SORPTION OF TRICHLOROETHYLENE ONTO A ZEOLITE ACCOMPANIED BY METHANOTROPHIC BIOTRANSFORMATION

The rate and extent of trichloroethylene (TCE) sorption from aqueous p hase onto a synthetic hydrophobic zeolite, silicalite, were measured. Equilibrium sorption fit the Langmuir isotherm with parameters of Q(o) = 201 mg of TCE/g of silicalite and b = 0.52 L/mg. Rate studies showe d that TCE uptake by silicalite was rapid (equilibrium approached with in 25 min) as was desorption following perturbation of equilibrium by chloroform (CF) addition to the aqueous phase. The availability of sor bed TCE for cometabolic transformation by methanotrophic bacteria was evaluated, and a model was developed based upon the hypothesis that th e TCE transformation rate is proportional to the concentration of TCE in solution and independent of the mass of sorbed TCE. A comparison be tween experimental and model results for concurrent sorption/biotransf ormation supported the validity of the hypothesis and model assumption s. In the presence of silicalite, the methanotrophic transformation of solution-phase TCE induced desorption of TCE from the silicalite, res ulting in bioregeneration of the sorption sites. The potential for usi ng silicalite in an advanced waste treatment process incorporating bio regeneration is discussed.