Photocatalytic degradation kinetics of unsymmetrical dimethylhydrazine in aqueous solution by Fe³⁺ doped Bi₂O₃

The Fe³⁺ doped Bi₂O₃ photocatalyst was prepared by sol-gel method. The photocatalytic degradation experiment was carried out using unsymmetrical dimethylhydrazine (UDMH) simulated wastewater as the target pollutant. The results showed that Fe³⁺ doping significantly improved the degradation efficiency of UDMH with an optimum doping concentration of 2.0%. The reaction kinetics study indicated that the reaction was heterogeneously catalyzed and the kinetic fitting results were consistent with pseudo first-order reaction kinetics model. According to the results of linear fitting, the kinetic reaction rate constant of Fe³⁺ doped Bi₂O₃ (2.0%) was the largest, about 1.9 times as much as that of undoped Bi₂O₃. Finally, a possible mechanism was proposed to explain the enhanced photocatalytic activity. (paper)