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COMPETITIVE ADSORPTION OF VOCS AND BOM-OXIC AND ANOXIC ENVIRONMENTS
Citation:
Sorial, G. A., S. P. Papadimas, M. T. Suidan, AND T F. Speth*. COMPETITIVE ADSORPTION OF VOCS AND BOM-OXIC AND ANOXIC ENVIRONMENTS. WATER RESEARCH. Elsevier BV, AMSTERDAM, Netherlands, 28(9):1907-1919, (1994).
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Description:
The effect of the presence of molecular oxygen on the adsorption of volatile organic compounds (VOCs) in distilled Milli-Q water and in water supplemented with background organic matter (BOM) is evaluated. Experiments are conducted under conditions where molecular oxygen is present in the test environment (oxic adsorption), and where oxygen is absent from the test environment (anoxic adsorption). Adsorption isotherms for tetrachloroethylene (PCE) and trichloroethylene (TCE) in Milli-Q water showed no impact of the presence of oxygen on their adsorption behavior, while adsorption isotherms for cis-1,2-dichloroethane (DCE) showed higher capacities under oxic conditions. VOC adsorption isotherms in BOM are conducted for three initial concentration sets of VOCs and two initial concentration sets of BOM. VOC isotherms collected under oxic and anoxic conditions in water supplemented with BOM showed that by keeping the initial concentration ratio of VOCs to BOM constant, the adsorption behavior of the VOC is very similar. VOC isotherms in BOM conducted under oxic conditions generally showed lower capacities than the anoxic isotherms. The ideal adsorbed solution theory (IAST) successfully predicted the VOCs anoxic adsorption isotherms in BOM. However, the IAST model did not predict the VOCs oxic adsorption isotherms in BOM. Analysis of the data was conducted using the isotherm parameters of the VOCs in Milli-Q water, and correlation parameters using a four fictive component approach for the BOM. The poor agreement between experimental data and model predictions obtained for the oxic isotherms is attributed to the presence of molecular oxygen which promotes conglomeration of BOM on the surface of carbon.
