic
elements. Perlite may be distinguished from other natural glasses
by a higher content (such as about 2 to about 5% by weight) of
chemically bonded water, the presence of a vitreous, pearly luster,
and characteristic concentric or arcuate onion skin like (i.e.,
perlitic) fractures.
[0054] Perlite products may be prepared by milling and thermal
expansion, and may possess unique physical properties such as high
porosity, low bulk density, and chemical inertness.
[0055] Pumice is a natural glass characterized by a mesoporous
structure (e.g., having pores or vesicles with a size up to about 1
mm). The porous nature of pumice gives it a very low apparent
density, in many cases allowing it to float on the surface of
water. Most commercial pumice contains from about 60% to about 70%
SiO.sub.2 by weight. Pumice may be processed by milling and
classification, and products may be used as lightweight aggregates
and also as abrasives, adsorbents, and fillers. Unexpanded pumice
and thermally expanded pumice may also be used as filtration
components in some cases as can volcanic ash.
[0056] The appropriate selection of the at least one adsorbent
component and the at least one filtration component of the
filter-aid materials comprising at least one filterable composite
adsorbent, as well as any at least one additional filtration
component, disclosed herein may be determined by the specific
application intended. For example, in a filtration process that
demands high clarity but tolerates slower flow rate, a filter-aid
material comprising at least one filterable composite adsorbent of
low permeability may be used, whereas in a filtration process that
demands high flow rate but does not require high clarity, a
filter-aid materials comprising at least one filterable composite
adsorbent of high permeability may be used. Similar reasoning
applies to the choice of the at least one adsorbent component, and
to the at least one filterable composite adsorbent when used in
conjunction with other materials, or when preparing mixtures
containing the products.
[0057] In one embodiment disclosed herein, a silica gel adsorbent
for chill-proofing of beer is precipitated in-situ upon expanded
perlite. The resulting composite has both the properties of the
chill-proofing obtained from the silica gel adsorbent, as well as
the filtration properties of the expanded perlite filtration
component. In another embodiment, the resulting silica gel/expanded
perlite filterable composite adsorbent may further be mixed with at
least one additional filtration component. In one embodiment, the
at least one additional filtration component may also comprise
expanded perlite. In another embodiment, the at least one
additional filtration component may comprise a filtration component
that is different than expanded perlite.
[0058] In another embodiment, silica gel may be precipitated
in-situ onto diatomite, a biogenic silica. The resulting composite
has both the properties of the chill-proofing obtained from the
silica gel adsorbent, as well as the filtration properties of the
diatomite filtration component. In another embodiment, the
resulting silica gel/diatomite filterable composite adsorbent may
further be mixed with an at least one additional filtration
component. In one embodiment, the at least one additional
filtration component may also comprise diatomite. In another
embodiment, the at least one additional filtration component may
comprise a filtration component that is different than
diatomite.
[0059] In one embodiment, the filter-aid material comprising at
least one filterable composite adsorbent may be pulverized. In
another embodiment, the filter-aid material may comprise at least
one filterable composite adsorbent that has been pulverized.
Pulverization may lead to an increase in surface area of the
filter-aid material and/or filterable composite adsorbent and,
thus, an increased ability to adsorb particles and/or constituents
in the fluid to be filtered. In addition, pulverization may lead to
a greater number of unlocked silica gel sites of the filter-aid
material and/or filterable composite adsorbent and, thus, an
increased ability to adsorb particles and/or constituents in the
fluid to be filtered. However, too much pulverization can result in
a decrease in permeability. Thus, in one embodiment, the
pulverization is controlled to achieve the desired balance between
adsorbency and permeability.
[0060] B. Methods for Preparing a Filterable Composite
Adsorbent
[0061] Sodium silicate is used herein to refer to any one of
several compounds comprising sodium oxide (Na.sub.2O) and silica
(SiO.sub.2). Such combinations may include, for example, sodium
ortho silicate (Na.sub.4SiO.sub.4), sodium meta silicate
(Na.sub.2SiO.sub.3), and sodium disilicate
(Na.sub.2Si.sub.2O.sub.5). In one embodiment, the sodium silicate
is a diatomite-based based sodium silicate. In another embodiment,
sodium silicate is substituted in whole or in part for at least one
ammonium silicate and/or at least one alkali metal silicate, such
as lithium, sodium, potassium, rubidium, and cesium silicates. In
certain embodiments, sodium silicate having an SiO.sub.2/Na.sub.2O
ratio of about 3.2 and a concentration of about 20% is added to
water to a concentration of about 2% by weight. Sodium silicate
with a SiO.sub.2/Na.sub.2O ratio of 3.2 and a concentration of 20%
may be purchased, for example, from World Minerals Inc.
[0062] An acid or salt thereof may be added to the slurry in an
amount sufficient to increase the acidity (i.e., reduce the pH) of
the slurry to a pH range suitable for the precipitation of silica
gel. Any suitable acid may be selected, such selection being within
the skill of one in the art. In one embodiment, the acid may be
sulfuric acid. In another embodiment, the acid may be phosphoric
acid. In still another embodiment, the acid may by hydrochloric
acid. In yet another embodiment, the acid may be nitric acid. In
still yet another embodiment, the acid may be acetic acid. A
filtration component, chosen from among any suitable filtration
component previously known or hereinafter discovered, may then be
added to the solution. In one embodiment, the filtration component
is the commercially-available filtration component Celite Standard
Super-Cel.RTM., manufactured by World Minerals Inc. In another
embodiment, the filtration component is the commercially-available
filtration component Celite Hyflo Super-Cel.RTM., manufactured by
World Minerals Inc. In a further embodiment, the filtration
component is the commercially-available filtration component Celite
512.RTM., manufactured by World Minerals Inc. In a further
embodiment, the filtration component is the commercially-available
filtration component Celite 512Z.RTM., manufactured by World
Minerals Inc. In still another embodiment, the filtration component
is the commercially-available filtration component Celite 289.RTM.,
manufactured by World Minerals Inc. In still a further embodiment,
the filtration component is the commercially-available filtration
component Filter-Cel.RTM., manufactured by World Minerals Inc.
[0063] After the filtration component has been added, the slurry is
stirred periodically until gelling occurs. This may take about 25
to about 60 minutes depending upon the acidity of the solution and
the sodium silicate concentration of the slurry. Next, water is
added, for example from about 20 mL to about 500 mL of water, to
disperse the gelled slurry. The slurry is then filtered and the
resulting cake is washed with water. Then the cake is dried until
the excess fluid in the cake has evaporated. For example, the cake
may be dried at a temperature ranging from about 110.degree. C. to
about 200.degree. C.
[0064] The amount of the filtration component added may be based
upon the amount of silica gel desired to be in the resultant
filterable composite adsorbent and/or final filter-aid material.
While increasing the percentage of silica gel generally acts to
increase the filter-aid material's ability to act as an adsorbent,
it generally acts to decrease its ability to act as a filter
material. Conversely, decreasing the percentage of silica gel
generally acts to decrease the filter-aid material's ability to act
as an adsorbent while increasing its ability to act as a filter
material.
[0065] Accordingly, the amount of the adsorbent component in the
filterable composite adsorbent may comprise from between greater
than about 0 to about 100% by weight of the total filterable
composite adsorbent. In one embodiment, the adsorbent component may
comprise greater than about 5% by weight of the total filterable
composite adsorbent. In another embodiment, the adsorbent component
may comprise greater than about 15% by weight of the total
filterable composite adsorbent. In another embodiment, the
adsorbent component may comprise greater than about 25% by weight
of the total filterable composite adsorbent. In another embodiment,
the adsorbent component may comprise greater than about 40% by
weight of the total filterable composite adsorbent. In another
embodiment, the adsorbent component may comprise greater than about
50% by weight of the total filterable composite adsorbent. In
another embodiment, the adsorbent component may comprise greater
than about 70% by weight of the total filterable composite
adsorbent. In another embodiment, the adsorbent component may
comprise greater than about 80% by weight of the total filterable
composite adsorbent.
[0066] The amount of the filtration component in the filterable
composite adsorbent may comprise from between greater than about 0
to about 100% by weight of the total filterable composite
adsorbent. In one embodiment, the filtration component may comprise
greater than about 5% by weight of the total filterable composite
adsorbent. In another embodiment, the filtration component may
comprise greater than about 15% by weight of the total filterable
composite adsorbent. In another embodiment, the filtration
component may comprise greater than about 25% by weight of the
total filterable composite adsorbent. In another embodiment, the
filtration component may comprise greater than about 40% by weight
of the total filterable composite adsorbent. In another embodiment,
the filtration component may comprise greater than about 50% by
weight of the total filterable composite adsorbent. In another
embodiment, the filtration component may comprise greater than
about 70% by weight of the total filterable composite adsorbent. In
another embodiment, the filtration component may comprise greater
than about 80% by weight of the total filterable composite
adsorbent.
[0067] In one embodiment, the adsorbent component may comprise from
about 5% to about 15% by weight of the total filterable composite
adsorbent and the filtration component may comprise from about 85%
to about 95% by weight of the total filterable composite adsorbent.
In another embodiment, the adsorbent component may comprise from
about 65% to 75% by weight of the total filterable composite
adsorbent and the filtration component may comprise from 25% to 35%
by weight of the total filterable composite adsorbent. In a further
embodiment, the filterable composite adsorbent comprises a greater
amount by weight of the adsorbent component than the filtration
component.
[0068] After formation of the filterable composite adsorbent, the
filterable composite adsorbent may then be mixed with at least one
additional filtration component. The at least one additional
filtration component may be chosen from any suitable filtration
component previously known or hereinafter discovered and may be
either the same or different from the at least one filtration
component in the filterable composite adsorbent. In one embodiment,
the additional filtration component is the commercially-available
filtration component Celite Standard Super-Cel.RTM., manufactured
by World Minerals Inc. In another embodiment, the additional
filtration component is the commercially-available filtration
component Celite Hyflo Super-Cel.RTM., manufactured by World
Minerals Inc. In a further embodiment, the additional filtration
component is the commercially-available filtration component Celite
512.RTM., manufactured by World Minerals Inc. In a further
embodiment, the filtration component is the commercially-available
filtration component Celite 512Z.RTM., manufactured by World
Minerals Inc. In yet another embodiment, the additional filtration
component is the commercially-available filtration component Celite
289.RTM., manufactured by World Minerals Inc. In yet a further
embodiment, the additional filtration component is the
commercially-available filtration component Filter-Cel.RTM.,
manufactured by World Minerals Inc.
[0069] In cases in which the filter-aid material comprising at
least one filterable composite adsorbent further comprises at least
one additional filtration component, the additional filtration
component may comprise from greater than about 0% to about 100% of
the total weight of the filter-aid material. In one embodiment, the
additional filtration component may comprise greater than about 5%
by weight of the total filter-aid material. In another embodiment,
the additional filtration component may comprise greater than about
30% by weight of the total filter-aid material. In a further
embodiment, the additional filtration component may comprise
greater than about 50% by weight of the total filter-aid material.
In yet another embodiment, the additional filtration component may
comprise greater than about 65% by weight of the total filter-aid
material. In yet a further embodiment, the additional filtration
component may comprise greater than about 80% by weight of the
total filter-aid material.
[0070] In cases in which the filter-aid material comprising at
least one filterable composite adsorbent further comprises at least
one additional filtration component, the filterable composite
adsorbent may comprise from greater than about 0% to about 100% of
the total weight of the filter-aid material. In one embodiment, the
filterable composite adsorbent may comprise greater than about 5%
by weight of the total filter-aid material. In another embodiment,
the filterable composite adsorbent may comprise greater than about
30% by weight of the total filter-aid material. In a further
embodiment, the filterable composite adsorbent may comprise greater
than about 50% by weight of the total filter-aid material. In yet
another embodiment, the filterable composite adsorbent may comprise
greater than about 65% by weight of the total filter-aid material.
In yet a further embodiment, the filterable composite adsorbent may
comprise greater than about 80% by weight of the total filter-aid
material.
[0071] In one embodiment, the at least one additional filtration
component may comprise from about 60% to about 70% by weight of the
total filler-aid material and the filterable composite adsorbent
may comprise from about 30% to about 40% by weight of the total
filler-aid material.
[0072] Specific properties of filter-aid materials comprising at
least one filterable composite adsorbent can be modified by further
physical or chemical reaction of the material after the initial
filter-aid material comprising at least one filterable composite
adsorbent has been made, for example to enhance at least one
property (for example, solubility and surface characteristics)
and/or to yield a new product with a specialized use. Examples of
such further modifications include, for example, hydration, acid
washing, surface treatment, and organic derivatization, as
disclosed, for example, in U.S. Pat. No. 6,712,974 to Palm et
al.
[0073] C. Methods of Using a Filterable Composite Adsorbent
[0074] The filter-aid material comprising at least one filterable
composite adsorbent described herein may be used in many of the
same applications as currently available adsorbents, but offers
added properties, such as, for example, increased permeability, low
centrifuged wet density, and uniquely shaped particles (e.g.,
fibers), as well as improved efficiency and/or economy.
[0075] The filter-aid material comprising at least one filterable
composite adsorbent disclosed herein, and its optional further
modifications, may be used in filtration applications in a manner
analogous to that of porous filtration media. Filter-aid materials
comprising at least one filterable composite adsorbent may be
applied to a septum to improve clarity and increase flow rate in
filtration processes or added directly to the fluid. Depending on
the particular separation involved, filter-aid materials comprising
at least one filterable composite adsorbent may be used in
pre-coating, body feeding, or both.
[0076] In one embodiment, the method of adsorption and filtration
comprises (i) providing a filter-aid material comprising at least
one filterable composite adsorbent, (ii) pre-coating a filter
element with the filterable composite adsorbent, and (iii)
suspending the filter-aid material comprising at least one
filterable composite adsorbent in a fluid containing particles
and/or constituents to be removed from the fluid, wherein the
filterable composite adsorbent may be supported on a filter
element.
[0077] In another embodiment, the method of adsorption and
filtration comprises (i) providing a filterable composite
adsorbent, (ii) further mixing the filterable composite adsorbent
with an at least second filtration component to form a filler-aid
material (iii) pre-coating a filter element with the filler-aid
material, and (iv) suspending the filter-aid material in a fluid
containing particles and/or constituents to be removed from the
fluid, wherein the filter-aid material may be supported on a filter
element.
[0078] To maximize the adsorption of particles and/or constituents,
such as proteins, contributing to chill haze, one embodiment
disclosed herein comprises a combination of pre-coating and body
feeding.
[0079] In an another embodiment, the method of adsorption and
filtration comprises the step of passing a fluid containing
undesired particles or constituents to be adsorbed through a
filter-aid material comprising at least one filterable composite
adsorbent, in the form of a rigid shape supported on a septum.
[0080] The filter-aid material comprising at least one filterable
composite adsorbent disclosed herein can be shaped, molded,
extruded, sintered, or otherwise formed into permeable sheets,
plates, disks, polyhedrons, or other formed shapes that have
adsorbent properties. Fluids can then be passed through the
filter-aid material comprising at least one filterable composite
adsorbent to achieve both filtration and adsorption.
[0081] The filter-aid material comprising at least one filterable
composite adsorbent disclosed herein may be used in conjunction
with other media (e.g., different porous filtration component
materials) to form a filter-aid material for use in filtration
applications and/or to further modify or optimize a filtration
process. For example, mixtures of the filterable composite
adsorbent with, for example, diatomite, expanded perlite, pumicite,
natural glass, cellulose, activated charcoal, clay, or other
materials, may be useful additional filtration components.
Sometimes, these blends are more elaborate and enable the blend to
be formed into sheets, pads, cartridges, or monolithic or aggregate
media capable of being used as supports or substrates.
[0082] The filter-aid materials comprising at least one filterable
composite adsorbent disclosed herein can also be useful in
applications other than filtration, since adsorbents or filtration
media can be useful in applications that do not necessarily depend
explicitly on either conventional adsorption or filtration. For
example, substances such as silica gel, fumed silica, neutral clay,
alkaline clay, zeolites, catalysts, polymers, and alkaline earth
silicate hydrates can be used as fillers, and biogenic silica,
natural glass, expanded perlite, pumice, expanded pumice, pumicite,
expanded obsidian, expanded volcanic ash, buoyant glass, buoyant
polymer, and cellulose can also be used as fillers.
[0083] Many other modifications and variations of the invention as
hereinbefore set forth can be made without departing from the
spirit and scope thereof. Other than in the examples, or where
otherwise indicated, all numbers expressing quantities of
ingredients, reaction conditions, and so forth used in the
specification and claims are understood as being modified in all
instances by the term "about." Accordingly, unless indicated to the
contrary, the numerical parameters set forth in the following
specification and attached claims are approximations that may vary
depending upon the desired properties sought to be obtained herein.
At the very least, and not as an attempt to limit the application
of the doctrine of equivalents to the scope of the claims, each
numerical parameter should be construed in light of the number of
significant digits and ordinary rounding approaches.
[0084] Notwithstanding that the numerical ranges and parameters
setting forth the broad scope are approximations, the numerical
values set forth in the specific examples are reported as precisely
as possible. Any numerical value, however, inherently contain
certain errors necessarily resulting from the standard deviation
found in their respective testing measurements.
[0085] The headers used in this specification are presented for the
convenience of the reader and not intended to be limiting of the
inventions described herein. By way of non-limiting illustration,
concrete examples of certain embodiments of the present disclosure
are given below.
EXAMPLES
[0086] Several filter-aid materials comprising at least one
filterable composite adsorbent as disclosed herein, as well as
methods for preparing them, are described in the following
examples, which are offered by way of illustration and not by way
of limitation.
Example 1
[0087] The following procedure was used to prepare several
filterable composite adsorbents for evaluation. In each case, a
sodium silicate solution with a SiO.sub.2:Na.sub.2O weight ratio of
3.2 to 1 was selected based on a combination of efficiency and
price, but other ratios of SiO.sub.2:Na.sub.2O may also be used.
The sodium silicate was added to reverse osmosis water with a
concentration of about 2%. A quantity of sulfuric acid
(H.sub.2SO.sub.4) was then added to the slurry to reduce the pH to
about 5.5 to 9. A filtration component was then added to the
solution. In this example, the filtration component was
Harborlite.RTM. 200, an expanded milled perlite with a permeability
of 0.29 Da and a wet density of about 14.0 lbs/ft.sup.3. The amount
of filtration component added was based upon the desired amount of
silica gel in the end chill-proofing filter-aid product. The slurry
was stirred until gelling occurred (about 25-60 minutes depending
upon the pH level). Next, water was added to disperse the gelled
slurry. The slurry was then filtered and the composite was washed
with water. Then, the filterable composite adsorbent was heated in
an oven, to evaporate any excess moisture, until a stable weight
was obtained.
[0088] Table 1 provides information regarding the performance of a
chill-proofing filter-aid manufactured by the process described
above. Harborlite.RTM. 200 was used as the filtration component and
different amounts of silica gel were attached thereto by
precipitating diatomite based sodium silicate onto the filtration
component by varying the pH of the slurry. The control was a simple
mixture comprising 90% of Harborlite.RTM. 200 and 10% of Millennium
Chemical XP103.RTM. silica gel. The particle size of the adsorbent
components were smaller than the adsorbent particle size of the
control sample. As can be seen from Table 1, the turbidity of the
filtered fluid was lower after the fluid had been processed through
the filterable composite adsorbent compared to processing with
either the simple mixture of the control or a process that
incorporates no chill-proofing.
TABLE-US-00001 TABLE 1 Perlite-based filterable composite adsorbent
using DE-based sodium silicate Silica gel Reaction WD Perm. BET
S.A. % pH lb/ft.sup.3 Darcies m.sup.2/g NTU Harborlite .RTM. 10 7.7
14.9 0.54 41.2 4.2 200 Harborlite .RTM. 17 7.8 16.0 0.35 68.3 4.3
200 Harborlite .RTM. 0 -- 14.9 0.29 -- -- 200 Control 10 -- -- --
-- 7.2 Blank -- -- -- -- -- 34.3
Example 2
[0089] The procedure of Example 1 was repeated, except that Celite
Standard Super-Cel.RTM. and Celite Hyflo Super-Cel.RTM. were used
as filtration components in the place of the Harborlite.RTM. 200.
Celite Standard Super-Cel.RTM. filtration component is a
diatomite-based filtration component with a permeability of 0.25 Da
and a wet density of about 9 lbs/ft.sup.3. Celite Hyflo
Super-Cel.RTM. filtration component is also diatomite based, but
has a permeability of 1.10 Da and a wet density of 10
lbs/ft.sup.3.
[0090] Table 2 shows the filtration properties of a diatomite-based
chill-proofing filter-aid using different amounts of silica gel and
at different pH levels. The base materials were Celite Hyflo
Super-Cel.RTM. and Celite Standard Super-Cel.RTM. diatomite. It is
shown that the relative amount of silica gel precipitated upon the
filtration component had a direct relationship with the BET surface
area of the adsorbent component.
[0091] Table 3 shows the performance of a diatomite based
chill-proofing aid of Table 2. The filterable composite adsorbent
was more effective than either the simple mixture of the control or
a process that involves no chill proofing as evidenced by the low
turbidity values of the filtered fluid.
[0092] Table 4 shows the performance of diatomite based
chill-proofing filter-aid using Celite Standard Super-Cel.RTM. from
Table 2 with different amounts of silica gel attached thereto by
precipitating diatomite based sodium silicate onto the filtration
component by varying the pH of the slurry. The control was a system
simple mixture of 90% of Celite Standard Super-Cel.RTM. and 10% of
Millennium Chemicals XP103.RTM. silica gel. Again, the filterable
composite adsorbent as disclosed herein provided a superior value
than either the control system or the system which implemented no
chill-proofing measures.
TABLE-US-00002 TABLE 2 Filtration properties of DE-based filterable
composite adsorbent using DE-based sodium silicate Rxn. WD Perm BET
S.A. Silica gel % pH lb/ft.sup.3 Darcies m.sup.2/g Celite Hyflo
Super-Cel .RTM. 10 7.78 19.2 1.66 72.8 10 7.45 20.1 1.39 78.5 7.5
6.75 19.5 1.63 63.5 5 7.20 19.5 1.56 40.1 21.5 0.71 1.7 10 7.42
18.1 0.52 83.0 Celite Standard Super-Cel .RTM. 7.5 7.20 18.1 0.55
58.0 7.5 7.25 18.1 0.51 59.0 5 7.22 18.8 0.28 39.6 21.5 0.21
3.4
TABLE-US-00003 TABLE 3 Chill-haze removal by filterable composite
adsorbent ("FCA") formed by Celite Hyflo Super-Cel .RTM. and
DE-based sodium silicate Silica Gel Control* 10% 10% 10% Blank FCA
(g/100 mL) 0.6 0.6 0.6 0.6 0 NTU Average 35.5 26.25 27.65 30.1 56.1
pH 6.38 6.66 7.10 --
TABLE-US-00004 TABLE 4 Chill-haze removal by filterable composite
adsorbent ("FCA") formed by Celite Standard Super-Cel .RTM. and
DE-based sodium silicate Silica Gel Control* 10% 7.5% Blank FCA
(g/100 mL) 0.6 0.6 0.6 0 NTU Average 34.6 32.8 21.1 74.5 pH 7.42
7.20 --
Example 3
[0093] The procedure of Example 2 was repeated with the exception
of replacing the sodium silicate solution used in Example 2 with a
commercial sodium silicate solution. Again, different filtration
components were used in the process to create the filterable
composite adsorbent (Celite Standard Super-Cel.RTM., Celite Hyflo
Super-Cel.RTM., and Celite 512.RTM.).
[0094] Tables 5-8 show the performance of a commercial
non-diatomite based sodium silicate. In Tables 5-7, the commercial
sodium silicate solution used was PQ N-Clear.RTM., manufactured by
PQ Corporation of Valley Forge, Pa. PQ N-Clear.RTM. has a
SiO.sub.2:Na.sub.2 ratio of 3.22:1 and a pH of 11.3. In Table 8,
the commercial sodium silicate solution used was PQ N.RTM.,
manufactured by PQ Corporation of Valley Forge, Pa. Table 5
reflects a chill-proofing filtration component formed by Celite
Hyflo Super-Cel.RTM.. Table 6 reflects Celite Standard
Super-Cel.RTM. as the filtration component. Table 7 reflects Celite
512.RTM. as the filtration component. Celite 512.RTM. has a
permeability of 0.50 Da and a wet density of about 9 lbs/ft.sup.3.
For each case, the control comprised a simple mixture 90% Celite
Standard Super-Cel.RTM. and 10% Millennium Chemical XP103.RTM.
silica gel.
TABLE-US-00005 TABLE 5 Chill-haze removal by filterable composite
adsorbent ("FCA") formed by Celite Hyflo Super-Cel .RTM. and PQ's
N-Clear .RTM. sodium silicate Silica Gel Control 7.5% 7.5% 7.5%
7.5% 7.5% 10% 10% Blank FCA 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0 (g/
100 mL) NTU 39.8 31.2 42.7 28.6 28.4 42.5 27.6 29.8 89.3 Aver- age
pH 5.62 7.52 7.56 7.23 6.41 7.69 6.91
TABLE-US-00006 TABLE 6 Chill-haze removal by filterable composite
adsorbent ("FCA") formed by Celite Standard Super-Cel .RTM. and
PQ's N-Clear .RTM. sodium silicate Silica Gel Control 7.5% 7.5% 10%
10% Blank FCA (g/100 mL) 0.6 0.6 0.6 0.6 0.6 0 NTU Average 20.5
18.8 23.6 15.2 19.5 63.0 pH 6.61 7.64 6.72 7.21
TABLE-US-00007 TABLE 7 Chill-haze removal by filterable composite
adsorbent ("FCA") formed by Celite 512 .RTM. and PQ's N-Clear .RTM.
sodium silicate Silica Gel Control 7.5% 7.5% 8.8% 10% 10% 10% Blank
FCA 0.6 0.6 0.6 0.6 0.6 0.6 0.6 0 (g/100 mL) NTU 20.5 24.1 24.1
22.9 16.6 24.1 23.4 63.0 Average pH 7.56 6.23 7.56 7.68 7.48
7.56
TABLE-US-00008 TABLE 8 Chill-haze removal by filterable composite
adsorbent ("FCA") formed by PQ's N .RTM. sodium silicate Silica Gel
Celite Standard Celite Hyflo Control Super-Cel .RTM. Celite 512
.RTM. Super-Cel .RTM. Silica gel content 10% 7.5% 7.5% 7.5% FCA
(g/100 mL) 0.6 0.6 0.6 0.6 NTU Average 26.2 18.0 24.7 25.6 pH 7.45
7.5 7.45
Example 4
[0095] A filterable composite adsorbent was made using a Celite
Standard Super-Cel.RTM. and diatomite based sodium silicate. 43 g
of sodium silicate solution (containing 6.75 g of dissolved silica)
was added to 450 g of water. Next, 3.16 g of sulfuric acid (98%)
was added to the solution to reduce the solution pH to 7.2. The
filtration component (Celite Standard Super-Cel.RTM.) was then
added to the solution. The slurry was stirred for 37 minutes at
which time the slurry began to gel. 150 mL of water was added to
disperse the gelled slurry. Then the slurry was filtered and the
slurry cake was repeatedly washed with 300 mL of water. Finally,
the cake was then dried by heating it at 110.degree. C. for three
hours.
Example 5
[0096] The procedure of Example 1 was repeated to form a number of
filterable composite adsorbent compositions except that
Filter-Cel.RTM. was used as the filtration component in the place
of the Harborlite.RTM. 200. Different amounts of silica gel were
attached thereto by precipitating diatomite based sodium silicate
onto the filtration component by varying the pH of the slurry. The
resultant filterable composite adsorbents ranged in make-up from
7.5% by weight silica gel to 70% by weight silica gel. In addition,
the filterable composite adsorbents were then treated by
pulverization to vary the particle size of the filterable composite
adsorbent compositions from a d50 of 19 microns to a d50 of 39
microns.
[0097] Next, the filterable composite adsorbents were mixed with a
second filtration component, Celite 512Z.RTM., such that the
resultant filter aid materials comprised 35% by weight filterable
composite adsorbent and 65% by weight of Celite 512Z.RTM..
[0098] Table 9 provides information regarding the performance of
the filter-aid materials as chill-proofing filter-aids. The
filter-aids were used to filter beer at a rate of 0.6 grams per 100
grams of beer. Three trials were run with each filter-aid material
with the chill haze, chill haze average, and chill haze standard
deviation being recorded. The filter-aids according to this example
were compared with the performance of a control comprising a simple
mixture of 65% by weight Celite 512Z.RTM. and 35% by weight of
Brightsorb d-300.RTM. (a conventional chillproofing silica
gel).
[0099] In the foregoing examples and Tables, the term "FCA" is used
to represent a filterable composite adsorbent, the term
"Brightsorb" is used to represent the adsorbent component
Brightsorb d-300.RTM., the term "SG" is used to represent the
adsorbent component silica gel, the term "C512Z" is used to
represent the filtration component Celite 512Z.RTM., the term "FC"
is used to represent the filtration component Filter Cel.RTM., the
term "C289" is used to represent the filtration component Celite
289.RTM., and the term "d50" is used to represent median particle
size in microns. In addition, the filterable composite adsorbents
may be represented by a short sequence comprising (filtration
component-adsorbent component (#% by weight adsorbent component)).
For example, "C512Z-SG70" represents a filterable composite
adsorbent wherein the filtration component is Celite 512Z.RTM., the
adsorbent component is silica gel, and the silica gel comprises 70%
by weight of the filterable composite adsorbent.
TABLE-US-00009 TABLE 9 Filtration properties of filter-aid
materials comprising Celite 512Z .RTM. and a filterable composite
adsorbent comprising Filter Cel .RTM. as the filtration component
Filterable Filter-Aid Material Chill Haze Chill Haze Chill Haze
Composite Comprising Mixture (NTU) Average St. Dev. Adsorbent
("FCA") of FCA with C512Z 1 2 3 (NTU) (NTU) Control Brightsorb 35%:
59.2 59.7 64 61.0 2.64 C512Z 65% C512Z-SG7.5 C512Z-SG7.5 100% 79.2
72.5 76.6 76.1 3.38 (d50 = 22) C512Z 0% FC-SG70 FC-SG70 35%: 78.5
86.8 76.6 80.6 5.42 (d50 = 39) C512Z 65% FC-SG70 FC-SG70 35%: 56.2
57.7 59.3 57.7 1.55 (d50 = 32) C512Z 65% FC-SG70 FC-SG70 35%: 74.6
59.6 62.0 65.4 8.06 (d50 = 27) C512Z 65% FC-SG70 FC-SG70 35%: 60
62.6 69.7 64.1 5.02 (d50 = 25) C512Z 65% FC-SG45 FC-SG45 35%: 74.5
78.2 82.1 78.3 3.80 (d50 = 22) C512Z 65% FC-SG7.5 FC-SG7.5 35%:
82.1 92.7 93.3 89.4 6.30 (d50 = 19) C512Z 65%
[0100] As shown by Table 9, the effectiveness of the filter-aid
materials' adsorbency generally increased with an increase in the
adsorbent component in the filterable composite adsorbent
component. In addition, the effectiveness of the filter-aid
materials' adsorbency generally increased with a decrease in
particle size due to pulverization. It is believed that
pulverization leads to an increased amount of silica gel sites,
thus leading to the improved adsorbency.
Example 6
[0101] The procedure of example 5 was repeated, except that the
filterable composite adsorbent did not undergo pulverization and
the proportion of the second filtration component (Celite
512Z.RTM.) to the filterable composite adsorbent was varied. The
surface area of the Celite 512Z.RTM. was measured as 55
m.sup.2/gram. The effect of the variance of the ratio of the second
filtration component to the filterable composite adsorbent on chill
haze and permeability are shown in tables 10 and 11. All trials
were aged for 75 hours except for those denoted with (*) which were
aged for 99 hours and chilled for 24 hours.
TABLE-US-00010 TABLE 10 Filtration properties of filter-aid
materials comprising Celite 512Z .RTM. and a filterable composite
adsorbent comprising Filter Cel .RTM. as the filtration component
Chill Haze 2nd Filtration Overall (NTU) Chill Haze Chill Haze Trial
FCA % Component % SG % 1 2 3 Average St. Dev. Brightsorb Celite
512Z 1 0 100 0 262 270 266.0 5.7 2 35 65 35 28.5 25.6 25.2 26.4 1.8
3* 100 0 100 13.5 15.7 11.7 13.6 2.0 FC-SG70 Celite 512Z 4* 100 0
70 10.8 7.98 8.99 9.3 1.4 5 50 50 35 31.4 26.3 32.9 30.2 3.5 6 35
65 25 37.9 33.6 30.9 34.1 3.5 7 25 75 18 52 49.4 50.7 1.8 8 10 90
7.0 240 240 233 237.7 4.0 FC-SG45 Celite 512Z 9* 100 0 45 12.4 12.0
12.2 12.2 0.2 10 50 50 23 29.2 25.4 31.1 28.6 2.9 11 35 65 16 41.7
37.4 39.6 3.0 12 25 75 11 45.5 41.8 49.2 45.5 3.7 13 10 90 4.5 228
244 236.0 11.3 FC-SG7.5 Celite 512Z 14* 100 0 7.5 13.9 13.5 13.6
13.7 0.2 15 50 50 3.8 31.8 28.6 30.2 2.3 16 35 65 2.6 47.5 41.4
44.5 4.3 17 25 75 1.9 47.8 51.4 49.6 2.5 18 10 90 0.8 225 237 237
233.0 6.9
[0102] As can be seen from Tables 10 and 11, the filter-aid
materials of the present invention, and in particular that
identified by trial 6, were able to exhibit comparable adsorbency
when compared with the control (trial 2), however at lower
concentrations of silica gel by weight of the total filter aid.
Such a reduction in the requirement for the adsorbent component may
lead to a considerable cost advantage in production. In addition,
the filter-aid material of trial 6 was able to obtain comparable
adsorbency while exhibiting a significant increase in permeability
as compared to the control.
TABLE-US-00011 TABLE 11 Permeability properties of filter-aid
materials comprising Celite 512Z .RTM. and a filterable composite
adsorbent comprising Filter Cel .RTM. as the filtration component
Surface Area 2nd Filtration Overall of Filter Aid Permeability
Trial FCA % Component % SG % (m.sup.2/g) (Darcy) Brightsorb Celite
512Z 1 0 100 0 0.42 2 35 65 35 0.17 3* 100 0 100 FC-SG70 Celite
512Z 4* 100 0 70 161 very slow 5 50 50 35 0.16 6 35 65 25 0.27 7 25
75 18 8 10 90 7.0 FC-SG45 Celite 512Z 9* 100 0 45 173 very slow 10
50 50 23 11 35 65 16 0.18 12 25 75 11 13 10 90 4.5 FC-SG7.5 Celite
512Z 14* 100 0 7.5 94 very slow 15 50 50 3.8 16 35 65 2.6 0.14 17
25 75 1.9 18 10 90 0.8
Example 7
[0103] The procedure of Example 6 was repeated, except that the
filtration component of the filterable composite adsorbent was
changed from Filter Cel.RTM. to Celite 289.RTM.. The Celite
289.RTM. was measured as having a surface area of 35 m.sup.2/gram.
The effect of the variance of the ratio of the second filtration
component to the filterable composite adsorbent on chill haze and
permeability are shown in tables 12 and 13. All trials were aged
for 75 hours except for those denoted with (*) which were aged for
99 hours and chilled for 24.
TABLE-US-00012 TABLE 12 Filtration properties of filter-aid
materials comprising Celite 512Z .RTM. and a filterable composite
adsorbent comprising Celite 289 .RTM. as the filtration component
Chill Haze 2nd Filtration Overall (NTU) Chill Haze Chill Haze Trial
FCA % Component % SG % 1 2 3 Average St. Dev. Brightsorb Celite
512Z 19 0 100 0 303 287 294 294.7 8.0 20 35 65 35 23.0 22.6 25.9
23.8 1.8 21* 100 0 100 12.5 12.8 13.8 13.0 0.7 C289-SG70 Celite
512Z 22* 100 0 70 8.46 8.42 9.18 8.7 0.4 23 50 50 35 24.4 26.2 25.5
25.4 0.9 24 35 65 25 35.2 39.5 36.6 37.1 2.2 25 25 75 18 250 254
267 257.0 8.9 26 10 90 7.0 271 277 281 276.3 5.0 C289-SG45 Celite
512Z 27* 100 0 45 28.2 27.2 24.8 26.7 1.7 28 50 50 23 45.2 47 38.1
43.4 4.7 29 35 65 16 50.8 51.9 51.8 51.5 0.6 30 25 75 11 250 250
258 252.7 4.6 31 10 90 4.5 271 270 276 272.3 3.2 C289-SG7.5 Celite
512Z 32* 100 0 7.5 23.4 21.3 22.2 22.3 1.1 33 50 50 3.8 46.0 44.5
44.0 44.8 1.0 34 35 65 2.6 55 227 248 176.7 105.9 35 25 75 1.9 220
271 270 253.7 29.2 36 10 90 0.75 270 281 306 285.7 18.4
TABLE-US-00013 TABLE 13 Filtration properties of filter-aid
materials comprising Celite 512Z .RTM. and a filterable composite
adsorbent comprisin Celite 289 .RTM. as the filtration component
Surface Area of 2nd Filtration Overall Filter Aid Permeability
Trial FCA % Component % SG % (m2/g) (Darcy) Brightsorb Celite 512Z
19 0 100 0 0.42 20 35 65 35 0.17 21* 100 0 100 C289-SG70 Celite
512Z 22* 100 0 70 216 very slow 23 50 50 35 24 35 65 25 0.15 25 25
75 18 26 10 90 7.0 C289-SG45 Celite 512Z 27* 100 0 45 135 very slow
28 50 50 23 29 35 65 16 0.19 30 25 75 11 31 10 90 4.5 C289-SG7.5
Celite 512Z 32* 100 0 7.5 80 very slow 33 50 50 3.8 34 35 65 2.6
0.11 35 25 75 1.9 36 10 90 0.75
Example 8
[0104] The procedure of Example 6 was repeated, except that the
filterable composite adsorbent was changed from Filter Cel.RTM. to
Celite 512Z.RTM.. The Celite 512Z.RTM. was measured as having a
surface area of 3 m.sup.2/gram. The effect of the variance of the
ratio of the second filtration component to the filterable
composite adsorbent on chill haze is shown in table 14. All trials
were aged for 75 hours except for those denoted with (*) which were
aged for 99 hours and chilled for 24.
TABLE-US-00014 TABLE 14 Filtration properties of filter-aid
materials comprising Celite 512Z .RTM. and a filterable composite
adsorbent comprising Celite 512Z .RTM. as the filtration component
Chill Haze Chill Chill Surface 2nd Filtration Overall (NTU) Haze
Haze Area Trial FCA % Component % SG % 1 2 3 Average St. Dev.
(m2/g) Brightsorb Celite 512Z 37 0 100 0 287 280 334 300 29.4 3 38
35 65 35 25.0 32 33 30.0 4.4 39* 100 0 100 12.5 12.8 13.8 13.0 0.7
C512Z-SG70 Celite 512Z 40* 100 0 70 19.8 20.9 21.4 14.8 0.8 272 41
65 35 46 27.1 28.2 31.1 28.8 2.1 42 50 50 35 33.1 39.4 40.9 37.8
4.1 43 35 65 25 240 220 253 238 16.6 44 10 90 C512Z-SG45 Celite
512Z 45* 100 0 45 15.4 14 14.9 20.7 0.7 139 46 80 20 36 38 38 38.0
0.0 47 50 50 23 263 248 256 10.6 48 35 65 16 274 285 280 7.8 49 10
90 C512Z-SG7.5 Celite 512Z 50* 100 0 7.5 28.8 30.1 27.2 28.7 1.5
48
[0105] As can be seen from the preceding Tables 10-14, the
filter-aid materials according to the instant invention's
adsorbency generally increased with an increase in the surface area
of the filtration component of the filterable composite adsorbent.
It is believed that a high surface area of the filtration component
of the filterable composite adsorbent reduces the thickness of the
silica gel coating and thereby providing more sites for adsorption
of the chill haze particles.
Example 9
[0106] The procedure of Example 5 was repeated to form a number of
filter-aid materials comprising a filterable composite adsorbent,
except that the filterable composite adsorbent did not undergo
pulverization and, in half of the materials, Celite 289 was used as
the filtration component in the place of Filter-Cel.RTM.. The
filter-aid materials were then used in a beer filtration process to
analyze the wet density and permeability of those mixtures. The
results are shown in table 15. Trials 51, 52, 58, and 59 were the
controls.
TABLE-US-00015 TABLE 15 Wet density and permeability properties of
filter-aid materials comprising Celite 512Z .RTM. and a filterable
composite adsorbent comprising either Celite 512Z .RTM. or Filter
Cel .RTM. as the filtration component Wet FCA FCA FCA Density
Permeability Trial C512Z Brightsorb FC-SG7.5 FC-SG45 FC-SG70
(lb/ft3) (Darcy) 51 100 0 0 0 0 22.3 0.42 52 65 35 0 0 0 20.8 0.17
53 0 0 100 0 0 Very slow 54 65 0 35 0 0 19.5 0.14 55 65 0 0 35 0
21.2 0.18 56 65 0 0 0 35 23.1 0.27 57 50 0 0 0 50 24.0 0.16 C512Z
Brightsorb C289-SG7.5 C289-SG45 C289-SG70 58 100 0 0 0 0 22.3 0.42
59 65 35 0 0 0 20.8 0.17 60 0 0 100 0 0 Very slow 61 65 0 35 0 0
20.1 0.11 62 65 0 0 35 0 21.2 0.19 63 65 0 0 0 35 23.1 0.15
[0107] As can be seen by Table 15, the filter-aid materials
comprising a filterable composite adsorbent of the present
invention demonstrate permeabilities which are comparable to, and
in many cases better than, the permeability exhibited by one of the
controls (Trial 52).
* * * * *