Removal and Photodegradation of Metolachlor Herbicide Using Polyelectrolyte Multilayer Membranes

The study illustrates the use of polyelectrolyte multilayer (PEM) membranes prepared with weak/strong polyelectrolyte combination of poly(ethyleneimine)/chondroitin sulfate A (PEI/CS) for the removal of metolachlor (MTR) from water samples. The proposed PEM membranes were characterized by chemical, physical, thermal, and morphological properties. The removal of MTR herbicide by PEI/CS multilayer deposited on a microfiltration polyamide membrane was found to be efficient with a retention rate of about 96.46% for 8 bilayers sat an excellent permeate flux of 6.27 m³/m² day. The photodegradation of metolachlor which got trapped in PEMs in the presence of riboflavin (Rb) sensitizer was investigated at various concentrations. A comparative study on photo-elimination of MTR without the presence of Rb was also done. The degradation time was greatly shortened from more than 1 h for direct photolysis to 5–15 min depending on the initial concentration of the sensitizer. The degradation of metolachlor in the presence of Rb as well as direct photolysis was also experimentally studied.