Evaluation of enhanced soil washing process and phytoremediation with maize oil, carboxymethyl-β-cyclodextrin, and vetiver grass for the recovery of organochlorin...

Abstract

Abstract An innovative ex situ soil washing technology was developed in this study to remediate organochlorine pesticides (OCPs) and heavy metals in a mixed contaminated site. Elevated temperature (60 C) combined with ultrasonication (40 kHz, 20 min) at 50 mL L− 1 maize oil and 45 g L− 1 carboxylmethyl-β-cyclodextrin were effective in extracting pollutants from the soil. After two successive washing cycles, the removal efficiency rates for total OCPs, mirex, endosulfans, chlordanes, Cd, and Pb were approximately 94.7%, 87.2%, 98.5%, 92.3%, 91.6%, and 87.3%, respectively. Cultivation of vetiver grass and addition of nutrients for 3 months further degraded 34.7% of the residual total OCPs and partially restored the microbiological functions of the soil. This result was indicated by the significant increase in the number, biomass C, N, and functioning diversity of soil microorganisms (p …