Optimization of preparation conditions of sulfate-reducing bacteria (SRB) immobilization particles strengthened by maifanite and its treatment of wastewater containing Mn 2+

According to the characteristics of acid mine drainage (AMD) solution, such as extremely low pH, rich SO42−, and Mn2+ pollution ions. In this study, maifanite, bagasse, and sulfate-reducing bacteria (SRB) were used as research objects based on microbial immobilization technology. Response surface methodology was used coupled with the Box–Behnken design. The type, dosage, and particle size of maifanite were used as independent variables. The pH, oxidation-reduction potential, total Fe (TFe) removal efficiency, Mn2+ removal efficiency, SO42− removal efficiency, and COD release amount of maifanite-reinforced SRB-immobilized particles were used as response values to optimize the preparation parameters of maifanite-reinforced immobilized particles, and the adsorption characteristics were analyzed. The results showed that the optimal conditions for the preparation of maifanite-reinforced SRB-immobilized particles were as follows: the type, dosage, and particle size of maifanite were Dengfeng maifanite, 0.1 g and 200–300 mesh, respectively. The surface pores of AMD were reduced and FeS, MnS, Fe(OH)3, Mn(OH)2 appeared after treated with maifanite, bagasse, and SRB. The reduction process of SO42- by maifanite-enhanced SRB-immobilized particles conformed to the first-order kinetics, and the adsorption process of Mn2+ conformed to the McKay pseudo-second-order kinetic model and the Freundlich isothermal adsorption model.