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.