Remediation of Organochlorine Pesticides Contaminated Soils by Surfactants Enhanced Washing Combined with Activated Carbon Selective Adsorption

Remediation of organochlorine pesticide (OCP)-contaminated soils is urgently required especially in China. The present study investigated the removal of OCPs from two soils by triton X-100 (TX-100)-enhanced washing coupled with powdered activated carbon (PAC) adsorption treatment of the solution. Two contaminated soils, including a silt clay contaminated with chlordene, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethanes (DDDs), and dichlorodiphenyltrichloroethane (DDT) and a sandy loam containing chlordanes and mirex, were selected. Effects of varied operating parameters, including TX-100 dosage, liquid/soil (L/S) ratio, and extraction time, on the contaminant removal were examined. For both soils, OCP removal was clearly enhanced with increasing TX-100 in extraction solution and L/S ratio. Meanwhile, the removal efficacy was also impacted by soil texture and characteristics and contents of the contaminants. Moreover, by using PAC as an absorbent, a significant decrease in the contaminants in the extraction solutions was detected, and TX-100 could be further reused. Our investigation suggests that surfactant-enhanced washing combined with activated carbon selective adsorption would be an alternative to remediate OCP-contaminated soils.