Abstract
The dechlorination of tetrachloroethylene or perchloroethylene (PCE) by Si(0) in the presence of Cu ion under various pH values was assessed to study the synergistic effect of Cu species on the PCE dechlorination by Si(0). The change in active species of Cu and Si under various pH values was characterized using XPS, electron probe microanalysis. The pseudo-first-order kinetics was applied to calculate the PCE dechlorination rate. The addition of 0.06 wt.% Cu ion enhanced PCE degradation significantly compared to its absence. A nearly complete PCE dechlorination was observed within 80 h. Unlike Pd, Pt, and Ni metals which can serve as catalysts for hydrogenation in the presence of H 2 gas, Cu can only enhance the electron transfer from Si surface to the pollutant. The increase in incubation time before the injection of Cu can activate the Si(0) surface, and, subsequently, enhanced PCE dechlorination rate. The inactivation of Si surface at high pH value in the presence of Cu(II) may be attributed to the formation of copper oxides. The Cu(II) ion in the solution would compete electrons with chlorinate hydrocarbon and then accelerated the oxidation of Si surface to silicon dioxide and lowered the PCE dechlorination rate.