Keywords:Carbon tetrachloride, Sponge iron, Reductive dechlorination
Chlorinated hydrocarbons are the most prevalent groundwater pollutants that pose a risk to public health. The degradation of CCl4 by sponge iron and factors affecting degradation efficiency including acid washing, dosage and initial pH were investigated through batch experiments in this study. Results showed that CCl4 was effectively degraded by sponge iron and about 75 percent of CCl4 was transformed into chloroform (CF) by hydrogenolysis process. The rate of CF transformation was slower than that of CCl4, resulting in the CF accumulation. Surface acid activation showed slight influence on CCl4 degradation with ZVI. The CCl4 degradation reactions followed pseudo-first-order kinetics, and the apparent first-order rate constant (kobs) increased linearly with increasing ZVI dosage and the suitable dosage of 20g/L was indicated in terms of surface area-normalized rate constants (kSA). The kobs decreased with the increasing of pH value and the process indicated that the degradation of CCl4 had a better performance under weak acidic condition.