Remediation of organophosphate pesticide-contaminated soil using soil washing and advanced oxidation processes

Large numbers of contaminants such as polycyclic aromatic hydrocarbons, pesticides and chlorophenols pass through sediments and soil, causing a giant danger to human health and ecosystem. To remediate the soil contaminated with these pollutants, various methods have been proposed including coupled soil washing with Fenton or Sono-Fenton process. In this study, non-ionic surfactants [Tween 85 AND linear alkylbenzene sulfonates (LASs)] were used for the removal of chlorpyrifos (organophosphate pesticide). The optimal conditions for LAS surfactant were found to be a concentration of 2.5 g/L with 20/1.5 ratio (liquid/solid), 360 min operation time and 120 rpm washing speed in room temperature; while 1 g/L Tween 85 concentration was more effective at 20:1 ratio (liquid solid), 360 min operation time and 60 rpm washing speed in room temperature, respectively. The results imply that combining both Tween 85 and LAS can be an effective way to remove large amounts of contaminants from soils quickly without damaging them further or harming humans who might come into contact with it afterward. The results of the experimental study on soil washing and Fenton/Sono-Fenton suggest that these two processes combined can be an effective way to remediate soils contaminated with chlorpyrifos. This combination was shown to provide superior results for both remediation and recovery of surfactants used in the cleaning process.