ZA200609182B - Selective filtration of cigarette smoke using chitosan derivatives - Google Patents

Description

UNITED STATES NON-PROVT SIONAL

UTILITY PATENT APPLICATION

For

SELECTIVE FILTRATION OF CIGARETTE SMOKE

USING CHITOSAN DERIVATIVES by

JOHN W.CARAWAY, JR, a United States Citizen, residing at 320 Castlegate Rd., Macon,

Georg iaUSA. 31210

Attorney Docket No. BW-446-1(R—03-02)

CROSS-REFERENCE TO RELATED APPLICATIONS

This international patent application is a Paris Convertion filing and claims priority to and be=nefit from U.S. Patent Application Serial Number 10/842,165, filed on May 10, 2004, curren_tly pending.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR

DEVELOPMENT

Not applicable.

FIELD OF INVENTION

This invention concerns improvements relating to tobacco smoke filters. More particularly, the invention relates to a cigarette filter that can selectively remove undesirable constituents from tobacco smoke.

BACKGROUND OF THE INVENTION

A wide variety of materials have been suggested in the prior art as filters for tobacco smoke. Examples of such filter materials include cotton, paper, cellulose acetate, and certain synthetics. Many of these filter materials, however, are only effective in the removal of particulates, tars and condensable components from tobacco smoke. The art is replete with a myriad of filtration techniques and materials for removing undesirable components in smoke and for causing other reactions as the smoke passes through filtration beds or other reactive media. Among the problems encountered with prior filters has been the plugging or clogging with use and the consumption or rendering ineffective of reactive filtering surfaces and materials.

Filters made from filamentary or fibrous material such as cellulose acetate tow or paper are somewhat effective in the rermoval of particulate phase constituents of tobacco smoke. However, they have little or no effect in removing certain gaseous components in the vapor phase of the tobacco smoke such as hydrogen cyanide, aldehydes, carbonyls, metals and sulphides. These volatile constituents can be removed by adsorption and absorption on a suitable surface or by chemical reaction.

Some known substances which act as absorbents and adsorbents include activated carbon, porous minerals, and ion exchange resins. Ion-exchange resins of porous structure have been found to be somewhat effective, but their efficiency diminishes during smoking, as does that of carbon and porous minerals. This may be due to the material becoming saturated and, therefore, increasingly inactive or it may be due to the release of adsorbed material by thermal desorption of retained substances.

Resins which contain major proportions of tertiary amino or quaternary ammonium groups have been found not to be suitable for removing aldehydes from tobacco smoke.

Chitosan and chitosan with a maximum number of amino groups have been found not to be effective. Among the problems encountered with these materials is that they do not provide a filtration media allowing for the continuous flow of smoke at a low pressure differential or gradient. Other problems with selective filtration medias lmave been found. For example, the use of certain amino acids, such as glycine, have been fourad effective in removing aldehydes in tobacco smoke. However, it has been discovered that w hile glycine can reduce the level of formaldehyde in tobacco smoke, it is not stable in the cigarette filter manufacturing process.

Moreover, the use of amino acids causes the release of amrmonia odor during storage.

SUMMARY OF THE INVENTION

It has been discovered that chitosan can be chemically modified to have the physical attributes of a filter medium and have a chemical composition capable of effectively adsorbing and absorbing undesirable smoke ingredients, yi elding superior performance as a cigarette filter.

Thus, it is an object of the present invention to prowide cigarette filter arrangements and, more particularly, cigarette filters that can selectively remove undesirable constituents in the vapor phase of tobacco smoke such as hydrogen cyanide, aldehydes, metals and sulphides without the drawbacks or disadvantages associated with the prior art as previously described.

A further object is to provide a novel cigarette and smoke filter embodying a porous resin of cross-linked chitosan.

An additional object is to provide cross-linked chitosan reactive materials having a high ratio of surface-to-volume and having a reduced number of reactive amino groups for selective smoke filtration in a smoking article.

According to the present invention, a tobacco-smolee filter includes an adsorbent / absorbent for removal of undesirable volatile tobacco-smolke constituents such as hydrogen cyanide, aldehydes, carbonyls, metals and sulphides. Specifically, the instant invention is direc ted to particularly efficient tobacco smoke filtration compoun ds of chitosan cross-linked with glutaraldehyde and chitosan cross-linked with glyoxal.

Chitosan is cross-linked with glutaraldehyde and glyoxal to form porous resins having ahigh surface area to mass ratio for the selective filtration of cigar-ette smoke, particularly for the removal of undesirable smoke constituents such as aldehydes, bhydrogen cyanide, carbonyls, sulphides and metals.

Chitosan is a linear polyglucosamine polymer obtained frorn the deacetylation of chitin, a polysaccharide found in the exoskeleton of crustaceans. Chitin also occurs in insects and im lesser quantities in many other animal and vegetable organisms. Chitin is a linear polyrmer of 2-deoxy, 2-acetyl-amino glucose analogous to cellulose in chemical structure. It is ins oluble in almost all media except strong mineral acids and due to the acetylated amino group is relatively unreactive.

When chitin is deacetylated by treatment with strong alkalizs, the product is chitosan which contains one free amino group for each glucose building unit in the polymer. It is still a long chain linear polymer but is now a highly reactive cationic poly-electrolyte material. It will Form salts with simple organic acids, such as formic, acetic, taxtaric, citric, etc. and is solubsle in dilute aqueous solutions of such substances. Chitosan is: nontoxic and biode=gradable, and it has found utility in numerous applications, imcluding chromatography, drug delivery, and cosmetics.

A porous chitosan resin may be formed by a phase inversion technique. This is accormplished by dissolving flaked or powdered chitosan in a suita®le solvent, such as aqueous acid, and then coacervating in a solution of aqueous base t-o form water swollen chitosan gel beads. The beads may be cross-linked using glutaraldehyde, and separately with glyoxal, to improve the mechanical strength and reduce the solubility of the toeads. The wet beads are then freeze dried to yield a porous cross-linked resin. Drying may also be accomplished by vacuum or air drying.

A porous resin may also be prepared using a thermally induced phase= separation techniques. This is accomplished by dissolving flaked or powdered chitosan in a suitable solvent, s-uch as aqueous acetic acid, and then adding the solution to a non-somlvent, such as methanol , and cooling the resulting solution below the freezing point of the chitosan solution which yields frozen beads. These beads may then be neutralized with a base and cross-linked with glutaraldehyde and separately with glyoxal to modify the final propertie=s of the chitosan resin. The resulting beads may then be freeze dried to yield a porous cross-li_nked chitosan resin. Drying may also be accomplished by vacuum and by air drying.

The cross-linked resins produced by both methods have a reduced number of reactive amino groups. The reduced number of reactive amino groups is a result of thee cross-linking reaction with glutaraldehyde or glyoxal. It has been surprisingly discovered that the described invention, having a reduced number of reactive amino groups, is selective in removing hydrogen cyanide and formaldehyde from tobacco smoke. It has a_lso been surprisingly found that the cross-linked chitosan resin having a reduced number of reactive amino groups exhibits greater selective removal activity than that associated with the prior art where a maximum number of reactive amino groups have been employed.

Thhe porous resin of the present invention may be incorporated into a «cigarette in a variety of ways. The resin may be disposed between filter sections wherein these sections may be comprised of fibrous, filamentary and paper materials. The resin ma_y also be dispersed throughout a filter tow. Alternatively, the resin may be placed within a filter bed in a filter se ction and the resin may be packed along the filter bed. The resin m.ay also be incorporated into a part of the cigarette filter such as the tipping paper, a shaped paper insert, a plug, a space, or even a free-flow sleeve. Additionally, the resin may be incorporated into cigarette filter pape r, attached to the tobacco rod with tipping paper or even incorporated within a cavity in the filter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Examples of the present invention are given below by way of illustration and not by way of limitation. "These examples include two distinct methods of preparing chitoszan beads as well as several d distinct methods of cross-linking the chitosan beads. All of the fol lowing examples yield porous cross-linked chitosan resin beads having a reduced number of reactive amino groups.

EXAMPLES

EXAMPLE I:

Porous chitosan resin was synthesized according to a phase inversion techniq ue. This was accomplished by preparing a 7% chitosan solution by dissolving approximately 20 grams of chitosan flakes (gporactical grade) in 3.5% acetic acid. The mixture increased in vis cosity and gelled upon thes completion of the chitosan addition. Further dilution with acetics acid resulted in a solutioen having approximately 3% chitosan flake. This provided for a chitosan solution having a mmore manageable viscosity. The total amount of acetic acid used tao dissolve the chitosan flake was approximately 665 milliliters. The solution was then filtered to separate any und issolved materials. This chitosan solution was then added dropw lise to a precipitation bath o f 2 molar sodium hydroxide to yield water swollen gel beads. Th e gel beads were then filtered and washed with deionized water until neutral, pH of the wa. sh water being approximatel y 7.

Heterogeneous cross-Rinking of the chitosan beads was then accomplished by suspending the beads for several hours in approximately 1 liter of 2.5% aqueous solution of glutaraldehyde. After cross-linking, the beads were then filtered and washed with warm deionized water to remove any excess glutaraldehyde. Subsequently, the beads were freeze dried which resulted in porou s glutaraldehyde cross-linked chitosan resin beads. The BET surface area of the resin was mmeasured to be approximately 120 m%g. The beads were then milled and sieved to retain particles having approximately 16 to 70 mesh. A surface area analysis of the milled resin showed no appreciable change in surface area. The BET surface area of the sieved sample was measured to be approximately 117 m%/g.

EXAMPLEIL:

Porous chitosan resin was synthesized according to the phase inversion technique in

Example 1. In this example the heterogeneous cross-linking of the chitosan beads was accomplished by suspending the beads for several hours in a 2.5% aqueous solution of glyoxal. After cross-linking, the beads were filtered and washed with warm deionized water to remove any excess glyoxal. The beads were then freeze dried which resulted in porous glyoxal cross-linked chitosan resin beads.

EXAMPLE IIL:

Porous chitosan resin was prepared according to a thermally induced phase separation procedure. A 4% chitosan so lution was prepared by dissolution of chitosan powder (Vansen

Chemical; 92% deacetylation) in 3.5% acetic acid. A precipitation bath of sodium hydroxide (2 molar) in 20:80 methanol / water solution was prepared and cooled to 0 °C. The chitosan solution was then added dropwise to the precipitation bath with moderate stirring.

Precipitation of chitosan occurred shortly after addition of the solution to the precipitation bath. The precipitation bath having the chitosan precipitate was then allowed to return to room temperature. The resulting beads were filtered and washed with deionized water until the wash water became neutral, having a pH of approximately 7.

Heterogeneous cross-linking of the chitosan beads was then accomplished by suspending approximately 396 grames of wet beads in approximately 1980 milliliters of 2.5% aqueous glutaraldehyde solution for several hours. After cross-linking, the beads were filtered and washed with both warm and cold deionized water to remove any excess glutaraldehyde. Subsequent freeze drying of the beads resulted in porous glutaraldehyde cross-linked chitosan resin beads. T he beads were then milled and sieved to approximately 16 to 70 mesh. The BET surface area of the resin was measured to be approximately 210 m2/g.

EXAMPLE IV:

Porous chitosan resin was prepared according to the thermally induced phase separation procedure in Example III. In this example, the heterogeneous cross-linking of the chitosan beads was accomplished by suspending approximately 261 grams of wet beads in approximately 1300 milliliters of 2.5% aqueous glyoxal solution for several hours. After cross-linking, the beads were filtered and washed with both warm and cold deionized water to remove any excess glyoxal. Subsequent freeze drying resulted in porous glyoxal cross- linked chitosan resin beads. The beads were then milled and sieved to approximately 16 to 70 mesh. The BET surface area of the cross-linked resin was measured to be approximately 145 m 2/g.

EXAMPLE V:

Porous chitosan resin was prepared accordimg to the thermally induced phase separation procedure in Example III. In this example, the heterogeneous cross-linking of the chitosan beads was accomplished by suspending the beads in a solution of glutaraldehyde and ethanol for several hours. After cross-linking, the b eads were filtered and washed with ethanol to remove any excess glutaraldehyde. Subsequent vacuum drying resulted in porous glutaraldehyde cross-linked chitosan resin beads.

EXAMPLE VI:

Porous chitosan resin was prepared accordirag to the thermally induced phase separation procedure in Example III. In this examp le, the heterogeneous cross-linking of the chitosan beads was accomplished by suspending the beads in a solution of glutaraldehyde and water for several hours. After cross-linking, the beads were filtered and washed with ethanol to remove any excess glutaraldehyde. Subsequent wacuum drying resulted in porous glutaraldehyde cross-linked chitosan resin beads.

Even though these examples specify amounts or concentrations of materials used in making several embodiments of the present invention, a wide range of concentrations and amounts of materials may be used to practice the present invention. For example, the crosslinker solution may be in a range of concentration of about 0.1% to about 50%, the : chitosan solution may be in a range of concentratiom of about 0.1% to about 20%, the acetic acid solution may be in a range of about 0.1% to ab-out 10%, and the base solution may be in arange of about 1 to about 5 molar sodium hydroxi de. Additionally, the range of hours for cross-linking reaction may be from about 1 hour to up to about 24 hours.

EXAMPLES O-F USE

A cigarette typically contains two sections, a tebacco-containing portion sometimes referred to as the tobacco or cigarette rod, and a filter portion which may be referred to as the filter tipping. A cigarette sample with a cavity filter w-as prepared by removing the existing filter on a cigarette made by standard production techniques, and replacing with a filter tipping having a cellulose acetate section at the tobacco end of the filter and a cellulose acetate section at the mouth end of the filter leaving a middle cavity. Sample sets of semolina (an inert filler material), chitosan resin synthesized by- phase inversion technique and cross- linked with glutaraldehyde (Ex. I), chitosan resin synthesized by the thermally induced phase separation procedure and cross-linked with glutaraldehyde (Ex. III), chitosan resin synthesized by the thermally induced phase separatior procedure and cross-linked with glyoxal (Ex. IV), chitosan resin synthesized by the thesrmally induced phase separation : procedure and cross-linked with glutaraldehyde in eth anol, washed with ethanol, and vacuum: dried (Ex. V), and chitosan resin synthesized by the thmermally induced phase separation procedure and cross-linked with glutaraldehyde in water, washed with ethanol, and vacuum dried (Ex. VI), were prepared using a 50 mg sample load in the middle cavity of the filter tipping. This loading was consistent for each sample “to provide comparable results. Resin loading in a filter of the present invention may be in a range of about 10 mg to about 200 mg.

Each sample was pressure drop selected to minimize ssmoke delivery variances.

Several tests were conducted to determine the ability of the cigarette filter of the present invention to remove undesirable constituents Erom tobacco smoke as compared to conventional devices. The tests measured the amount: of undesirable constituents removed from the mainstream smoke after the cigarette was ful. ly smoked. The following data sets illustrate the performance achieved in the filtration of ~ volatile constituents of tobacco smoke for each of the preferred embodiments as compared taw the control material, semolina.

Analytical results are reported on the vapor phase and whole smoke analyses as indicated in the following tables. Percent reduction refers to the difference, in %m, between the amount of the analyte measured in the vapor phase or whole mainstream smok_e of cigarettes having filter tipping containing semolina and chitosan resin.

Vapor Phase Smoke Analysis for Chitosan Resin Prepared by Phase= Inversion Technique [Ex. I]

Percent Reduction (%)

Analyte Chitosan cross-linked with glutaraldehyde :

Ex. 1

Hydrogen Cyanide 49

Acetaldehyde 10

Acetonitrile 11

Acrolein 15

Propionaldehyde 11

Acetone 7

Methy! Ethyl Ketone + Butyraldehyde 16

Crotonaldehyde 13

Whole Smoke Hydrogen Cyanide Analysis for Chitosan Resin Prepeared by Phase Inversion

Technique [Ex. I]

Percent Reduction (%)

Analyte Chitosan cross-linked with glutaraldehyde

Hydrogen Cyanide 41

Whole Smoke Carbonyl Analysis for Chitosan Resin Prepared by P hase Inversion Technique [Ex. I

Percen_t Reduction (%)

Chitosan cross-1anked with glutaraldehyde

Ex. I

Formaldehyde 36

Acetaldehyde 13

Acetone 5

Acrolein 11

Propionaldehyde 16

Crotonaldehyde 9

Butyraldehyde 17

Vapor Phase Smoke Analysis for Chitosan Resin Prepared by Therrmally Induced Phase

Separation [Exs. [1I-IV

Percent Reduction (*2%)

Chitosan cross-linked with Chitosan cross-linked with glutaraldehyde glyoxal

Ex. 1II Ex IV

Acextaldehyde 13 31

Acetone 21 30

Acetonitrile 18 26

Acrolein 29 36

Acmrylonitrile 21 29

Crotonaldehyde 7 42

Hydrogen cyanide 60 45

Me=thyl ethyl ketene 21 29

Prospionaldehyde 23 36 i-B-utyraldehyde 27 35 n-BButyraldehyde 27 40

Whaole Smoke Hydrogen Cyanide Analysis for Chitosan Resin Pre pared by Thermally

Ind uced Phase Separation [Exs. I1I-1V] } Percent Reduction (2-6)

Chitosan cross-linked with Chitosan cross-linked with glutaraldehyde glyoxal

Ex. III ExIV

Hydrogen cyanide 54 29

Whaole Smoke Carbony! Analysis for Chitosan Resin Prepared by “Thermally Induced Phase

Separation [Exs. III-IV]

Percent Reduction €%)

Chitosan cross-linked with Chaitosan cross-linked with glutaraldehyde glyoxal

Ex. HI ExIV

Acetaldehyde 1 2

Acetone 5 0

Acrolein 10 3

But-yraldehyde 14 8

Crotonaldehyde 20 9

Formaldehyde 50 46

Pro pionaldehyde 17 19

Wh ole Smoke Trace Metals Analysis for Chitosan Resin Prepared by Thermally Induced

Phamse Separation [Exs. [I-IV]

Percent Reduction (%)

Chitosan cross-linked with Chitosan cross-linked with glutaraldehyde glyoxal

Ex. ITI Ex IV

Cadmium 32 38

Vapor Phase Smoke Analysis for Chitosan Resin Prepared by Thermally Induced Phasse

Separation [Ex. V]

Percent Reduction (%)

Chitosan cross-linked with glutaraldehyde

Ex. V

Acetaldehyde 9

Acetone 6

Acetonitrile 3

Acrolein 13

Crotonaldehy/de 7

Hydrogen Cyanide 36

Methyl Ethyl Ketone 6

Propionaldehryde 11 i-Butyraldehyde 9 n-Butyraldehiyde 10 .

Whole Smoke Hydrogen Cyanide Analysis for Chitosan Resin Prepared by Thermally

Induced Phase Separation [Ex. V]

Percent Reduction (%)

Chitosan cross-linked with glutaraldehyde

Ex. V

Hydrogen Cyanide 27

Whole Smoke Carbonyl Analysis for Chitosan Resin Prepared by Thermally Induced WPhase

Separation [Ex. V]

Percent Reduction (%)

Chitosan cross-linked with glutaraldehyde

Ex. V

Acetonitrile 3

Acetaldehyde 27

Acetone 24

Acrolein 32

Butyraldehyde 41

Crotonaldehyde 30

Formaldehyde 58

Propionaidehyde 33

Whole Smoke Trace Metals Analysis for Chitosan Resin Prepared by Thermally Induced

Phase Separation [Ex. V]

Percent Reduction (%)

Chitosan cross-linked with glutaraldehyde

Ex. V

Cadmium 38

Vapor Phase Smoke Ma nalysis for Chitosan Resin Prepared by Thermally Induced Phase

Separation [Ex. VI]

Percent Reduction (%)

Chitosan cross-linked with glutaraldehyde

Ex. VI

Acetaldehyde 3

Acetone 4

Acrolein 9

Crotonaldehyde 11

Hydrogen Cyanide 30

Methyl Ethyl Ketone: 11

Propionaldehyde 6 i-Butyraldehyde 7 n-Butyraldehyde 11

Whole Smoke Hydrogzen Cyanide Analysis for Chitosan Resin Prepared by Thermally

Induced Phase Separation [Ex. VI]

Percent Reduction (%)

Chitosan cross-linked with glutaraldehyde

Ex. VI

Hydrogen Cyanide 30

Whole Smoke Carbormyl Analysis for Chitosan Resin Prepared by Thermally Induced Phase

Separation [Ex. VI]

Percent Reduction (%)

Chitosan cross-linked with glutaraldehyde

Ex. VI

Acetaldehyde 0

Acetone 0

Acrolein 0

Butanone 1

Butyraldehyde 14

Crotonaldehyde 36

Formaldehyde 37

Propionaldehyde 0

Whole Smoke Trace Metals Analysis for Chitosan Resin Prepared by Thermally Induced

Phase Separation [Ex. VI]

Percent Reduction (%)

Chitosan cross-linked with glutaraldehyde

Ex. VI

Cadmium 26

The data surprisingly showed the cross-linked chitosan resin described in this invention is selective in removing aldehydes and hydrogen cyanide in cigarette smoke compared to the inert semolina comtrol. The glutaraldehyde cross-linked chitosan resin reduced the vapor phase delivery of hydrogen cyanide by 60% versus a control sample (Ex.

HI). In a separate test, non-crosslEnked ground chitosan particles showed no effect on the vapor phase hydrogen cyanide deLivery. The glutaraldehyde cross-linked chitosan resin also decreased whole smoke hydrogen cyanide delivery by 54%, and mainstream whole smoke formaldehyde delivery was decreased by 50% compared to the control sample (Ex. HI).

While the invention has besen described with reference to preferred embodiments, it is to be understood that variations ard modifications may be resorted to as will be apparent to those skilled in the art. Such varia tions and modifications are to be considered within the purview and scope of the inventio-n as defined by the claims appended hereto.

Claims (1)

1. : CELIAC "R ) Replacement Sheets We clairm: Claim 1. A tobacco-smoke filter comprising a chitosan resin haz ving chitosan cross-linked with a comnstituent selected from the group consisting of glutaraldelmyde and glyoxal, said ~ cross-linfked chitosan resin having a BET surface area of at least 5 lg.

   Claim 2. A filter according to Claim 1, wherein said resin is cross-linked with glutaraldeehyde, Claim 3. A filter according to Claim 1, wherein said resin is cromss-linked with glyoxal.

   Claim 4. A filter according to Claim 1, wherein said resin is in gparticulate form within a size ranges of approximately 17 mesh to approximately 70 mesh.

   Claim §. A cigarette filter according to Claim 1, wherein said re=sin comprises milled particles.

   Claim 6. A filter according to Claim 1, wherein said tobacco smoke filter has said resin : present irr. a range from about 10 mg to about 200 mg.

   Claim 7. A filter according to Claim 1, wherein said resin is in particulate form and is disposed between filter sections, said filter sections having materials selected from the group consisting of fibrous, filamentary, paper, and combinations thereof.

   Claim 8. A filter according to Claim 1, wherein said resin is in p-articulate form and is ¥ dispersed dna filter tow.

   Claim 9. A method of smoke filtration comprising providing a srnoking article filter having cht tosan resin cross-linked with a constituent selected from tExe group consisting of glutaraldehyde and glyoxal, and passing smoke through said filter, saaid cross-linked chitosan resin havirag a BET surface area of at least 5 m2/g.

   I —— REE ) Replacement Sheets . Claim 10. A mmethod of fluid-flow filtration that comprises providing a fit tration bed having cross-limked chitosan resin in said bed and passing fluid containing constituents through said filtration bed, said cross-linked chitosan resin having a BET su face area of at least S m2/g. : Claim 11. A mmethod as claimed in Claim 10 and in which the providing s tep comprises packing said chitosan resin within said bed.

   Claim 12. A rmethod as claimed in Claim 10 in which said resin is in a pasrticulate form having a size of about 16 mesh.

   Claim 13. A method as claimed in Claim 10 and in which said providing =step further comprises packing said cross-linked chitosan resin along said bed.

   Claim 14. A rmethod as claimed in Claim 10 wherein said fluid is cigarettes smoke and said constituents comraprises pyrolysis products of cigarette materials.

   Claim 15. A mnethod of removing from cigarette smoke pyrolysis productss of cigarette materials comprising providing a filtration region having cross-linked chitosaan resin disposed throughout the region and passing said pyrolysis products through said filtrat-ion region, said cross-linked chit«osan resin having a BET surface area of at least § m2/g.

   Claim 16. A tobacco smoke filtration media obtained by the steps of: dissolving chitos an in a first solution having acetic acid in a range of about 0 .1% to about ol 10% forming a second solution having chitosan in a range of about 0.1% to about 20%; filtering said second solution; adding said secorad solution drop-wise to a precipitation bath, wherein said precipitation bath has sodium hydroxide in a range of about 1 malar to about 5 molar, forming ggel beads; rinsing said gel beeads; 17 : = mmm eo FERRI

   ) Replacement Sheets suspending said gel beads na cross-linking solution for about 1 hour to about 24 hou xs’ forming cross-linked beadss, wherein said cross-linking solution has approximately 0. 1% to approximately 50% of a cross-linking compound selected from the group consisting osf glutaraldehyde and glyoxal rinsing said cross-linked bezads; and } | drying said cross-linked beads forming a porous chitosan crossed-linked resin bead.

   Claim 17. The smoke fil®ration media of Claim 16 wherein said cross-linking compeound is glutaraldehyde.

   Claim 18. The smoke filtration media of Claim 16 wherein said cross-linking compeound is glyoxal.

   Claim 19. A tobacco smoke filtration media obtained by the steps of: dissolving chitosan in an ac etic acid solution having acetic acid in a range of about 0.1% to about 10% forming a chitosan solution having approximately 0.1% to approximately 20% chitosan; cooling a precipitation bath below ambient room temperature, wherein said precipitatieon bath has sodium hydroxide, wate=r, and methanol; adding said chitosan solution drop-wise to said precipitation bath forming gel beads; warming said precipitation bath having said gel beads to about ambient room temperature; rinsing said gel beads; suspending said gel beads foar about 1 hour to about 24 hours in a cross-linking solutiora : having approximately 0.1% to approximately 50% of a cross-linking compound selected from the group consisting of glutaraldehyde and glyoxal forming cross-linked beads; rinsing said cross-linked bea ds; and 18 ] mm ma Lo /i

   E SSE Replacement Sheets drying said cross-linked beads forming a porous chitosan crossed-linked resin bead. Claim 20. The smoke filtration media of Claim 19 wherein said cross-linking compound is glutaraldehyde. Claim 21. The smoke filtration media of Claim 19 wherein said cross-linking compound is - glyoxal. Claim 22. A tobacco-smoke filter comprising in the range of about 10 mg to about 200 mg of a cross-linked chitosan resin, said resin having a size within the range of about 16 mesh to about 70 mesh, said resin having a BET surface area of at least 5 m2/g.

   E .Claim 23 The cigarette filter according to Claim 22, wherein said filter is attached to a tobacco rod by tipping paper. Claim 24. The cigarette filter according to Claim 22, wherein said resin is incorporated in : : one or more cigarette filter parts selected from the group consisting of tipping paper, shaped paper insert, a plug, a space, and a free-flow sleeve. } Claim 25. The cigarette filter according to Claim 22, wherein said resin is incorporated in cigarette filter paper. Claim 26. A method of manufac turing a filter which is useful for removing a gaseous component of a gas mixture, comprising steps of: preparing a filter media having a cross-linking compound selected from the group consisting . of glutaraldehyde and glyoxal, wherein said cross-linking compound is cross-linked to chitosan forming a bead having a BET surface area of at least 5 m/g; and incorporating said filter media in a filter wherein said filter media removes said gaseous component of said gas mixture, Claim 27. The method according to Claim 26, further comprising attaching said filter to a 19 [ ee me me FREER

   : ’ °l W— EEEASORRENE ERTRNNG Replacement Sheets tobacco rod -with tipping paper.

   Claim 28. The method according to Claim 26, wherein said filter media is ®ncorporated in : one or more cigarette filter parts selected from the group consisting of tipping paper, shaped paper insert, a plug, a space, and a free-flow sleeve. : : : Claim 29. The method according to Claim 26, wherein said cross-linking ceompound is glutaraldehyde. : Claim 30. The method according to Claim 26, wherein said cross-linking ceompound is glyoxal. : Claim 31. The method according to Claim 26, wherein said cross-linking ceompound is incorporated in a cavity of said filter.

   Claim 32. A method of removing a gaseous component of a gas mixture co-mprising passing said gras mixture in contact with a filter, wherein said filter has a reage=nt consisting : | essentially of at least one reactive functional group cross-linked to chitosan forming a bead having a BE'E surface area of at least 5 m%/g such that said reagent adsorbs, ab:sorbs, or chemically re=acts with said gaseous component of said gas mixture and remov—es said gaseous component from said gas mixture, wherein said functional group is selected freom the group consisting of glutaraldehyde and glyoxal. : Claim 33. "The method according to claim 32, further comprising steps of ge=nerating said gas mixture and directing a gas stream containing said gas mixture through sai=d filter such that said comgponent of said gas mixture to be removed is adsorbed, absorbed, sor chemically reacted with s aid reagent and prevented from reentering said gas stream.

   Claim 34. A tobacco-smoke filter comprising cross-linked chitosan resin beads, said cross- linked chitosan resin beads having a reduced number of reactive amino groups than said

   } = mm mime [i]

   ~ (v RE i —— ed ’ Replacement Sheets , it in beads priox to cross-linking. ov Tame chitosan resin p g 97 oy