Journal of Hazardous Materials, Vol.286, 7-14, 2015
Degradation of carbon tetrachloride in aqueous solution in the thermally activated persulfate system
Thermal activation of persulfate (PS) has been identified to be effective in the destruction of organic pollutants. The feasibility of carbon tetrachloride (CT) degradation in the thermally activated PS system was evaluated. The experimental results showed that CT could be readily degraded at 50 degrees C with a PS concentration of 0.5 M, and CT degradation and PS consumption followed the pseudo-first order kinetic model. Superoxide radical anion (O-2(center dot-)) was the predominant radical species responsible for CT degradation and the split of C-Cl was proposed as the possible reaction pathways for CT degradation. The process of CT degradation was accelerated by higher PS dose and lower initial CT concentration. No obvious effect of the initial pH on the degradation of CT was observed in the thermally activated PS system. Cl-, HCO3-, and humic acid (HA) had negative effects on CT degradation. In addition, the degradation of CT in the thermally activated PS system could be significantly promoted by the solvents addition to the solution. In conclusion, the thermally activated PS process is a promising option in in-situ chemical oxidation/reduction remediation for degrading highly oxidized organic contaniinants such as CT that is widely detected in contaminated sites. (C) 2014 Elsevier B.V. All rights reserved.