Influence of manganese-substitution on adsorption properties of BiFeO₃ onto the elimination of methyl orange

Herein, the BiFeO3 was modified by substituting varying manganese (Mn) concentration to improve the efficacy of eliminating methyl orange (MO), a water-soluble carcinogenic azo dye was presented. To examine the structure, morphology and band gap characteristics of the as-synthesised Mn-BiFeO3 nanocatalyst were characterised using various techniques including XRD, FESEM with EDX, FTIR, UV-vis DRS, and BET. Subsequently, parameters affecting the removal performance, such as adsorbent dosage (0.02-0.10 g), initial dye concentrations (10-60 mg/L), initial pH (1-13), percentage mol of manganese substitution (0-30%), and reusability of the adsorbent, were examined in detail. The specific surface area increases with doping from 6.829 to 13.063 m(2)/g, leading to enhanced adsorption capacity of manganese-substituted BiFeO3 as opposed to pristine BiFeO3. Adsorption kinetics was found to follow the pseudo-second-order kinetic model, while the adsorption equilibrium data obeyed the Freundlich isotherm model with a maximum adsorption capacity of 25.2 mg/g at 298 K. Interestingly, the catalyst showed more than 95% adsorption even after three consecutive cycles and therefore could be a good candidate for wastewater remediation.