Cigarette filter - contains a molecular sieve of selected pore size

摘要

Filter for cigarettes etc. contains natural or synthetic molecular sieves of formula M2/nO, Al2O3, xSiO2, yH2O (where M is H, alkali(ne earth) or transition metal of valency n) of the zeolite gp. having pore dia. of 4-25 angstroms pref. 6 angstroms. Particle size is 80-250 mu. The sieve may be modified by exchange of the original cation with H, Li, K etc.