Trichloroethylene adsorption by modified fibrous and granular activated carbons: An integration of aqueous phase, gas phase, and water vapor adsorption studies

The adsorbate-adsorbent interactions during the adsorption of hydrophobic contaminants by activated carbons from aqueous solutions were investigated. Various activated carbon precursors with different pore size distributions were subjected to different surface treatment pathways that produced carbons with different acidic and basic characteristics. The impact of surface chemistry and porosity of carbons on the trichloroethylene (TCE) adsorption was studied. The modified sorbents were used to performance gas phase water vapor and pure TCE vapor isotherms to examine water affinity and uptake of TCE in the absence of other molecules. TCE uptake was correlated with the carbon porosity and independent of carbon hydrophilicity. TCE uptakes of carbons were considerably enhanced after the heat treatment, while oxidation had the most unfavorable impact. Ammonia-treated carbons exhibited a significantly lower TCE uptake than the heat-treated carbons. Any increase in carbon surface polarity, either through oxidation or ammonia treatment, significantly inhibited uptake of TCE by activated carbons.