Application of TiO2/ZnFe2O4/glycine nanocatalyst to the treatment of methyl orange dye from aqueous solution: Impacts of dissolved mineral salts on dye removal efficiency

This study aims to remove one of the frequently used dyes in textile industries, i.e., Methyl Orange, from polluted water with TiO2/ZnFe2O4/glycine catalyst under UV irradiation. The TiO2/glycine/ZnFe2O4 nanocatalyst was synthesized using the sol-gel method and characterized by XRD, XRF, FT-IR, UV-visible DRS, BET, FE-SEM, and EDX analyses. Process factors including initial dye concentration (10-30 ppm), catalyst dosage (0.5-1.5 g/L), initial pH solution (3-11), and irradiation time (30-150 min) were investigated by central composite design. The removal efficiency of methyl orange was 80% under the optimal conditions, i.e., dye concentration of 20 ppm, catalyst dosage of 1 g/L, irradiation time of 120 min, and pH = 6.5. The effects of mineral salts such as NaHCO3, NaCl, Na2SO4, KCl, MgSO4, and CaCl2 with the concentrations of 50-800 ppm on the dye removal efficiency were evaluated under optimal conditions. Although low concentrations of NaCl, KCl, and CaCl2 had adverse effects on MO removal efficiency, the dye removal efficiency was enhanced at their high levels (RNaCl: 800 = 74:52%). An increase in the concentrations of MgSO4 and Na2SO4 produced deactivation effects on the dye removal efficiency and reaction rate constant (MgSO4 deactivation: 36%). The pollutant removal efficiency and reaction rate constant increased using NaHCO3 (RNaHCO3: 800 = 82:4% and kNaHCO(3): 800 = 20:84 day 1). (C) 2021 Sharif University of Technology. All rights reserved.