Pathway and Kinetic of Dechlorination of Trichloroethylene in Water by Supported Nanoscale Bimetallic Fe-Cu Particles

Abstract

In this paper, exfoliated graphite supported nanoscale Fe-Cu is synthesized by aqueous-phase reductive method. The effect trichloroethene (TCE) reduction by the supported nanoscale Fe-Cu bimetal is researched in the batch experiments. Kinetics studies show that the reduction of TCE process obeys pseudo-second-order kinetics. The kinetic constants of TCE reduction by supported nano bimetal are measured at different nano Fe0 dosage and Cu content on bimetal in this study. When the dosage of supported nano Fe0 in bimetal with 4wt% Cu is 1.25g/L in reaction solution, the kSA of dechlorination reaction for TCE is higher than other nano Fe0 dosage. The dechlorination speed becomes lower as well as kSA and kobs decreasing with increasing the Fe0 dosage. Supported Fe-Cu bimetal with 4wt% Cu content exhibits the best dehalogenation effect than those with other contents of Cu. The generation of H2 and effect of Cu analysis influence the TCE dechloriation and hydrogenation in the surface of bimetal to a different extent. Excess nano Fe0 existing in the reaction system can generate plenty of H2 as well as increasing the solution pH value so that decrease the surface concentration of bimetal reactive sites and then hinder the TCE dechlorination in surface of bimetal. Cu as catalysis metal could accelerate the process of TCE dechlorination and hydrogenation.