Removal of Malachite Green from Waste Waters by Bentonite Based Photocatalyst Technology

Abstract

MgFe2O4-B/Ag3VO4 visible light active photocatalyst was successfully synthesized for the photocatalytic decolorization of organic pollutants. Malachite green (MG) was selected as a model dye representing those pollutant chemicals. The catalyst was characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS). Malachite green (MG) decolorization was carried out by visible light irradiation of a 105 W tungsten light source. Decolorization yield and kinetic studies were traced by the help of a UV-Vis spectrophotometer. Kinetic model of decolorization was derived from Langmuir–Hinshelwood (L–H) model and found coherent to first order kinetics. Catalysis reaction showed high dependency on pH especially out of 5-7 range which gave high decolorization. Photocatalytic activity also depended on concentration with dual character in which high concentration hindered the light coming to catalyst surface but on the other hand it supported the activity by boosting the dark adsorption resulting in a decolorization time changing from 40 to 100 min. After the reaction was completed, powders of catalyst were effortlessly removed from the medium by a magnet bar. It was shown that MgFe2O4-B/Ag3VO4 photocatalyst has a potential to be simple and efficient alternative material for the removal pollution resources from wastewaters.