Degradation Characteristics of Carbon Tetrachloride by Granular Sponge Zero Valent Iron

Granular sponge zero valent iron (ZVI) was employed to degrade carbon tetrachloride (CCl 4 ). The effects of acidic washing, initial solution pH, and ZVI dosage on CCl 4 degradation were investigated. Results showed that CCl 4 was effectively removed by ZVI and approximately 75% of CCl 4 was transformed into chloroform through hydrogenolysis. The rate of chloroform transformation was slower compared to that of CCl 4 , resulting in chloroform accumulation. CCl 4 degradation was a pseudo first-order process. The observed pseudo first-order reaction rate constant ( k obs ) for CCl 4 and chloroform were 0.1139 and 0.0109 h −1 , respectively, with a ZVI dosage of 20 g/L and an initial CCl 4 concentration of 20 mg/L. Surface acidic washing had a negligible effect on CCl 4 degradation with ZVI. The k obs for CCl 4 degradation increased linearly with increasing ZVI dosage and the optimal dosage of ZVI was 20 g/L based on the surface area-normalized rate constants. The negative relationship between k obs and the solution pH indicated that the degradation of CCl 4 by ZVI performed better under weakly acidic conditions.