Degradation Behaviors and Accumulative effects of Coexisting Chlorobenzene Congeners on the Dechlorination of Hexachlorobenzene in soil by nanoscale zero-valent iron

Abstract

Abstract It is well known that many chlorinated organic pollutants can be dechlorinated by nanoscale zero-valent iron. However, in the real chlorinated organic compounds contaminated soil, high chlorinated organic pollutants and low chlorinated organic pollutants often coexist and their dechlorination behaviors are poorly known, such as hexachlorobenzene. In this work, the degradation behaviors of three coexisting chlorobenzene congeners pentachlorobenzene (PeCB), 1,2,4,5-tetrachlorobenzene (1,2,4,5-TeCB) and 1,2,4-trichlorobenzene (1,2,4-TCB) and the influence of initial pH and reaction temperature on the dechlorination of HCB in HCB-contaminated soil by nanoscale zero-valent iron were studied. The amount and extent of accumulated coexisting chlorobenzenes was analyzed under different environmental conditions. The results indicate that nanoscale zero-valent iron can improve the degradation efficiency of high-toxic chlorinated benzenes and reduce the accumulative effects of high-toxic chlorinated benzenes on dechlorination of HCB. The accumulative effects of three coexisting chlorobenzene congeners on the dechlorination of HCB were ranked as follows: 1,2,4-TCB > 1,2,4,5-TeCB > PeCB.