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AEROSOL FILTRATION BY SORBENT BEDS
Citation:
Kogan, V., R. Coutant, M. Kuhlman, AND R. Lewis. AEROSOL FILTRATION BY SORBENT BEDS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-95/247.
Description:
Fixed beds of sorbent media are used for the evaluation of polynuclear aromatic hydrocarbons (PAH) present in air. wo-stage sampling and separate extraction and analyses of PAH associated with aerosol particles and those present in the vapor state are usually performed. he ability of commonly used sorbents to retain particulate matter introduces a potential for reducing the time and cost of PAH evaluation procedures. he filtration efficiency of three sorbent media, Florisil, XAD-2, and polyurethane foam (PUF), for particles in 0.1 to 1 um size range was studied using air flow rates from 4 to 250 1/min through a PS-1 sorbent cartridge. heoretical considerations were used to identify the principal filtration mechanisms and to assess the predictability of the aerosol filtration performance of sorbent filters. he results of this study indicate XAD-2 to be an efficient filtration medium owing to the electrostatic enhancement of capturing and retaining aerosol particles. s a result of theoretical considerations, Brownian diffusion and inertial deposition were found to be major iltration mechanisms accompanied by electrostatic effects. hile the efficiency of the diffusional deposition mechanism was reasonably well predicted with available theories, modeling of submicron particle impaction at higher fluid velocities appeared to be inadequate. urther developments are suggested to improve our understanding of filtration phenomena in sorbent beds under high flow rate conditions.