STP1205

    Small Closed-Chamber Measurements for the Uptake of Trichloroethylene and Ethanol Vapor by Fibrous Surfaces

    Published: Jan 1993


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    Abstract

    Recent efforts to quantify the effect of sorption on indoor concentrations of volatile organic compounds (VOCs) have indicated that indoor surfaces may behave as reservoirs for VOCs emitted from other sources. For the surface materials of greatest interest indoors, the interactions of airborne pollutants with such surfaces have not been very extensively studied. In this study, partition coefficients, defined as the ratio of the sorbed-phase to vapor-phase equilibrium concentrations, have been measured for sorption of trichloroethylene (TCE) and ethanol (EtOH) vapors by a variety of fibrous or polymeric surfaces. Several of these, nylon, wool, polypropylene, jute, and styrene-butadiene rubber (SBR), are important components of carpet. Glass, cotton, and polyester fibers have also been included. Results indicate that for TCE, sorption to the carpet backing materials polypropylene and SBR is more significant than sorption to the nylon or wool pile fiber; partition coefficients for the former are about 300 cm3/g, while values for nylon are approximately 10 to 20 cm3g. The opposite was found to be true for EtOH, for which partition coefficients with respect to nylon fiber are on the order of 1000 cm3/g, in contrast to those measured with respect to polypropylene or SBR, that are in the range of 20 to 40 cm3/g. Because of the concentration and temperature dependence of the observed sorption effects, an explanation based on an adsorption mechanism was reasonable in most cases. Nevertheless, absorption may also play a role in partitioning, particularly for VOCs and polymers with similar solubility parameters, such as for TCE with respect to polypropylene or SBR. Because various components of a composite material such as carpet may exhibit very different affinities for a single compound as well as different mechanisms of interaction, models for sorption using first-order kinetics may not adequately describe sorption and desorption of VOCs indoors.

    Keywords:

    indoor air quality, heterogeneous reactions, gas, vapor, sorption, equilibrium, isotherms, specific surface area


    Author Information:

    Borrazzo, JE
    Research assistant and professor, Carnegie Mellon University, Pittsburgh, PA

    Davidson, CI
    Research assistant and professor, Carnegie Mellon University, Pittsburgh, PA

    Andelman, JB
    Professor, University of Pittsburgh, Graduate School of Public Health, Pittsburgh, PA


    Paper ID: STP13098S

    Committee/Subcommittee: D22.05

    DOI: 10.1520/STP13098S


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