Adsorption removal of Mn2+ and NH4+–N from electrolytic manganese metal wastewater by modified phosphate ore flotation tailings

Abstract

Electrolytic metal manganese wastewater (EMMW) is industrial wastewater produced in the process of producing electrolytic metal manganese, which contains Mn²⁺ and NH₄⁺–N pollutants. How to deal with low concentrations of Mn²⁺ and NH₄⁺–N from EMMW is an urgent problem for electrolytic manganese enterprises. In this study, Mn²⁺ and NH₄⁺–N were removed via adsorption by modified phosphate ore flotation tailings (MPOFTs). The results indicated that the concentration of Mn²⁺ and NH₄⁺–N in the EMMW decreased from 165 mg L⁻¹ to 0.001 mg L⁻¹ and from 70 mg L⁻¹ to 1.73 mg L⁻¹, respectively, when the solid–liquid ratio of MPOFTs to EMMW was 1 : 200, the reaction temperature was 323 K, the reaction time was 2.5 h and the initial solution pH was 9.0. The adsorption process was more consistent with the pseudo-first-order adsorption kinetic model and Weber's intraparticle diffusion model, and the results showed that this adsorption reaction was an endothermic reaction. This study provided a new research idea for EMMW and POFT treatment and disposal.