Mechanism of carbon tetrachloride reduction in Fe(II) activated percarbonate system in the environment of sodium dodecyl sulfate

Abstract

This work innovatively found that Fe(II) activated sodium percarbonate (SPC) process could successfully degrade carbon tetrachloride (CT) in the environment of sodium dodecyl sulfate (SDS). CT degradation was remarkably accelerated to 87.2% at the optimum SPC/Fe(II)/CT molar ratio of 5/10/1 with the environment of 0.2 critical micelle concentration (CMC) SDS concentration. Fe(II) could effectively catalyze the decomposition of SPC to generate reactive oxygen species (ROSs). The results demonstrated that SDS enhanced the Fenton system and developed ROSs genertion. Hydroxyl radical (HO•), superoxide radical (O2−•), carbon dioxide radical (CO2−•), and singlet oxygen (1O2) were mainly generated in SPC/Fe(II) system under the condition of 0.2 CMC SDS, while CO2−• and 1O2 were the dominant active substances at 2.0 CMC SDS presence. The SPC/Fe(II) process performed much effective for the efficient degradation of CT at the acidic pH condition. The specific redox degradation pathway of CT started from the reduction of CT to •CCl3 through CO2−• and O2−• to form intermediates that were further dechlorinated by ROSs. In conclusion, the application of Fe(II) catalyzed SPC in the environment of SDS is a promising technology in converting the oxidation process into the simultaneous existence of oxidation and reduction process.