Effect of pH on PCP Remediation by Smectite Supported Pd / Fe

Abstract

Due to its influence on iron corrosion and involvement in dechlorination reaction, the concentration of H+ is crucial to the reactivity and efficiency of nanosized Pd /Fe. In this study, PCP dechlorination by smectite-templated Pd/Fe was studied and the effect of pH on PCP dechlorination was investigated in detail. The reaction rate constant is critically dependant on the reaction pH over the range 6.0~10.0. The dechlorination rate increases rapidly with decreasing the reaction pH value when the pH is 6.0~8.0. The rate change is up to 3.346 folds with decreasing of per pH unit while it decreases down to 0.3338 when pH is in the range 8.0~10.0. The reductive efficiency of zero-valent iron (ZVI) was further investigated by spiking excess PCP in the reaction system. The maximal reaction efficiency of ZVI for PCP dechlorination attains to 78% when pH is 9.0. The difference between the dechlorination rate and reductive efficiency with respect to reaction pH suggest that ZVI could not be effectively utilized to reduce PCP under acidic condition.