| Trichloroethene (TCE) is a chlorinated solvent that is a major environmental contaminant of soils and groundwater, and its interactions with minerals play a key role in the fate and transport of TCE. This molecular simulation study is complementary to experimental work on TCE sorption to hydrated zeolites. This research is the first to perform grand canonical Monte Carlo simulations of competitive TCE and water adsorption by zeolites. Potential energy parameters for the system were improved, and the resulting force field reproduces the properties of TCE, water, and aluminosilicates. For more complex systems, the force field predictions matched experimental data for water sorption by zeolite Y and for TCE sorption to hydrated zeolite Y. The structural and energetic features of adsorbates were examined in detail. Water and TCE domains remain quite separate in the zeolite, with very little mixing of the two species even when clusters of each are present in the same pore. Water-TCE competition was examined in zeolites that were empty or pre-equilibrated with either water or TCE. Two commercial force fields were also tested but our own modeling results were in far better agreement with the overall experimental data and especially the water sorption data. |
