U.S. patent application number 11/774222 was filed with the patent office on 2007-10-25 for reactive-adsorptive protective materials and methods for use.
Invention is credited to HOLLY C. AXTELL, Scott M. Hartley, Sallavanti Robert A..
Application Number | 20070248529 11/774222 |
Document ID | / |
Family ID | 27766180 |
Filed Date | 2007-10-25 |
United States Patent
Application |
20070248529 |
Kind Code |
A1 |
AXTELL; HOLLY C. ; et
al. |
October 25, 2007 |
REACTIVE-ADSORPTIVE PROTECTIVE MATERIALS AND METHODS FOR USE
Abstract
A reactive-adsorptive protective material having an activated
carbon adsorbent, including those manufactured from a gel-type ion
exchange resin. The activated carbon adsorbent has adsorptive
properties for adsorbing chemical impurities. The activated carbon
is wettlerized to further impart reactive properties onto the
activated carbon for providing protection against blood agents in
the atmosphere. Advantageously, a superior reactive-adsorptive
material is provided having the ability to neutralize chemical
substances, in particular, blood agents, while at the same time not
diminishing the effectiveness of the carbon's adsorption
capabilities.
Inventors: |
AXTELL; HOLLY C.;
(Factoryville, PA) ; Hartley; Scott M.; (Clarks
Summit, PA) ; Robert A.; Sallavanti; (Dalton,
PA) |
Correspondence
Address: |
KEUSEY, TUTUNJIAN & BITETTO, P.C.
20 CROSSWAYS PARK NORTH
SUITE 210
WOODBURY
NY
11797
US
|
Family ID: |
27766180 |
Appl. No.: |
11/774222 |
Filed: |
July 6, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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10372352 |
Feb 24, 2003 |
7256156 |
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11774222 |
Jul 6, 2007 |
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60360050 |
Feb 25, 2002 |
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Current U.S.
Class: |
423/460 |
Current CPC
Class: |
B01J 20/28014 20130101;
B01J 20/28009 20130101; B01J 20/28057 20130101; A61P 43/00
20180101; B01J 20/28023 20130101; B01J 20/28019 20130101; Y10S
977/777 20130101; Y10S 977/779 20130101; Y10T 442/2525 20150401;
B01J 20/28028 20130101; A61K 33/02 20130101; A62D 5/00 20130101;
B01J 20/041 20130101; B01J 20/28078 20130101; B01J 20/3204
20130101; Y10T 156/1089 20150115; B01J 20/06 20130101; B01J
20/28092 20130101; B01J 20/20 20130101; Y10S 977/881 20130101; B01J
20/28052 20130101; B01J 20/3236 20130101; B01J 20/3295 20130101;
B01J 20/28007 20130101; B01J 20/28038 20130101; B01J 20/28011
20130101; B01J 20/28097 20130101; B01J 20/3293 20130101; B82Y 30/00
20130101; B01J 20/28088 20130101 |
Class at
Publication: |
423/460 |
International
Class: |
C09C 1/56 20060101
C09C001/56 |
Claims
1. A method of providing a reactive-adsorptive protective material
for combating chemical or biological threats comprising the steps
of: providing adsorptive carbon that has been activated to produce
a Brunauer-Emmett-Teller (BET) surface area of at least 1500
m.sup.2/g and a pore size distribution having a majority of the
pores below 40 .ANG.; and providing finely-divided inorganic metal
oxide nanoparticulates that agglomerate into 1 nm to 200 nm sized
clusters due to van der Waals forces, whereby the clusters have a
BET surface area of at least about 1200 m.sup.2/g; and imbedding
the agglomerated clusters directly onto the activated carbon by (i)
controlling the forces to minimize over occlusion and preserve
adsorptive surface area and (ii) avoiding chemical reactions to
retain the nanoparticulate's reactive properties to provide a
reactive-adsorptive protective material; wherein the
reactive-adsorptive protective material is adapted to combat
chemical or biological threats contained within an environment,
without interfering with the activated carbon adsorbent's ability
to combat an adsorbable threat.
2. The method of claim 1, wherein the activated carbon has a
substantially spherical shape.
3. The method of claim 1, wherein the activated carbon has a
microstructure with pores in a size range between 0 .ANG. and 40
.ANG., wherein 5% to 10% of the overall micropore volume includes
pores between 20-40 .ANG.; 15% to 25% of the overall micropore
volume includes pores between 10-20 .ANG.; 0% to 20% of the overall
micropore volume includes pores between 8-10 .ANG.; 40% and 50% of
the overall micropore volume includes pores between 5-8 .ANG.; and
10%-25% of the overall micropore volume includes pores smaller than
5 .ANG..
4. The method of claim 3, wherein the pore density in the
microstructure is at least 0.6 cm.sup.3/g.
5. The method of claim 1, wherein the activated carbon bead is
produced from the gel-type ion exchange resin by: delivering the
gel-type ion exchange resin to a rotary tunnel dryer pre-heated to
from 880.degree. to 900.degree. C. up to a filling volume of from
10 to 20%, wherein a product temperature of from 250.degree. to
300.degree. C. is set up in the dryer in the 50 to 80% kiln length
range, said kiln length range being calculated from the product
input; drying the gel-type ion exchange resin continuously with
6-fold product turnover per kiln rotation and a residence time of
from 30 to 60 minutes by means of a hot gas in countercurrent to a
residual moisture content of at least 10%; transferring the
gel-type ion exchange resin to an indirectly heated rotary tunnel
kiln up to a filling volume of from 5 to 10%, said indirectly
heated rotary tunnel kiln having a carbonizing zone and an
activating zone, wherein the gel-type on exchange resin is
carbonized and activated continuously in an inert-gas flow with
8-fold product turnover per kiln rotation and with a product
temperature profile in the carbonizing zone of from 850.degree. to
900.degree. C. and a residence time of from 120 to 180 minutes, and
with a product temperature profile in the activating zone of from
910.degree. to 920.degree. C. and a residence time of from 480 to
720 minutes with the addition of from 3 to 5 kg/hkg of steam in the
activating zone.
6. The method of claim 5, wherein the flow-rate of the hot gas in
the dryer, expressed in terms of free cross-section, is from 0.2 to
0.5 m/s, with a kiln length to kiln diameter ratio of from 5.5 to
10.
7. The method of claim 6, wherein the carbonizing zone covers 20%
and the activating zone covers 80% of the heated kiln length,
calculated from the product input; and wherein the carbonizing
takes place with a product temperature profile, calculated in terms
of the heated kiln length from the product input, of 850.degree. C.
at the product input, 880.degree. C. after 10% of the kiln length
and 900.degree. C. after 20% of the kiln length.
8. The method of claim 1, further comprising the step of sieving
the protective nanoparticles during said imbedding step.
9. The method of claim 1, wherein said embedding step comprises
electromagnetically induced impacting.
10. The method of claim 9, further comprising the step of sieving
the protective nanoparticles during impacting.
11. The method of claim 1, wherein said finely-divided inorganic
metal oxide nanoparticulates are selected from the group consisting
of chemically adsorptive nanoparticles, chemically reactive
nanoparticles, biocidally reactive nanoparticles, and combinations
thereof.
12. The method of claim 11, wherein said finely-divided inorganic
metal oxide nanoparticulates are selected from the group consisting
of metal oxides, metal hydroxides, metal hydrates, POMs, and
combinations thereof.
13. The method of claim 11, wherein said finely-divided inorganic
metal oxide nanoparticulates are combined with a material selected
from the group consisting of a metal oxide, a reactive halogen, an
alkali metal, a metal nitrate, SO.sub.2, NO.sub.2, ozone, and
combinations thereof.
14. The method of claim 11, wherein said nanoparticulates have an
average pore radius of at least about 45 Angstroms to at least
about 100 Angstroms.
15. The method of claim 1, further comprising the steps of: loading
metal ions onto activated carbon adsorbents, prior to said
imbedding step, whereby the metal ions are adapted to combat blood
agent threats contained within the environment, without interfering
with the activated carbon adsorbent's ability to combat an
adsorbable chemical threat.
16. The method of claim 15, wherein the adsorbents derive from a
gel-type resin.
17. The method of claim 15, wherein said step of loading includes
one of infusing metal ions, perfusing metal ions and wettlerizing
metal ions.
18. The method of claim 15, wherein the metal ions are selected
from the group consisting of zinc, copper and molybdenum.
19. The method of claim 15, wherein the nanoparticulates are
combined with a reactive halogen.
20. The method of claim 1, wherein the nanoparticulates are
selected from the group consisting of finely-divided inorganic
metal-containing nanoparticles combined with a reactive halogen,
finely-divided inorganic metal-containing nanocrystals,
finely-divided inorganic metal-containing nanocrystals combined
with a reactive halogen, and combinations thereof.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This utility application is a continuation of U.S. patent
application Ser. No. 10/372,352 filed on Feb. 24, 2003 which claims
the priority date benefit of U.S. Provisional Application
60/360,050 filed on Feb. 25, 2002.
BACKGROUND OF THE INVENTION
[0002] 1. Technical Field
[0003] The present invention relates generally to protective
materials, and in particular, to reactive and adsorptive materials
for providing protection from chemical agents and blood agents and
methods for providing and using such materials. Also, these
materials may be further treated to provide protection from
biological agents.
[0004] 2. Description of Related Art
[0005] Agents of chemical warfare have existed for a long time and
can generally be grouped into the following three classes: 1)
blister/percutaneous agents 2) nerve agents, and 3) blood
agents.
[0006] 1) Blister/percutaneous agents attack the skin and/or mucous
membrane tissues external or internal to the human body, including
the inhalation route. The resulting blistering and ulceration is
extremely debilitating and can be fatal. Typical of this class is
Mustard (labeled as Agent HD) which can be present as a liquid or a
gas or within an aerosolized carrier.
[0007] These agents were found early on to be readily adsorbed by
activated carbon which, when contained within canister beds or
immobilized/fixed within or upon various textile substrates,
offered the ready capability to adsorb such agents and hold them
away from vulnerable body areas of the person to be protected.
Activated carbon has been made into and presented as powders,
granules, dried slurries, fibers, spherical beads, etc. and is
derived from a variety of processes which are performed on organic
precursors such as coconut husks, wood, pitch and organic resins.
Each process is unique but can be reduced in view to the following
steps. (a) carbonizing the organic precursor material to carbon of
modest internal surface area (of the order of tens to a few hundred
of square meters or surface area per gram of carbon), and then (b)
activating this carbon to produce a carbon with many hundreds to
low thousands of n.sup.2/gm of surface area. Such activated carbon
has strong adsorptive abilities. When a material adsorbs something,
it means that it attaches to it by chemical attraction. The huge
surface area of activated carbon gives it countless bonding sites.
When certain chemicals pass next to the carbon surface they attach
to the surface and are trapped.
[0008] The carbons materials must be fixed within or upon a carrier
substrate in order to be rendered into a useful form. Such
fixation, whether by way of adhesion or entrapment or some other
mode of fixing the carbon on the carrier, must be done deftly
enough such that as little as possible of the valuable surface area
is obfuscated by the fixation process.
[0009] 2) The nerve agents are a variety of compounds which can be
presented as gases, liquids or secured either in aerosol or other
carriers, much as is HD. They attack the human body and interfere
with nervous system functioning via immobilization of key enzymes
necessary therein, causing death or severe injury. They all operate
principally via percutaneous and inhalation routes and are
extremely toxic even in miniscule amounts. Typical of such species
are Sarin and Soman, often referred to as the G agents (GB and GD).
They are also efficiently adsorbed by carbon of high surface area
with the same carbon source/process and fixation considerations as
discussed above.
[0010] 3) The blood agents are those species which, when inhaled,
dissolve via the lungs in the blood and cause asphyxiation by
displacing the oxygen (O.sub.2) normally carried by the hemoglobin
moieties with more potently binding species known as strong Lewis
Bases. Such agents include Hydrogen Cyanide (HCN), Carbon Monoxide
(CO), Phosgene (COCl.sub.2) and others. The blood agents are
minimally and essentially ignorably adsorbed by the activated
carbon spoken of above. This is because the blood agents constitute
molecules of too low a molecular weight such that their fugacity at
normal temperatures exceeds any surface bonding power which the
activated carbon can offer. Indeed, although activated carbon is
useful for trapping carbon-based impurities ("organic" chemicals),
as well as elements like chlorine, many other chemicals (sodium,
nitrates, etc.) are not attracted to carbon at all, and therefore
pass through unadsorbed. Thus, an activated carbon filter will
remove only certain impurities while ignoring others.
[0011] It is to be noted that there are some chemical agents which
can arguably be either percutaneous, inhalation or blood agents, or
some combination of these simultaneously. However, for the purposes
mentioned herein, such species would operationally fall into one or
more of the modes of handling which are cited above.
[0012] Accordingly, there exists a need for materials which have
improved adsorptive properties for greater adsorption of impurities
and which also have reactive properties to concurrently and
effectively neutralize chemical substances which, for example,
cannot be adsorbed.
SUMMARY OF THE INVENTION
[0013] The present invention is directed to reactive and adsorptive
materials for providing protection from chemical and/or biological
agents and methods for providing such materials. Advantageously,
the present invention provides for efficient and effective
adsorption and neutralization of harmful chemical agents as well as
blood agents.
[0014] Specifically, activated carbon according to the present
invention advantageously retains an effective level of adsorptive
ability (i.e., the surface area of the bead is not measurably
diminished) despite being wettlerized (and/or imbedded with
nanoparticles). This is so because even after being imbedded with
metal ions and/or nanoparticles, an effective amount of pores in
the activated carbon remain unoccluded such that the adsorptive
properties of the carbon remain unaffected. This combination of
features advantageously results in a superior reactive-adsorptive
material having the ability to neutralize chemical substances
and/or kill biological agents while at the same time not
diminishing the effectiveness of the carbon's adsorptive
capabilities.
[0015] According to an aspect of the present invention, a
reactive-adsorptive protective material is provided comprising an
activated carbon bead manufactured from a gel-type ion exchange
resin, said activated carbon bead having pores for providing
adsorptive properties, and metal ions infused into said pores of
said activated carbon bead for imparting reactive properties onto
the activated carbon.
[0016] According to yet another aspect of the present invention, a
reactive-adsorptive protective material is provided comprising a
gel-type ion exchange resin carbonized and activated to fern
activated carbon having adsorptive properties, pores within said
carbon beads having a pore size distribution, and metal ions in
contact with said pores, wherein the activated carbon retains an
effective level of adsorptive ability.
[0017] According to yet another aspect of the present invention, a
method of providing a reactive-adsorptive protective material is
provided comprising the steps of producing activated carbon from a
gel-type ion exchange resin, the activated carbon having adsorptive
properties for adsorbing chemical impurities, and loading metal
ions onto the activated carbon to further impart reactive
properties onto the activated carbon for providing protection
against blood agents which are in contact therewith.
[0018] According to another aspect of the present invention, the
reactive-adsorptive materials according to the present invention
may further be imparted with reactive biocidal nanoparticles, as
per a process described in co-pending U.S. Patent Application
entitled "Multi-Functional Protective Materials and Methods for
Providing Same" filed concurrently herewith, bearing U.S. patent
application Ser. No. 10/372,527. The complete disclosure of this
concurrently filed application is hereby incorporated by reference.
For example, either an improved activated carbon bead according to
the present invention by itself and/or an improved activated carbon
bead that has been wettlerized can further be subjected to an
electromagnetically induced impaction process in combination with
simultaneous sieving so as to imbed nanoparticular agglomerated
entities into the surface of the beads where they are held in place
by the topographical imbedding in the carbon bead and the van der
Waals forces between the particle ions and the carbon beads'
surface/pore atoms proximate to the nanoparticle. Advantageously,
these imbedded nanoparticles impart additional protection by
destructively adsorbing chemicals and microorganisms. Specifically,
the nanoparticles are able to protect against biological agents by
destroying or inactivating microorganisms by attacking their cell
membranes and oxidizing important functional proteins or DNA. The
nanoparticle impaction process is further described in co-pending
U.S. patent application Ser. No. 10/372,527 mentioned above.
[0019] These and other aspects, features and advantages of the
present invention will be described or become apparent from the
following detailed description of the preferred embodiments, which
is to be read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 depicts an exemplary SEM micrograph of an untreated
carbon bead.
[0021] FIG. 2 depicts an exemplary SEM micrograph of a carbon bead
loaded with 1% MgO particles according to an aspect of the present
invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0022] An activated carbonaceous bead with extraordinarily high
surface area (e.g., .about.1500 m.sup.2/gm) and extraordinary
hardness (e.g., from about 2 to about 10 times harder than prior
art Rohm & Haas and Kureha beads) comprises the activated
carbon bead preferably used according to an aspect of the present
invention. The materials and methods used for manufacturing the
activated carbon bead used in the present invention are described
in published U.S. Patent Application No. 2002-0028333 entitled
"Spherical High Performance Adsorbents with Microstructure" by
Giebelhausen et al. filed on Mar. 8, 2001, U.S. Pat. No. 6,376,404
entitled "Process for the Production of Shaped High-Performance
Adsorbents" by Giebelhausen et al. filed on Mar. 15, 2000, and U.S.
Pat. No. 6,316,378 entitled "Process for the Production of Shaped
Activated Carbon" by Giebelhausen et al. filed on Mar. 15, 2000,
the disclosures of which are all incorporated herein by reference
thereto.
[0023] It is to be noted that the materials preferably used for
manufacturing the activated carbon used according to the present
invention preferably comprise spherical high-performance adsorbents
which are manufactured from polymer resin by water vapor activation
with an activation time of at least 6 hours. These adsorbents have
a pronounced microstructure in the range of about 0 .ANG. to about
40 .ANG. pore diameter and an overall micropore volume of at least
0.6 cm.sup.3/g. A substantial increase in the adsorption capacity
for gases and vapors is achieved which is also represented by the
very favorable ratio of weight capacity to volume capacity of up to
2 to 1. The spherical high-performance adsorbents with
microstructure can be used for many purposes, in particular,
textile fabrics for the adsorption of chemical warfare agents and
toxic gases and vapors, in adsorption refrigerating plants in
combination with the refrigerating agent methanol, in motor vehicle
filters and biofilters.
[0024] As used in the claims, the term "activated carbon adsorbent"
refers to any suitable form of activated carbon useful in
protective applications. By way of non-limiting examples, the
"activated carbon adsorbents" may take the form of beads, pellets,
powders, granules, grains, tablets, particulates, fibers or dried
slurries. A specific example having known utility is a bead having
a highly uniform spherical shape. The spherical high-performance
adsorbents preferably used in the present invention are explained
in further detail below by means of exemplified embodiments.
EXAMPLE 1
[0025] Initially, 3 kg of a carbonized spherical cation exchanger
polymer resin, sold under the designation Lewatit 1431, from Bayer
AG, Leverkusen, having the following quality specification is
selected as the starting material: TABLE-US-00001 Water content:
1.1% Volatile constituents: 1.5% Ash content 2.4% Fixed carbon:
96.1% Sulphur content: 15.0% Granulation: >1.25 mm 0.2% 1.25
mm-1.0 mm 5.1% 1.0 mm-0.8 mm 36.4% 0.8 mm-0.5 mm 56.1% <0.5 mm
2.2%
[0026] These gel-type resin beads are discontinuously activated for
7 hours in an inert gas flow in an indirectly heated tubular rotary
kiln, with the product being circulated 8 times per kiln rotation,
with the addition of 0.75 kg/hr water vapor at a low pressure on
the flue gas side of 0.1 mm water column and with a product
temperature of 920.degree. C., with respect to the overall heated
kiln length.
[0027] A total water vapor quality of 0.75 kg/hr is metered into
the activation kiln as follows: TABLE-US-00002 0.11 kg/hr water
vapour over 17% of the kiln length 0.15 kg/hr water vapour over 43%
of the kiln length 0.23 kg/hr water vapour over 54% of the kiln
length 0.15 kg/hr water vapour over 65% of the kiln length 0.11
kg/hr water vapour over 83% of the kiln length
[0028] The kiln length is measured from the bead input side. Then
the produced high performance adsorbents are cooled and screened as
grain fractions between 0.315 mm and 0.8 mm in size.
[0029] The spherical high-performance adsorbents used in the
present invention have a microstructure which is characterized by
the following pore distribution: TABLE-US-00003 pore pore diameter
volume pore volume content of overall micropore (in .ANG. Angstrom)
(in cm.sup.2/g) micropore volumes (in %) 40-20 0.031 5.0 20-10
0.114 18.7 10-8 0.09 14.8 8-5 0.249 40.8 5-0 0.126 20.7
[0030] The measurable dust content, i.e., grains smaller than 0.04
mm is less than 1%. The remaining grain-size distribution is as
follows: TABLE-US-00004 0.7-0.63 mm 0.2% 0.63-0.5 mm 12.3% 0.5-0.4
mm 78.2% 0.4-0.315 mm 9.3%
[0031] The spherical high-performance adsorbents used in the
present invention are characterized by the following quality
parameters specific to activated carbon: TABLE-US-00005 Settled
weight: 585 g/l Ash 1.9% Iodine value 1388 mg/g Methylene blue 28
ml BET surface 1409 m2/g Breaking strength 100% Dynamic hardness
100% Abrasion strength 100% Regeneration loss (after 10 1.5%
regeneration cycles)
[0032] Then, 500 g of the spherical high-performance adsorbents
according to the invention are applied to a textile fabric, so that
a high packing density is produced with a single-layer covering.
The efficiency of the high-performance adsorbents used is measured
in comparison with a test substance (reference substance for
chemical warfare agents) characterized by the adsorption speed
constant in accordance with the formula: ?=2.3 . . . 1 g
c.sub.0/c.sub.ta.sup.-1
[0033] a=weight of adsorbent sample
[0034] c.sub.t=concentration of the test substance after the
adsorption time
[0035] c.sub.0=initial concentration of the test substance
[0036] lg=logarithm
[0037] The measurement results in comparison with reference
products are given in Table 1: TABLE-US-00006 TABLE 1 Product
Adsorption speed constant ? PAX 500.sup.1) 3.2 HK 44.sup.2) 2.3
Ambersorb 572.sup.3) 2.1 .sup.1)PAK 500: sample of spherical
high-performance adsorbents with microstructure .sup.2)HK 44:
activated carbon on charcoal base .sup.3)Ambersorb 572: pyrolised
ion exchanger resin from Robm & Haas, USA
EXAMPLE 2
[0038] The suitability of the spherical high-performance adsorbents
for biofilter installations is tested in a laboratory bioreactor.
For this the product as given in Example 1 is filled into the
reactor chamber and immobilized with microorganisms up to a
charging of 3.7.times.10.sup.9 cells/g base material. Then 201/hr
moist exhaust air with a toluene concentration of 500 mg/m.sup.3
are conveyed over the immobilized high-performance adsorbents. The
achieved degradation capacity and the chamber charging with an
efficiency of 90% are represented in Table 4. TABLE-US-00007 TABLE
4 Degradation capacity chamber charging at 90% Product (in
g/m.sup.3 h) efficiency (in g/m.sup.3 h) PAK 500.sup.1) 12.4 39.6
WS IV.sup.2) 100.6 21.3 C 40/3.sup.3) 74.5 14.5 .sup.1)See Example
1 .sup.2)WS IV: formed activated carbon (4 mm) on a charcoal base
from Chemviron, Belgium .sup.3)C 40/3: formed activated carbon (3
mm) on a bituminous coal base according to the invention, CarboTex,
Germany
[0039] The infusion to Varying degrees of prior art carbon with
metal ions of the Transition Series in the Periodic Table is known.
The metal ions can be introduced in a variety of modes such that
the ions of the metals reside within the carbon (likely with the
metal cations' charges balanced by nearby spectator gegenions such
as oxide (O.sup.-2)). It is likely that these metallic ions bind
the blood agents via coordinate covalent ligand bonds. The metal
ions are strong Lewis acids--electron acceptors; while the agents
are strong Lewis bases--electron donors called ligands. When these
two encounter each other they bind strongly.
[0040] In addition, some blood agents are bound temporarily and
then decompose to species which become the bound ligands or which
can be adsorbed by the carbon. The process by which carbon is
perfused/infused with these metal ions is known somewhat
generically as "wettlerizing" and originally used ionic species
including ions of Chromium and Cadmium. With the recognition over
time that some of those metals were carcinogenic to varying
degrees, the metal mix presently used has preferably changed to
include ions of zinc, copper, molybdenum and others, while
excluding the more toxic metals. As used in the claims, the term
"loaded" means a perfusion process or an infusion process or a
wettlerization process to place metal ions on an activated carbon
adsorbent without affecting the adsorbent's ability to combat an
adsorbable chemical threat.
[0041] The activated carbon beads used in the present invention are
preferably further subjected to a wettlerization process to infuse
the proper transition metal ions into place within/onto the carbon
beads. Advantageously, the activated carbonaceous bead preferably
used according to an aspect of the present invention has, as
described above, both an extraordinarily high surface area (e.g.,
about 1500 m.sup.2/gm) and extraordinary hardness (e.g., from about
2 to about 10 times harder than Rohm & Haas and Kureha beads).
These carbon beads have the ability and capacity to take up these
metallic ions well in excess of previously tried carbon beads of
the prior art (e.g., Rohm & Haas and Kureha) while at the same
time not measurably diminishing either the surface area of the bead
or its hardness. Specifically, activated carbon according to the
present invention advantageously retains an effective level of
adsorptive ability (i.e., the surface area of the bead is not
measurably diminished) despite being wettlerized (and/or imbedded
with nanoparticles). This is so because even after being imbedded
with metal ions and/or nanoparticles, an effective amount of pores
in the activated carbon remain unoccluded such that the adsorptive
properties of the carbon remain unaffected. This combination of
features advantageously results in a superior reactive-adsorptive
material having the ability to neutralize chemical substances
and/or kill biological agents while at the same time not
diminishing the effectiveness of the carbon's adsorptive
capabilities.
[0042] Thus, a metal-ion-treated carbon bead according to the
present invention comprises a highly adsorptive bead which can also
react with and neutralize blood agents. Advantageously, the unique
surface area and pore distribution at the surface and within the
bead provide a hybrid product having unexpected, novel, useful and
unique abilities and very desirable properties. In particular, the
unique pore distribution of the carbon bead used according to the
present invention results in an especially effective overall
resultant product having an improved range of protective
properties. Specifically, the resultant product comprises a
material having both reactive properties for reacting with and/or
neutralizing chemical substances (e.g., blood agents) as well
adsorptive properties for adsorbing chemical impurities. This
reactive-adsorptive material preferably comprises an activated
carbon bead manufactured from a gel-type ion exchange resin,
wherein the bead is preferably further subjected to a
wettlerization process for introducing metal ions within and onto
the carbon bead to impart the reactive properties to the bead.
[0043] Whether the threat is chemical or biological and whether it
is presented as a liquid or a gas, the barrier which physically and
chemically protects the user (e.g., clothing, mask, filter, etc.)
is subjected to the following processes when in use: [0044] (1)
Molecules of gaseous chemical agent diffusing through the barrier
at some characteristic rate. [0045] (2) Liquid droplets of chemical
agent diffusing unaided or aided by some external pressure through
the barrier at some characteristic rate. [0046] (3) Biological
aerosolized microdroplets diffusing at some characteristic rate
through the barrier. [0047] (4) Carbon physically adsorbing organic
entities at some characteristic rate of adsorption. [0048] (5)
Iodinated resins or Nanoparticular entities reacting with
biological entities and their toxic residues in the latter case at
characteristic rates of reaction. [0049] (6) Entities within carbon
reacting with the very fugitive blood agents at some characteristic
chemical rate of reaction. [0050] (7) Normal safe air (O.sub.2 and
N.sub.2, for all practical purposes) and water vapor diffusing
through the barrier at their characteristic diffusion rates.
[0051] An ideal response to a chemical/biological threat is to
minimize (1), (2), and (3) while maximizing (4) through (7).
However, since these processes are coupled to each other, any
modestly successful approach walks a fine line to meet these
criteria.
[0052] It is to be noted that the reactive-adsorptive materials
according to the present invention may further be imparted with
reactive biocidal nanoparticles, as per a process described in
co-pending U.S. patent application Ser. No. 10/372,537. For
example, either an improved activated carbon bead according to the
present invention by itself as well as an improved activated carbon
bead that has been wettlerized can further be subjected to an
electromagnetically induced impaction process in combination with
simultaneous sieving so as to imbed nanoparticular agglomerated
entities into the surface of the beads where they are held in place
by the topographical imbedding in the carbon bead and the van der
Waals forces between the particle ions and the carbon beads'
surface/pore atoms proximate to the nanoparticle. Advantageously,
these imbedded nanoparticles impart additional protection by
destructively adsorbing chemicals and microorganisms. Specifically,
the nanoparticles are able to protect against biological agents by
destroying or inactivating microorganisms by attacking their cell
membranes and oxidizing important functional proteins or DNA. The
process by which the nanoparticles are loaded onto the carbon is an
electromagnetically assisted impact collision (MAIC) process which
is further described in co-pending U.S. patent application Ser. No.
10/372,537 mentioned above.
[0053] The nanoparticles preferably comprise environmentally stable
nanometer-sized clusters of atoms and molecules having high surface
areas and unique morphologies which result in high chemical
reactivity. The reactive/adsorptive particulates used according to
the present invention are preferably inorganic, reactive
nanoparticulates formed from about 1 nm to about 200 nm sized
clusters.
[0054] Reactive nanoparticles used for protective applications are
specifically engineered to destructively adsorb chemicals and
microorganisms. Specifically, a nanoparticle adsorbs then
detoxifies hazardous chemicals by breaking molecular bonds to yield
harmless end products. Similarly, the reactive/adsorptive
nanoparticles are able to kill or inactivate a microorganism by
attacking its cell membrane and oxidizing important functional
proteins or DNA.
[0055] Exemplary nanoparticles which may be used include metal
oxide composites in powder nanopartculate form. These metal oxide
composites comprise metal oxide nanoparticles having oxygen ion
moieties on their surfaces with reactive atoms interacted or
chemisorbed with those surface oxygen ions. For example, the metal
oxide nanoparticles may be taken from the group consisting of
oxides of Mg, Ti, Ca, Al, Sn, Fe, Co, V, Mn, Ni, Cr, Cu, Zn, Zr, or
mixtures thereof. For example, the metal oxide nanoparticles may
comprise MgO, TiO.sub.2, CaO, Al.sub.2O.sub.3, SnO.sub.2,
Fe.sub.2O.sub.3, FeO, CoO, V.sub.2O.sub.5, MnO.sub.3, NiO,
Cr.sub.2O.sub.3, CuO, ZnO, ZrO.sub.2 and mixtures thereof.
Nanoparticles made of metal complexes of hydroxides, metal
complexes of hydrates as well as polyoxometallates (POMs) are also
suitable. Some of the nanoparticles listed in this paragraph may
also be further processed, for example to include reactive halogen
atoms, alkali metal atoms, a metal nitrate, SO.sub.2, NO.sub.2,
ozone or a second different metal oxide. Alternate processing can
provide a protective coating to the nanoparticles which are not
soluble rendering them waterproof. These advanced processing steps
are disclosed in the following U.S. Pat. Nos., 6,057,488 and
5,914,436 and 5,990,373 and 5,712,219 and 6,087,294 and 6,093,236
and 5,759,939 and 6,417,423 and in Published U.S. Patent
Application Ser. No. 2002/0035032, the complete disclosures of
which are incorporated herein by reference thereto. Any of these
products may be incorporated into the multi-functional protective
products according to the invention.
[0056] The reactive/adsorbent nanoparticulates are thus
advantageously capable of;
[0057] a) Breaking down, decomposing or neutralizing chemicals
(e.g. reactive/adsorptive nanoparticulates)
[0058] b) Acting as a biocide, killing microorganisms
[0059] c) Neutralizing chemicals and simultaneously acting as a
biocide (e.g. reactive/adsorptive nanoparticulates such as MgO
nanoparticles, etc.). These nanoparticles may be enhanced or
modified for environmental purposes.
[0060] Thus, the nanoparticles preferably used according to the
present invention include at least one of chemically adsorptive
nanoparticles, chemically reactive nanoparticles, and biocidally
reactive nanoparticles. Further, the nanoparticles used according
to the present invention preferably have a Brunauer-Emnmett-Teller
(BET) multi-point surface area of at least about 70 m.sup.2/g for
older nanoparticles to at least about 1200 m.sup.2/g or more for
more advanced nanoparticles and have an average pore radius of at
least about 45 Angstroms to at least about 100 Angstroms.
[0061] In one example, Magnesium Oxide (MgO) nanoparticles in
concentrations of 0.5, 1.0 and 2.0% by weight were loaded onto
Ambersorb R-1500 carbon beads (produced by Rohm & Haas). For
comparative purposes and for use as a control, Ambersorb carbon was
processed in the MAIC system without the addition of nanoparticles.
Visual observations of die treated samples indicated good
attachment and distribution of the MgO on the Ambersorb carbon.
FIG. 1 depicts an exemplary SEM micrograph of an untreated
Ambersorb bead. FIG. 2 depicts an exemplary SEM micrograph of an
Ambersorb bead loaded with 1% MgO nanoparticles according to an
aspect of the present invention. This resultant treated particle
illustrated in FIG. 2 has the appearance of a spherical "cookie"
with "raisins" in its surface partially imbedded and partly
exposed.
[0062] The nanoparticles used in accordance with the invention are
those that possess a protective property, i.e. protective
nanoparticles or protective nanoparticulate entities. For purposes
of this application, the term "protective nanoparticles"
encompasses one or more of the following three particular types of
nanoparticles: chemically adsorptive nanoparticles; chemically
reactive nanoparticles; and biocidally reactive nanoparticles.
[0063] Protective nanoparticles are metal-containing nanoparticles
or metal-containing nanocrystals. The metals are present as metal
oxides, metal hydroxides, metal hydrates, POMs. To enhance their
protective properties, such metal-containing protectants may be
combined with one of more of a metal oxide, Group I metals, Group
IA metals, a reactive halogen, a metal nitrate, SO.sub.2, NO.sub.2,
or ozone.
[0064] It should be noted that a bulk metal-containing particle
that is ground down to a powder will not possess the protective
properties of the nanoparticles used according to the invention
because the ground powder will have conventional surface features.
In order to distinguish powders from nanoparticles which may be
seemingly in the same size range, the protectants according to the
invention are referred to as finely divided nanoparticles or finely
divided nanocrystals. Protective nanoparticles are formed from 1 nm
to 200 nm sized nanoparticulate clusters. These clusters cling
together due to van der Waals forces and therefore have many
distinguishable constituent parts. A ground powder is just a single
entity, with a uniform exterior surface. In contrast thereto, when
the nanometer sized clusters cling together much of their original
surface area is preserved providing Brunauer-Emmett-Teller (BET)
multi-point surface areas of at least 70 m.sup.2/g for early
protective nanoparticles and surface areas of at least 1200
m.sup.2/g for later versions. These surfaces may contain pores
having an average pore radius from 45 Angstroms to 100
Angstroms.
[0065] While the structure, surface area and pore size have imbued
the nanoparticles with their protective properties, these
structural features have also interfered with past attempts to
incorporate the nanoparticles into tangible protective filter
precursors. Failed attempts have resulted from an inability to
control the van der Waals forces resulting in excessive clumping or
from an inability to control the adhesive or retaining means
resulting in occluding of useful surface areas or pores. The
invention is concerned with products and methods that utilize
nanoparticles in a flexible manner to readily incorporate one or
more of their chemically adsorptive, chemically reactive or
biocidally reactive properties.
[0066] Although illustrative embodiments of the present invention
have been described herein, it is to be understood that the present
invention is not limited to those precise embodiments, and that
various other changes and modifications may be affected therein by
one skilled in the art without departing from the scope or spirit
of the present invention. For example, it is expressly intended
that all combinations of those carbon beads, metal ions and/or
method steps and/or substrate materials which perform substantially
the same function in substantially the same way to achieve the same
results are within the scope of the invention. Moreover, it should
be recognized that any disclosed form or embodiment of the
invention may be incorporated in any other disclosed or described
or suggested form or as a general matter of compatibility of
application method. It is the intention, therefore, to be limited
only as indicated by the scope of the claims appended hereto.
* * * * *