Cigarette filter

A cigarette filter comprising a reagent consisting essentially of at least one reactive functional group covalently bonded to a non-volatile inorganic substrate wherein the reagent chemically reacts with a gaseous component of a smoke stream to remove said gaseous component from said smoke stream, wherein said reagent is incorporated in cigarette filter pager and said filter paper is located within a free-flow filter.

A cigarette filter which comprises 3-aminopropylsilyl groups covalently bonded to silica gel.

A method of manufacturing a filter which is useful for removing a gaseous component of a gas mixture, comprising steps of:

• preparing a reagent consisting essentially of at least one reactive functional group covalently bonded to a non-volatile inorganic substrate;
• and
• incorporating the reagent in a filter wherein the reagent chemically reacts with a gaseous component of a gas mixture to remove said gaseous component from said gas mixture, wherein the functional group is an aminopropylsilyl group.

A method of manufacturing a filter which is useful for removing a gaseous component of a gas mixture, comprising steps of:

• preparing a reagent consisting essentially of at least one reactive functional group covalently bonded to a non-volatile inorganic substrate;
• and
• incorporating the reagent in a filter wherein the reagent chemically reacts with a gaseous component of a gas mixture to remove said gaseous component from said gas mixture, wherein the reagent comprises 3-aminopropylsilyl groups covalently bonded to silica gel.

A method of removing a gaseous component of a gas mixture, comprising passing the gas mixture in contact with a filter comprising a reagent consisting essentially of at least one reactive functional group covalently bonded to a non-volatile inorganic substrate such that the reagent chemically reacts with the gaseous component of the gas mixture and removes said gaseous component from said gas mixture, wherein the functional group is an aminopropylsilyl group, the functional group being effective to remove an aldehyde from the gas mixture.

A method of manufacturing a filter which is useful for removing a gaseous component of a gas mixture, comprising steps of:

• preparing a reagent by covalently bonding at least one reactive functional group to a non-volatile inorganic substrate so that said reagent is reactive with a preselected gaseous component of a gas mixture;
• and
• combining the reagent with an air permeable filter body such that the reagent is chemically reactive with the preselected gaseous component of a gas mixture, wherein the functional group is an aminopropylsilyl group and the inorganic substrate consists essentially of silica gel.