Pesticides Removal by Filtration over Cactus Pear Leaves: A Cheap and Natural Method for Small-Scale Water Purification in Semi-Arid Regions

This study aims to examine the efficiency of Opuntia ficus-indica for removing organochlorine pesticides from surface waters. Adsorption properties such as size, dose, and time of O. ficus-indica for aldrin, dieldrin, and dichlorodiphenyltrichloroethane (DDT) were studied through stirring and column methods. Because of their high affinity and swelling characteristics, dried O. ficus-indica was studied in stirring while fresh unpeeled O. ficus-indica was applied in both stirring and column experiments and proved to be well-suited to column application. Before removing pesticides, the column was flashed with distilled water eliminate the turbidity and smell from fresh unpeeled cactus. The removal of pesticides increased with an increasing adsorbent dose and decreased with adsorbent particle sizes. The optimum adsorbent dose is 10g for dried and 15g for fresh unpeeled O. ficus-indica. The experimental results show that O. ficus-indica possesses strong adsorption ability for aldrin, dieldrin, and DDT, and the adsorption isotherm data obeyed the Freundlich model. The results of our small-scale experiments suggest a strong potential to develop local small-scale water treatment units that can be used at the level of individual households or local communities, using a widely available adsorbent. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.status: publishe