SELECTIVE FILTRATION DEVICE

摘要

Disclosed is a filter for tobacco smoke composed of at least one layer of a wet-formed absorbent fibrous nonwoven composite structure containing: 1) from about 30 to about 65 percent, by weight, of pulp fibers forming a matrix having a first exterior surface and a second exterior surface; and 2) about 35 to about 70 percent, by weight, of activated carbon integrated into the matrix of pulp fibers such that the concentration of activated carbon adjacent the first exterior surface is at least about 60 percent, as determined by optical image analysis, and the concentration of activated carbon adjacent the second exterior surface is less than about 40 percent, as determined by optical image analysis, so that the filter is adapted to selectively reduce the C3-C4 carbonyl component of conventional tobacco smoke at least about 25 percent more than a conventional cellulose acetate filter for an identical tobacco smoke. Also disclosed is a method of making the filter.