Removal of Malachite Green Dye from Aqueous Solution Using MnFe2O4/Al2O3 Nanophotocatalyst by UV/H2O2 Process

Background & Aims of the Study: Malachite Green (MG) is the most commonly usedsubstance for dying cotton, food & pharmacy industries, paper, leather and silk. Oninhalation it can cause difficult breathing, while on the direct contact it may causepermanent injury of the eyes of human and animals, burning sensations, nausea, vomiting,profuse sweating, mental confusion and methemoglobinemia; also it can causes cancer inlivers. The aim of this study is the removal of Malachite Green (MG) dye from aqueoussolutions, using MnFe2O4/Al2O3 nanophotocatalyst by UV/H2O2 process which was used asa low cost method.Materials & Methods: In this research, photocatalytic decomposition of malachite greenin water was done by nanocatalyst MnFe2O4/Al2O3 in discontinuous photoreactor under UVlight and the injection of H2O2. In order to identify and analyze the provided catalyst, SEMimage and XRD diffraction pattern were used. The effect of operational factors in thephotocatalytic decomposition of the desired pollutant such as pH, the initial thickness of thedye, the thickness of H2O2 and the quantity of the catalyst were investigated.Results: The finding showed that the right conditions for the elimination of the pollutantincluded pH equals 4, the initial thickness of the dye being 10 ppm, the thickness of H2O2being 250ppm, the amount of catalyst being 50mg, the Correlation Coefficient being 0.998and the dye removal was 94 percent at the end of the experiment. the reaction of Malachitegreen decomposition was in terms of kinetics investigated through integral method as well;also it showed the kinetic reaction is the first type and the constant speed rate isK=0.047Conclusions: According to the results, because of the complexity of dye structure,biological system was not able to remove the dye as efficient as hybrid system of advancedoxidation processes UV/H2O2 with nanophotocatalyst as an efficient way to remove theMalachite green dye from water solution is obtained that increases the decomposability oforganic materials. This way has proved to be able to decompose the hard compounds thatare resistant to decomposition.

Keywords:

Aqueous solution , Malachite green , Nanophotocatalyst , UV/H2O2 , Advancedtreatment , Iran