Photodecolorization of methylene blue over EGZrO2/EGZnO/EGFe2O3/HY photocatalyst: effect of radical scavenger

Abstract

The photocatalytic activity of methylene blue (MB) was investigated in aqueous solutions under solar radiation using electrogenerated metals supported on HY zeolite (EGZrO2/EGZnO/EGFe2O3/HY) catalyst. The prepared catalysts were examined using X-ray diffraction (XRD), transmission electron microscopy (TEM), and Brunnauer-Emmett-Teller surface area analysis (BET). An amount of 0.375 g L-1 EGZrO2/EGZnO/EGFe2O3/HY was found to be the optimum dosage for 10 mg L-1 MB, which gave almost complete photodecolorization of MB (99.5%) after 1 h of contact time at pH 9. Next, the effect of inorganic salts such as NaCl, Na2CO3, Na2SO4, and KI was also studied. It was found that the presence of the Cl- and CO3-2 ions obstructed the photodecolorization, but the presence of SO42- accelerated the reaction. The presence of I- ions did not affect much on the decolorization rate. Furthermore, the addition of H2O2 significantly enhanced the photodecolorization for the 50 mg L-1 of MB solution under similar optimum conditions. It was also found that the radical scavenging agents such as dimethyl sulfoxide (DMSO) and methanol (MeOH) suppressed the decolorization, with DMSO being the most effective. The simple preparation of the photocatalyst and low amount of metal loading required exhibits the great potential of the system that could be applied in textile or other industries wastewater treatment.