Degradation of organochlorine pesticides (OCPs) in water by iron (Fe)-based materials

This study employees iron (Fe)-based materials which contain zero valent iron (Fe0) and magnetite (Fe3O4) for degradation of organochlorine pesticides (OCPs), such as DDT, lindane (γ-HCH) and aldrin, in water. The degradation kinetics rate, effect of iron (Fe)-based materials dosage, chloride ion (Cl−) mass balance and degradation products are investigated. The results show that iron (Fe)-based materials successfully degrade OCPs in water. After 12 h reaction, the degradation of γ-HCH, p,p′-DDT and aldrin at the initial concentration of 0.001 mg L−1 in water were found to be 100%, 81%, and 79%, respectively. Degradation rate order from the highest is γ-HCH, followed p,p′-DDT, and aldrin which related to their physicochemical properties. The degradation rate decreased with the increasing initial concentration of OCPs from 0.00005 mg L−1 to 10 mg L−1 in water. Increasing the amount of iron (Fe)-based materials clearly improves the degradation rate. Moreover, increasing free chloride ion (Cl−) for elapsed time suggests that OCPs are degraded into lower molecular compounds through dechlorination process. In addition, several degradation products of p,p′-DDT are detected, and degradation pathways are proposed, however, degradation products of γ-HCH and aldrin could not be identified in this study.