U.S. patent application number 14/347970 was filed with the patent office on 2014-11-06 for discharge solidifier and malodour control.
This patent application is currently assigned to CONVATEC LTD.. The applicant listed for this patent is Stewart Lee. Invention is credited to Stewart Lee.
Application Number | 20140330229 14/347970 |
Document ID | / |
Family ID | 44882103 |
Filed Date | 2014-11-06 |
United States Patent
Application |
20140330229 |
Kind Code |
A1 |
Lee; Stewart |
November 6, 2014 |
DISCHARGE SOLIDIFIER AND MALODOUR CONTROL
Abstract
An ostomy bag insert (104) comprising a polyacrylate
superabsorbent (300) and a powdered zeolite (301). The ostomy bag
insert is configured to absorb fluids excreted by the body and to
control odours resultant from the excreted matter within the ostomy
bag (100). The present zeolite exhibits enhanced odour control.
Inventors: |
Lee; Stewart; (Lancashire,
GB) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Lee; Stewart |
Lancashire |
|
GB |
|
|
Assignee: |
CONVATEC LTD.
Skillman
NJ
|
Family ID: |
44882103 |
Appl. No.: |
14/347970 |
Filed: |
August 31, 2012 |
PCT Filed: |
August 31, 2012 |
PCT NO: |
PCT/GB2012/052133 |
371 Date: |
July 15, 2014 |
Current U.S.
Class: |
604/333 ;
502/62 |
Current CPC
Class: |
A61L 28/0092 20130101;
A61L 28/0011 20130101; A61F 5/441 20130101; A61L 28/0003 20130101;
A61F 5/445 20130101 |
Class at
Publication: |
604/333 ;
502/62 |
International
Class: |
A61L 28/00 20060101
A61L028/00; A61F 5/441 20060101 A61F005/441 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 2, 2011 |
GB |
1115160.2 |
Claims
1. An ostomy bag insert comprising: a polyacrylate superabsorbent;
and a powdered zeolite; wherein the superabsorbent is coated with
the powdered zeolite.
2. The insert as claimed in claim 1 wherein the powdered zeolite
comprises a particle size equal to or less than 0.15 mm.
3. The insert as claimed in claim 1 wherein the zeolite comprises a
particle size equal to or less than 0.075 mm.
4. The insert as claimed in claim 1 wherein the zeolite comprises a
particle size of equal to or less than 0.045 mm.
5. The insert as claimed in claim 1 wherein the zeolite is a
zeolite blend comprising a hydrophilic zeolite and a hydrophobic
zeolite.
6. The insert as claimed in claim 5 wherein the hydrophobic zeolite
is an ammonium zeolite and the hydrophilic zeolite is a sodium
aluminosilicate.
7. The insert as claimed in claim 1 wherein the zeolite comprises a
surface area of substantially 400 m.sup.2/g.
8. The insert as claimed in claim 1 further comprising powdered
activated carbon.
9. The insert as claimed in claim 8 wherein a weight % ratio of the
activated carbon to the zeolite as part of the insert is in the
range 0.01:1 to 0.05:1.
10. The insert as claimed in claim 1 wherein the polyacrylate
superabsorbent is granular.
11. The insert as claimed in claim 1 wherein the superabsorbent
comprises sodium or calcium polyacrylate.
12. The insert as claimed in claim 1 further comprising a water
soluble paper formed as a sachet to house the superabsorbent and
the zeolite.
13. The insert as claimed claim 1 further comprising a water
soluble film to house the superabsorbent and the zeolite.
14. The insert as claimed in claim 1 further comprising a gel cap
to house the superabsorbent and the zeolite.
15. The insert as claimed of claim 1 further comprising a plastic
straw or plastic wand to house the superabsorbent and the
zeolite.
16. The insert as claimed in claim 1 wherein the insert is formed
as a soluble tablet.
17. The insert as claimed in claim 1 comprising 1,000 mg to 10,000
mg of polyacrylate superabsorbent.
18. The insert as claimed in claim 1 comprising 25 mg to 5,000 mg
of the powdered zeolite.
19. The insert as claimed in claim 1 comprising a metallic salt
impregnated zeolite.
20. An ostomy bag comprising an insert as claimed in claim 1.
Description
[0001] The present invention relates to a superabsorbent and
malodour control composition and in particular, although not
exclusively, to a superabsorbent for solidifying collected matter
excreted by the body and a control agent for controlling odours
associated with the excreted matter.
[0002] Ostomy patients typically wear an ostomy bag into which body
waste is excreted. Ostomy patients fall into three categories, each
category necessitating the patient wearing an ostomy bag. Firstly,
urostomy patients typically have had their bladders removed.
Accordingly in this case, urine is passed through the stoma and
into the ostomy bag. Secondly, colostomy patients have undergone
surgery to remove all or part of the colon necessitating an ostomy
bag to collect both liquid and solid excreted matter. Thirdly,
ileostomy patients similarly rely upon an ostomy bag to collect
excreted matter which is redirected through the abdominal wall.
[0003] Generally an ostomy bag comprises an opening which is sealed
against the patient's skin around the surgically created body
orifice, termed a stoma. Many ostomy bags are provided with a
discharge outlet to allow excreted matter to be emptied from the
ostomy bag by the patient.
[0004] When body waste is excreted into the ostomy bag it continues
to release malodours which are unpleasant and can cause
embarrassment to the patient. Also, where the excreted matter is in
liquid form, leakage from the ostomy bag is a potential risk which
would also cause embarrassment to the patient.
[0005] A number of additives have been proposed for ostomy bags
designed to solidify excreted fluid matter and reduce unpleasant
malodours. US 2002/0055594 discloses a superabsorbent tablet
configured to thicken body excretions. The tablet comprises a
superabsorbent polymer in the form of cross linked sodium or
calcium polyacrylate designed to provide quick gelling of the
ostomy bag contents following excretion.
[0006] U.S. Pat. No. 6,852,100 also discloses an ostomy pouch
configured to reduce unpleasant odours. Superabsorbent fibres are
used in combination with a malodour counteractant selected from
various different categories of odour controlling (masking and
neutralising) agents including for example hydrogen peroxide and
bacterial growth inhibiters such as sodium nitrate and benzyl
alkonium chloride.
[0007] GB 2329339 discloses a superabsorbent for an ostomy bag
comprising granules of a superabsorbent formed into a stick or rod
and housed within a water soluble outer sleeve. Odour
counteractants, disinfectants and preservatives are also
incorporated within the ostomy bag insert.
[0008] U.S. Pat. No. 5,860,959 discloses a hydroscopic composition
to reduce malodours from an ostomy bag. Water absorbing materials
such as starch or alkaline metal polyacrylates are employed as
superabsorbents in combination with odour counteractants such as
volcanic clays and activated carbon granules.
[0009] However, there exists a need for an ostomy bag insert
configured to effectively solidify or gel excreted matter and
control unwanted malodours.
[0010] The inventors provide a superabsorbent material for
positioning within a stoma bag exhibiting superabsorbent and odour
controlling properties. The superabsorbent blend has been found to
exhibit enhanced malodour reduction over existing ostomy bag
inserts.
[0011] According to a first aspect of the present invention there
is provided an ostomy bag insert comprising: a polyacrylate
superabsorbent; and a powdered zeolite; wherein the superabsorbent
is coated with the powdered zeolite.
[0012] Reference within the specification to zeolite includes
zeolites being microporous and capable of accommodating within
their structure molecular species including ions and in particular
odorous compounds typically found in fecal waste.
[0013] Optionally, the zeolite may comprise a naturally sourced
zeolite mineral including in particular analcime, chabazite,
clinoptilolite, heulandite, natrolite, phillipsite, and
stilbite.
[0014] Optionally, the zeolite is a zeolite blend comprising a
hydrophilic and a hydrophobic zeolite. Alternatively, the zeolite
may be substantially hydrophilic or substantially hydrophobic. A
preferred hydrophobic zeolite comprises an ammonium zeolite being a
zeolite having ammonium groups forming part of the zeolite
structure. A preferred hydrophilic zeolite comprises a sodium
aluminosilicate.
[0015] Optionally, the insert may further comprise powdered
activated carbon. Preferably the insert comprises the zeolite as a
major component and activated carbon as a minor component based on
a dry weight percentage. Optionally, a weight % ratio of the
activated carbon to the zeolite or zeolite blend, as part of the
insert, is in the range 0.01:1 to 0.05:1.
[0016] The powdered zeolite may comprise a particle size equal to
or less than 0.15 mm and/or 0.045 mm and/or 0.075 mm. Optionally,
the zeolite comprises a surface area of substantially 400
m.sup.2/g.
[0017] Preferably, 99% by weight of the zeolite may comprise a
particle size equal to or less than 0.15 mm; 95% by weight of the
zeolite may comprise a particle size equal to or less than 0.075 mm
and 90% by weight of the zeolite may comprise a particle size equal
to or less than 0.045 mm.
[0018] Preferably, the activated carbon comprises and is derived
from coconut shell char. The activated carbon may comprise a
surface area of substantially 1250 m.sup.2/g. Preferably, the
polyacrylate superabsorbent comprises a granular configuration
being at least one or a multiple order of magnitude greater in size
than the particle size of the zeolite or activated carbon.
[0019] Synergistically, the zeolite and optionally the activated
carbon may be bound to the superabsorbent granules by electrostatic
forces. The superabsorbent may comprise sodium or calcium
polyacrylate. Optionally, the zeolite and/or the activated carbon
may comprise any metal impregnated activated charcoal.
[0020] Preferably, the superabsorbent and powdered zeolite or
zeolite blend is housed within a water soluble paper sachet. The
paper sachet may comprise sodium carboxy methyl cellulose and wood
pulp. The edges of the sachet may be heat sealed so as to trap the
granular superabsorbent and zeolite within the envelope formed by
the soluble paper.
[0021] Alternatively, the zeolite or zeolite based blend may be
encased within water soluble films (e.g. PVA films), gel caps,
plastic straws/wands or formed as tablets. Moreover, the insert may
comprise a plurality of separate units (e.g. tablets, gel caps,
sachets). These units would then be inserted separately into the
ostomy bag.
[0022] According to a second aspect of the present invention there
is provided an ostomy bag comprising an insert as described herein.
The insert may be permanently or temporarily attached to an
internal wall of the ostomy bag using conventional means found in
the art. For example, the insert may be attached to the internal
walls via a flap, strap or permeable pouch or cover allowing
release of the superabsorbent and odour absorbing material upon
contact with the excreted body fluid.
[0023] Preferably, the insert comprises 1,000 mg to 10,000 mg of
the polyacrylate superabsorbent and 25 mg to 5,000 mg of the
zeolite or zeolite blend.
[0024] A specific implementation of the invention will now be
described by way of example only, and with reference to the
attached drawings in which:
[0025] FIG. 1 illustrates an ostomy bag comprising an insert
configured to solidify liquid matter within the ostomy bag and
control and reduce malodours according to a specific implementation
of the present invention;
[0026] FIG. 2 illustrates a partial cut-away view of the ostomy bag
insert of FIG. 1 formed as a sachet containing a granular and
powdered material;
[0027] FIG. 3 illustrates a superabsorbent granule coated with a
zeolite material;
[0028] FIG. 4 is a GC chromatogram of solution 1-3 .mu.l/ml
thioacetic acid and 0.5 .mu.l/ml ethanethiol in water;
[0029] FIG. 5 is GC chromatogram of solution 2--aqueous solution
containing superabsorbent polymer;
[0030] FIG. 6 is a GC chromatogram of solution 3--containing
activated carbon;
[0031] FIG. 7 is a GC chromatogram of solution 4--containing
activated carbon and superabsorbent polymer;
[0032] FIG. 8 is a GC chromatogram of solution 5--containing
zeolite blend;
[0033] FIG. 9 is a GC chromatogram of solution 6--containing
zeolite blend and super absorbent polymer;
[0034] FIG. 10 is a GC chromatogram of solution 7--containing
hydrophobic zeolite;
[0035] FIG. 11 is a GC chromatogram of solution 8 containing
hydrophobic zeolite and super absorbent polymer;
[0036] FIG. 12 is a GC chromatogram of solution 9 containing
hydrophilic zeolite;
[0037] FIG. 13 is a GC chromatogram of solution 10 containing
hydrophilic zeolite and superabsorbent polymer;
[0038] FIG. 14 is a GC chromatogram of solution 11 containing CW 90
Zn salt;
[0039] FIG. 15 is a GC chromatogram of solution 12 containing CW 90
Zn salt and superabsorbent polymer;
[0040] FIG. 16 is a graph of the percentage decrease of ethanethiol
and thioacetic acid peaks for solutions 3 to 12;
[0041] FIG. 17 is a graph of the percentage decrease of ethanethiol
peak with increasing absorbent compound concentration; and
[0042] FIG. 18 is a graph of the percentage decrease of thioacetic
acid peak with increasing absorbent compound concentration.
[0043] The inventors provide a material blend configured to
solidify excreted matter within an ostomy bag and to reduce odours
within the ostomy bag which would otherwise be released from the
bag when it is emptied by a patient. A material blend is housed
within a water soluble sachet which provides a convenient means by
which the liquid and odour absorbing material blend may be stored
and transported prior to use within the ostomy bag. The dissolvable
sachet may be used in all manner of pouches or bags designed for
collecting body excretions such as ostomy, drainage bags or other
applications where body fluids require thickening or gelling and
odour control (neutralisation/absorption).
[0044] FIG. 1 illustrates an ostomy bag 100 comprising an internal
chamber 105 and an inlet opening 101 surrounded by an annular
adhesive pad 102. A drainage flap 103 is provided at a lower region
106 of bag 100. An odour controlling and liquid superabsorbent
insert 104 is housed within internal chamber 105 and is dimensioned
so as to pass through inlet opening 101 during initial insertion
prior to attachment of bag 100 and through outlet opening 103 after
empty and reuse of bag 100.
[0045] In use, ostomy bag 100 is secured to the skin of a patient
at the abdominal region, via adhesive pad 102 such that inlet
opening 101 is aligned with the stoma site formed in the patient.
Accordingly, excreted matter passes through the stoma and into
internal chamber 105 of ostomy bag 100 via inlet opening 101.
[0046] The excreted body fluid contacts insert 104 which acts to
gel (partially solidify) the fluid matter and control malodours
within internal chamber 105.
[0047] Following solidification of the excreted matter, the
contents of the ostomy bag 100 may then be emptied via the flap
arrangement 103 configured to dispense liquid and/or solid from
internal chamber 105. Flap 103 may comprise any conventional tap or
flap design configured to allow liquid and/or solid matter to be
released from internal chamber 105. Following emptying of the bag,
a new insert may then be inserted into internal chamber 105 via the
flap 103 such that a user is not required to detach bag 100 from
positioning around the stoma.
[0048] Referring to FIGS. 2 and 3, insert 104 is formed as a sachet
comprising a water soluble paper having an upper layer 200 and a
lower opposed layer 204. The edges of the upper and lower layers
200, 204 are heat sealed 201 to define an internal cavity 202
sealed along all four edges of the rectangular sachet. Insert 104
comprises liquid and odour absorbing material blend 203 (comprising
a polyacrylate based superabsorbent 300 and a powdered zeolite 301)
housed within internal cavity 202 formed by the upper and lower
layers 200, 203. As will be appreciated by those skilled in the
art, the present invention may comprise any specific polyacrylate
comprising superabsorbent properties suitable for use to absorb
fluids, excreted by the human body. The zeolite may comprise any
natural or synthetic zeolite or zeolite composite or blend
configured to control malodours of the type associated with human
body excreted matter. It is preferred that the zeolite is a blend
of a hydrophobic and a hydrophilic zeolite,
[0049] Referring to FIG. 3, it has been found advantageous for
malodour control/reduction to coat the superabsorbent 300 with the
zeolite 301. In particular, the superabsorbent, according to a
specific implementation of the present invention, is formed as
granules or pellets. In this configuration, the finely powdered
zeolite readily coats the external surface of the granules or
pellets providing an active blend exhibiting enhanced odour control
over existing stoma bag inserts. The powdered zeolite may be
maintained at the outer surface of the superabsorbent granules by,
in part, the electrostatic interactions between the superabsorbent
and the powdered zeolite.
[0050] According to one embodiment, the stoma bag insert 104
comprises a sodium polyacrylate superabsorbent 300. The water
soluble sachet comprises sodium carboxy methyl cellulose and wood
pulp comprising a thickness in a range 0.07 mm to 0.09 mm. The
zeolite comprises a zeolite blend having a hydrophilic zeolite
component and a hydrophobic zeolite component. The water soluble
sachet comprises 2 g of sodium polyacrylate and 250 mg of
zeolite.
[0051] According to a further specific embodiment, the insert 104
comprises sodium polyacrylate superabsorbent 300, the same water
soluble sachet as described above, a zeolite blend having a
hydrophilic and a hydrophobic component and powdered activated
carbon.
Experimental Investigation
[0052] The effect of three odour absorbing compounds and a
superabsorbent polymer on the volatilisation of ethanethiol and
thioacetic acid from aqueous solutions have been investigated using
GC headspace techniques.
[0053] It was found that all three of the odour absorbing compounds
and the superabsorbent polymer are effective (to a greater or
lesser degree) at reducing the volatilisation of ethanethiol and
thioacetic acid from aqueous solutions at 37.degree. C.
[0054] The most effective system for reducing the volatilisation of
ethanethiol and thioacetic acid from aqueous solutions at
37.degree. C. was found to be a hydrophilic/hydrophobic zeolite
blend combined with the superabsorbent polymer. This system showed
around a 95% reduction of the ethanethiol peak and 100% reduction
of the thioacetic acid peak.
[0055] Results indicate that at 37.degree. C. and at concentrations
of above 60 mg/5 ml the zeolite blend combined with polymer has
comparable effectiveness with carbon black and polymer at
suppressing the volatilisation of ethanethiol and thioacetic acid
from aqueous solutions.
Analysis
[0056] A GC headspace analysis method was developed during the
course of the investigations and used to quantify the levels of the
odorous thiol compounds, thioacetic acid and ethanethiol, in the
headspace above aqueous samples, with and without the presence of
each of the absorbing compounds. The work found that two
compounds--a zeolite blend and CW90 Zn salt--gave results which
were comparable to activated carbon. Both compounds have the
advantage over carbon black of being opaque/white, which should
enable easier examination of stoma bags containing the
compounds.
[0057] The report below, details further investigations conducted
into the absorption properties of the hydrophobic and hydrophilic
zeolites and the CW90 Zn salt at temperatures more closely
resembling body temperature and in the presence of a superabsorbent
polymer.
Objectives
[0058] To test the capabilities of the zeolites and the CW90 Zn
salt to absorb H.sub.2S, thioacetic acid, ethanethiol and skatole
both in pure aqueous solutions and in the presence of a
superabsorbent polymer.
Method
[0059] A stock solution of the odorous compounds H.sub.2S,
thioacetic acid, ethanethiol and skatole were made up at with 2
mg/ml in water. The samples were analysed using a Perkin Elmer XL40
gas chromatograph with a Zebron ZB-624 capillary GC column (30
m.times.0.32 mm.times.1.8 u) with an FID detector.
[0060] No signals associated with H.sub.2S and skatole were
observed using the method. H.sub.2S was not detected by the FID
detector and skatole was insoluble in water and its low volatility
meant that the concentration in the headspace at 40.degree. C. was
negligible.
[0061] As a result, a second stock solution was prepared with 3
.mu.l/ml thioacetic acid and 0.5 .mu.l/ml ethanethiol in water
only. 5 ml of the stock solution was then added to each of the
following compounds:
TABLE-US-00001 TABLE 1 Summary of the solutions prepared, detailing
the odour absorbing compound employed, its quantity and the
quantity of superabsorbent polymer. Mass of Odour absorbing Mass of
superabsorbent Solution compound compound (mg) polymer (mg) 1 None
0 0 2 None 0 25 3 Activated Carbon 67 0 4 Activated Carbon 62 28 5
Zeolite Blend 62 0 6 Zeolite Blend 59 25 7 Zeolite Hydrophobic 60 0
8 Zeolite Hydrophobic 65 25 9 Zeolite Hydrophilic 60 0 10 Zeolite
Hydrophilic 58 26 11 Cw90 Zn salt 60 0 12 Cw90 Zn salt 60 24
[0062] The GC analysis set up was as follows for all samples:
[0063] Injection port temperature: 140.degree. C.; [0064] Carrier
gas (H.sub.2) pressure 8 psi; [0065] Oven program: [0066]
40.degree. C. isocratic for 5 min; [0067] Ramp to 90.degree. C. at
10.degree. C./min; [0068] isocratic at 90.degree. C. for 2 min;
[0069] FID detector temperature: 240.degree. C.
[0070] Headspace sampling was carried out as follows: [0071]
Equilibrium time 7 minutes with shaking; [0072] Pressurisation 0.5
minutes; [0073] Injection 0.1 minutes; [0074] Withdrawal 0.1
minutes; [0075] Oven temperature 37.degree. C.; [0076] Needle
60.degree. C.; [0077] Transfer line 60.degree. C.
Blank Results (Solutions 1+2)
[0078] Analysis of aqueous solution containing 3 .mu.l/ml
thioacetic acid and 0.5 .mu.l/ml ethanethiol resulted in peaks at
.about.2.5 minutes for ethanethiol and 5.75 minutes for thioacetic
acid, the results are shown in FIG. 4
[0079] The same aqueous solution when added to 25 mg of
superabsorbent polymer showed that the polymer itself had some
odour absorbing qualities without the presence of any odour
absorbing compounds, as shown in FIG. 5. The polymer was more
effective at absorbing thioacetic acid than ethanethiol.
Summary of Results
TABLE-US-00002 [0080] Percentage decrease Percentage decrease of
ethanethiol of thioacetic acid Solution Compounds peak (%) peak (%)
3 Carbon 74 90 4 Carbon + Polymer 91 100 5 Zeolite Blend 89 100 6
Zeolite Blend + 95 100 Polymer 7 Zeolite 32 100 Hydrophilic 8
Zeolite 32 100 Hydrophilic+ 9 Zeolite 80 50 Hydrophobic 10 Zeolite
96 100 Hydrophobic+ 11 Cw90 Zn salt 32 50 12 Cw90 Zn salt + 40 100
Polymer
Effect of Concentration
[0081] The effect of the concentration of the absorbing compounds
and the polymer on the level of odours compound absorption were
also investigated. 5 ml of the stock solution containing
ethanethiol and thioacetic acid was added to vials containing
masses of odour absorbing compounds ranging from .about.20 mg to
.about.150 mg. The results are displayed in the tables below. Note:
all experiments on the absorbing compounds were performed in
aqueous solutions without polymer.
Activated Carbon:
TABLE-US-00003 [0082] Mass of compound Percentage decrease of
Percentage decrease of (mg) ethanethiol peak thioacetic acid peak
27 87 100 39 87 100 63 93 100 103 100 100
Zeolite Blend:
TABLE-US-00004 [0083] Mass of compound Percentage decrease of
Percentage decrease of (mg) ethanethiol peak thioacetic acid peak
22 53 100 40 80 100 59 91 100 101 98 100
Zeolite Hydrophobic:
TABLE-US-00005 [0084] Mass of compound Percentage decrease of
Percentage decrease of (mg) ethanethiol peak thioacetic acid peak
19 53 50 43 77 75 60 83 75 102 95 95
Zeolite Hydrophilic:
TABLE-US-00006 [0085] Mass of compound Percentage decrease of
Percentage decrease of (mg) ethanethiol peak thioacetic acid peak
19 7 100 40 20 100 60 20 100 100 20 100
Cw 90Zn Salt:
TABLE-US-00007 [0086] Mass of compound Percentage decrease of
Percentage decrease of (mg) ethanethiol peak thioacetic acid peak
26 0 50 50 20 50 76 73 90 112 89 95
Superabsorbent Gel:
TABLE-US-00008 [0087] Mass of compound Percentage decrease of
Percentage decrease of (mg) ethanethiol peak thioacetic acid peak
32 13 100 55 27 100 80 40 100 150 33 100
[0088] The performance of the absorbing compounds identified as
solutions 3 to 12 are detailed in FIGS. 6 to 15 respectively.
[0089] A summary of the percentage decrease of the ethanethiol and
thioacetic acid peaks for solutions 1 to 12, based on the gas
chromatography results of FIGS. 4 to 15 are shown in FIG. 16. The
effect of the percentage decrease of the ethanthiol peak with
increasing absorbent compound concentration is illustrated in FIG.
17 and the percentage decrease of thioacetic acid peak with
increasing absorbent compound concentration is shown in FIG.
18.
CONCLUSIONS
[0090] No signals associated with H.sub.2S or skatole were observed
using the GC headspace method. H.sub.2S was not detected by the FID
detector and skatole was insoluble in water and its low volatility
meant that the concentration in the headspace at 40.degree. C. was
negligible.
[0091] All the odour absorbing compounds reduced the peak height of
ethanethiol and thioacetic acid compared to the blank, solution 1.
The polymer also reduced the peak heights of ethanethiol by 20% and
thioacetic acid by 90%.
[0092] Almost all the odour absorbing compounds showed enhanced
peak reduction of ethanethiol and thioacetic acid with the presence
of the superabsorbent polymer, the hydrophilic zeolite was the only
compound which showed little to no enhancement of ethanethiol
absorption by addition of polymer.
[0093] The present results indicate that the hydrophobic zeolite is
more effective at reducing the ethanethiol peak than the thioacetic
acid peak, whilst the hydrophilic zeolite shows the opposite effect
and is much less effective at reducing ethanethiol, but effective
at reducing the thioacetic acid peak.
[0094] The Zeolite blend containing both hydrophilic and
hydrophobic forms (solution 5) absorbed more ethanethiol and
thioacetic acid than the individual zeolites themselves.
[0095] The Zeolite blend (solution 6) combined with the
superabsorbent polymer appears to be the most effective system for
reducing the volatilisation of ethanethiol and thioacetic acid from
aqueous solutions at 37.degree. C. The solution showed .about.95%
reduction of the ethanethiol peak and 100% reduction of the
thioacetic acid peak. The blend was successful because the
hydrophobic zeolite had a greater effect on the absorption of
ethanethiol and the hydrophilic zeolite a greater effect on the
absorption of thioacetic acid.
[0096] At .about.37.degree. C. the performances of the zeolite
blend and activated carbon appear to be roughly comparable.
Activated carbon is more effective at the lower concentrations
(.about.20 mg in 5 ml) at reducing the volatilisation of
ethanethiol and thioacetic acid, but at higher concentrations
(.about.60-100 mg) the zeolite blend performs equally as well.
[0097] Cw 90 Zn salt was the least effective of the three compounds
tested and showed only minor reductions on the levels of
ethanethiol. Reductions in the thioacetic acid peak height were
observed. At higher concentrations, in aqueous solutions, the Cw 90
Zn salt performs relatively well suppressing both the ethanethiol
and thioacetic acid peaks. However, in the presence of the polymer
it performed less well, possibly indicating an inhibiting effect of
the polymer on the salt's performance.
[0098] Generally, increasing the concentration of the odour
absorbing compound decreased the volatilisation of ethanethiol and
thioacetic acid. The exception was the hydrophilic zeolite, which
reached a plateau of ethanethiol reduction at .about.20%.
* * * * *