Efficacy of quaternary ammonium groups based polyelectrolytes for the reduction of various pesticide formulations content from synthetic wastewater

Abstract

• Cationic polymers were studied for the removal of different commercial pesticides. • Lower optimum polymer dose was found for the samples with higher charge content. • A reduced pesticide removal degree was noticed for lower pesticide concentrations. • Zeta potential results indicate charge neutralization mechanism for pesticide removal. Cationic polyelectrolytes, synthetic (PCA) and dextran derivatives (D40-EtX) have been evaluated, for the first time, as flocculants for the separation of the commercial pesticides Novadim Progress -organophosphoric type (active ingredient Dimethoate), Decis and Karate Zeon - pyrethroid type (active ingredients Deltamethrin and lambda- Cyhalothrin, respectively) from synthetic wastewater. The investigated ionic polymer samples contain different amount of quaternary ammonium salts groups in the chain. The effects of settling time, polymer dose, ionic groups content, pesticides concentration on the separation efficacy have been investigated . The UV–Vis spectroscopy data indicate that the highest removal efficiency of pesticides (between 90 and 94% for Novadim Progress and between 86 and 94% for the pyrethroids insecticides) has been achieved by the polyelectrolytes with the highest charged groups content (higher than 90%). The charge neutralization mechanism had a noteworthy contribution to the pesticide removal as indicated by the zeta potential and particle size measurements. Slightly lower optimum polycation doses were found for lower pesticides concentrations.