The preparation of Co/γ-Al2O3 and treatment of cartap pesticide wastewater by microwave catalytic oxidation

Abstract

Cartap is a moderately toxic insecticide, widely used because of its high efficiency, rapidness, long duration, and broad insecticidal spectrum. The production of cartap has so many synthetic steps and complex intermediate products, which results in serious environmental and health risks for the cartap containing wastewater. However, there are few studies on the treatment of cartap bearing wastewater. Herein, we prepared the catalyst by using γ-Al2O3 as a support, loaded by single metal (Cu, Fe, Co) through the dipping-sedimentation method. Then we characterized the catalysts by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS). Considering the treatment efficiency, experimental conditions, and cost reductions, Co/γ-Al2O3 was found to be the best catalyst. Results demonstrated that the Co/γ-Al2O3 catalyst has thermal stability, sintering resistance, and a certain mechanical strength. The optimum experimental conditions were as follows: pH — 6, microwave power — 300 W, H2O2 dosage — 0.2 mL, and catalyst dosage — 0.5 g. Based on these experimental results, we proposed plausible degradation pathways for cartap removal by microwave-responsive catalysts technology.