ORGANIC COSOLVENT EFFECTS ON SORPTION KINETICS OF HYDROPHOBIC ORGANIC-CHEMICALS BY ORGANOCLAYS

Data obtained from batch kinetics sorption experiments for naphthalene and diuron using two organoclays [trimethylphenylammonium (TMPA)-clay and benzyldimethyltetradecylammonium (BDTDA)-clay] in aqueous and met hanol-water systems were analyzed with a first-order one-site mass tra nsfer model (OSMTM) to obtain kinetic parameters. The mass transfer co efficient (epsilon) exponentially decreased as the sorption coefficien t (K-p) increased, and a log-linear increase in epsilon was observed w ith an increase in the volume fraction of cosolvent (f(c)) in the syst em. Regression equations relating epsilon to f(c), measured in mixed s olvents, could be extrapolated to f(c) = 0 to obtain the coefficients in aqueous systems. The organic cosolvent effects on the sorption kine tics behavior of naphthalene and diuron depended on the sorbate struct ure, the cosolvent fraction, and the arrangement of the exchanged quat ernary alkylammonium ions in montmorillonite-clay interlayers.