Liquid and vapor phase adsorption of chlorinated volatile organic compounds on hydrophobic molecular sieves

This work focused on the potential application of various hydrophobic molecular sieves for the sorption of four model chlorinated volatile organic compounds (CVOCs, i.e., chloroform, trichloroethylene, tetrachloroethylene, and carbon tetrachloride) from dilute liquid water streams. Results obtained thus far have shown that silicalite-l has a high affinity for these CVOCs, higher in fact than Centaur(R) activated carbon, used as a benchmark in this study. Loading results for trichloroethylene from both liquid and vapor phase indicated that the liquid phase did not penetrate the pores of silicalite-1, while the solution did penetrate the pores of Centaur(R) and a dealuminated NaY used for comparison. Finally, three definitions from the literature for the "hydrophobicity" of molecular sieves were considered. An alternative definition for hydrophobicity is introduced here, which is easy to determine and is based on water retention. (C) 2000 Elsevier Science B.V. All rights reserved.