Layered double hydroxides as potential solid base for beneficial remediation of endosulfan-contaminated soils

Chlorinated pesticides in soils have been of a great concern due to their persistence, toxicity and bioaccumulation. This study deals with decomposition of enodsulfan substances by LDHs in suspension as a preliminary study to explore LDH potential for beneficial chemical remediation of the soils contaminated with chlorinated pesticides. Endosulfans decompose completely in the presence of NaOH or LDHs. However, endosulfan sulfate is hardly decomposed by NaOH, whereas it is decomposed quickly by LDHs. Within 15 min., the decomposition rate reaches to about 45%. CaFe-NO₃ LDH exhibits the highest decomposition rate. It is interesting that the decomposition accompanies the remarkable deterioration of LDH structure. No noticeable differences in the reaction products between NaOH and LDH treatments strongly suggest that decomposition of endosulfan substances takes place by base-catalyzed process through disintegration of LDH framework.