Selective filtration of cigarette smoke using chitosan derivatives

Abstract

A smoking article filter having a porous resin with a high surface area to mass ratio comprised of a chitosan derivative. Preferred embodiments include chitosan cross-linked with glutaraldehyde and chitosan cross-linked with glyoxal. The chitosan derivative provides for the selective filtration of cigarette smoke, particularly for the removal of aldehydes, hydrogen cyanide, heavy metals and carbonyls.

1 . A tobacco-smoke filter comprising a chitosan resin having chitosan cross-linked with a constituent selected from the group consisting of glutaraldehyde and glyoxal.  
     
     
         2 . A filter according to  claim 1 , wherein said resin is cross-linked with glutaraldehyde.  
     
     
         3 . A filter according to  claim 1 , wherein said resin is cross-linked with glyoxal.  
     
     
         4 . A filter according to  claim 1 , wherein said resin is in particulate form within a size range of approximately 17 mesh to approximately 70 mesh.  
     
     
         5 . A cigarette filter according to  claim 1 , wherein said resin comprises milled particles.  
     
     
         6 . A filter according to  claim 1 , wherein said tobacco smoke filter has said resin present in a range from about 10 mg to about 200 mg.  
     
     
         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.  
     
     
         8 . A filter according to  claim 1 , wherein said resin is in particulate form and is dispersed in a filter tow.  
     
     
         9 . A method of smoke filtration comprising providing a smoking article filter having chitosan resin cross-linked with a constituent selected from the group consisting of glutaraldehyde and glyoxal, and passing smoke through said filter.  
     
     
         10 . A method of fluid-flow filtration that comprises providing a filtration bed having cross-linked chitosan resin in said bed and passing fluid containing constituents reactive with said resin through said filtration bed.  
     
     
         11 . A method as claimed in  claim 10  and in which the providing step comprises packing said chitosan resin within said bed.  
     
     
         12 . A method as claimed in  claim 10  in which said resin is in a particulate form having a size of about 16 mesh.  
     
     
         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.  
     
     
         14 . A method as claimed in  claim 10  wherein said fluid is cigarette smoke and said constituents comprises pyrolysis products of cigarette materials.  
     
     
         15 . A method of removing from cigarette smoke pyrolysis products of cigarette materials comprising providing a filtration region having cross-linked chitosan resin disposed throughout the region and passing said pyrolysis products through said filtration region.  
     
     
         16 . A tobacco smoke filtration media obtained by the steps of: 
 dissolving chitosan in a first solution having acetic acid in a range of about 0.1% to about 10% forming a second solution having chitosan in a range of about 0.1% to about 20%;    filtering said second solution;    adding said second solution drop-wise to a precipitation bath, wherein said precipitation bath has sodium hydroxide in a range of about 1 molar to about 5 molar, forming gel beads;    rinsing said gel beads;    suspending said gel beads in a cross-linking solution for about 1 hour to about 24 hours forming cross-linked beads, wherein said cross-linking solution has approximately 0.1% to approximately 50% of a cross-linking compound selected from the group consisting of glutaraldehyde and glyoxal;    rinsing said cross-linked beads; and    drying said cross-linked beads forming a porous chitosan crossed-linked resin bead.    
     
     
         17 . The smoke filtration media of  claim 16  wherein said cross-linking compound is glutaraldehyde.  
     
     
         18 . The smoke filtration media of  claim 16  wherein said cross-linking compound is glyoxal.  
     
     
         19 . A tobacco smoke filtration media obtained by the steps of: 
 dissolving chitosan in an acetic 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 precipitation bath has sodium hydroxide, water, 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 for about 1 hour to about 24 hours in a cross-linking solution 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 beads; and    drying said cross-linked beads forming a porous chitosan crossed-linked resin bead.    
     
     
         20 . The smoke filtration media of  claim 19  wherein said cross-linking compound is glutaraldehyde.  
     
     
         21 . The smoke filtration media of  claim 19  wherein said cross-linking compound is glyoxal.  
     
     
         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.  
     
     
         23 . The cigarette filter according to  claim 22 , wherein said filter is attached to a tobacco rod by tipping paper.  
     
     
         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.  
     
     
         25 . The cigarette filter according to  claim 22 , wherein said resin is incorporated in cigarette filter paper.  
     
     
         26 . A method of manufacturing 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; and    incorporating said filter media in a filter wherein said filter media removes said gaseous component of said gas mixture.    
     
     
         27 . The method according to  claim 26 , further comprising attaching said filter to a tobacco rod with tipping paper.  
     
     
         28 . The method according to  claim 26 , wherein said filter media 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.  
     
     
         29 . The method according to  claim 26 , wherein said cross-linking compound is glutaraldehyde.  
     
     
         30 . The method according to  claim 26 , wherein said cross-linking compound is glyoxal.  
     
     
         31 . The method according to  claim 26 , wherein said cross-linking compound is incorporated in a cavity of said filter.  
     
     
         32 . A method of removing a gaseous component of a gas mixture comprising passing said gas mixture in contact with a filter, wherein said filter has a reagent consisting essentially of at least one reactive functional group cross-linked to chitosan such that said reagent chemically reacts with said gaseous component of said gas mixture and removes said gaseous component from said gas mixture, wherein said functional group is selected from the group consisting of glutaraldehyde and glyoxal.  
     
     
         33 . The method according to  claim 32 , further comprising steps of generating said gas mixture and directing a gas stream containing said gas mixture through said filter such that said component of said gas mixture to be removed is chemically reacted with said reagent and prevented from reentering said gas stream.  
     
     
         34 . A tobacco-smoke filter comprising a chitosan resin having a reduced number of reactive amino groups.