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SORPTION AND REEMISSION OF FORMALDEHYDE BY GYPSUM WALLBOARD
Citation:
Chang, J. SORPTION AND REEMISSION OF FORMALDEHYDE BY GYPSUM WALLBOARD. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/A-93/078 (NTIS PB93180917), 1992.
Description:
The paper gives results of an analysis of the sorption and desorption of formaldehyde by unpainted wallboard, using a mass transfer model based on the Langmuir sorption isotherm. he sorption and desorption rate constants are determined by short-term experimental data. ong-term sorption and desorption curves are developed by the mass transfer model without any adjustable parameters. ompared with other empirically developed models, the mass transfer model has more extensive applicability and provides an elucidation of the sorption and desorption mechanism that empirical models cannot. he mass transfer model is also more feasible and accurate than empirical models for applications such as scale-up and exposure assessment. or a typical indoor environment, the model predicts that gypsum wallboard is a much stronger sink for formaldehyde than for other indoor air pollutants such as tetrachloroethylene and ethylbenzene. he strong sink effects are reflected by the high equilibrium capacity and slow decay of the desorption curve.
