Mn3O4-FeS2/Fe2O3 composite as peroxidase-mimics for the degradation of Bisphenol A

Abstract

Due to the benefits of artificial peroxidase-like enzymes, Flower-like Mn3O4-FeS2/Fe2O3 composites with multiple active sites prepared by a one-step solvothermal method.The synergistic cyclic reaction between Mn and Fe on the catalyst surface enhances the generation of active radicals, which together promote the efficient degradation of BPA. In the presence of hydrogen peroxide (H2O2), Mn3O4-FeS2/Fe2O3 could generate hydroxyl radicals (·OH) and superoxide radicals (·O2-) in buffer solution of pH=4.5 and catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to blue oxidation products (ox TMB). The steady-state kinetic constants (Km) of TMB and H2O2 were obtained by Michaelis-Menten and Lineweaver-Burk models, which are 1.34 mM and 1.00 mM, respectively. This reveals the nice catalytic efficiency of Mn3O4-FeS2/Fe2O3 as enzyme mimics. Under the condition of 10 mg Mn3O4-FeS2/Fe2O3 catalyst, 100 μL H2O2 and pH = 4.5, the degradation efficiency of Bisphenol A (BPA) reaches 100 % when treating 40 mL of 50 mg L−1 BPA for 30 min at room temperature. Moreover, after 5 cycles of degradation, the BPA degradation efficiency of 85.8 % was still maintained. Therefore, the as-prepared Mn3O4-FeS2/Fe2O3 sample could potentially be applied in wastewater treatment.