Cigarettes and cigarette filters including activated carbon for removing nitric oxide
Filters and cigarettes include an activated carbon sorbent capable of selectively removing nitric oxide from mainstream tobacco smoke. Methods for making cigarette filters and cigarettes using the activated carbon sorbent and methods for treating mainstream tobacco smoke produced by smoking a cigarette comprising the sorbent are also provided.
1. A cigarette filter comprising an activated carbon sorbent, wherein a majority of the pores of the activated carbon sorbent have a size of less than about 30 Å, the activated carbon sorbent contains pores having a D-R micropore volume of from about 0.2 cm 3 /g to about 1.0 cm 3 /g in the pore size range of from about 5 Å to about 10 Å and pores having a D-R micropore volume of from 0.33 cm 3 /g to 0.61 cm 3 /g in the pore size range of from 10 Å to 20 Å, and the activated carbon sorbent is capable of removing nitric oxide from mainstream tobacco smoke, wherein the activated carbon sorbent is in the form of spherical beads.
2. The cigarette filter of claim 1 , wherein (a) a majority of the pores of the activated carbon sorbent have a size of from about 5 Å to about 20 Å; (b) the activated carbon sorbent has a BET surface area of from about 1000 m 2 /g to about 3,000 m 2 /g; or (c) the pores of the activated carbon sorbent that have a pore size of from about 5 Å to about 10 Å have a D-R micropore volume of from 0.3 cm 3 /g to about 1.0 cm 3 /g, and the activated carbon sorbent has a specific surface area of about 1000 m 2 /g to about 2,000 m 2 /g.
3. The cigarette filter of claim 1 , wherein (a) the beads have a substantially uniform diameter; or (b) the beads are of at least two different size fractions.
4. A cigarette comprising a cigarette filter according to claim 1 .
5. The cigarette of claim 4 , which is a non-traditional cigarette.
6. The cigarette filter of claim 1 , further comprising catalyst material capable of catalyzing the reaction of nitric oxide to N 2 and O 2 and/or to NO 2 .
7. The cigarette filter of claim 6 , wherein (a) the catalyst is Fe 2 O 3 and/or Fe 3 O 4 ; (b) the catalyst is nano-sized; (c) the catalyst is provided on the activated carbon sorbent; or (d) the activated carbon sorbent and the catalyst are in a physical mixture.
8. A cigarette comprising a cigarette filter according to claim 6 .
9. The cigarette filter of claim 1 , wherein the beads are of at least two different size fractions.
10. The cigarette filter of claim 1 , wherein the activated carbon sorbent contains pores having a D-R micropore volume of from about 0.2 cm 3 /g to about 0.31 cm 3 /g in the pore size range of from about 5 Å to about 10 Å.