Removal of Malachite Green from Wastewaters by Bentonite-Based Photocatalytic Technology

Abstract

MgFe2O4-B/Ag3VO4 visible light active photocatalyst was successfully synthesized for thephotocatalytic decolorization of organic pollutants. Malachite green (MG) was selected as a model dyerepresenting those pollutant chemicals. The catalyst was characterized by X-ray diffraction (XRD), scanningelectron 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. Decolorizationyield and kinetic studies were traced by the help of a UV-Vis spectrophotometer. Kinetic model ofdecolorization was derived from Langmuir–Hinshelwood (L–H) model and found coherent to first orderkinetics. Catalysis reaction showed high dependency on pH especially out of 5-7 range which gave highdecolorization. Photocatalytic activity also depended on concentration with dual character in which highconcentration hindered the light coming to catalyst surface but on the other hand it supported the activityby boosting the dark adsorption resulting in a decolorization time changing from 40 to 100 min. After thereaction 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 alternativematerial for the removal pollution resources from wastewaters.