Ternary metal composite membrane FCMNCM enhances the separation of As(Ⅲ) in water through the multifunctional cooperation

More cases of arsenic contamination are reported globally, making the restoration of arsenic in water an active area of research. Especially, As(Ⅲ) is more difficult to remove than negatively charged As(Ⅴ) due to the presence of neutral H₃AsO₃ in the water, so to achieve efficient separation of As(Ⅲ) in water, it is very important to pre-oxidize As(Ⅲ) to As(Ⅴ). Herein, Fe-coated Cu⁰ doped MnO₂ nanowire membrane (FCMNCM) was successfully prepared to enhance the oxidation of As(Ⅲ) to As(Ⅴ) through the combination of superoxide anion (O₂^·-) and MnO₂ oxidation. Experimental results show that Cu⁰ activates oxygen to generate O₂^·-, the generated O₂^·- not only significantly enhances the conversion efficiency of As(Ⅲ) to As(Ⅴ) but also oxidize the Mn(Ⅱ)/Mn(Ⅲ) produced by the reduction of MnO₂ by As(Ⅲ) to Mn(Ⅳ) again to realize multi-channel oxidation of As(Ⅲ), and the maximum separation efficiency of As(Ш) can reach 99.34%. Acidic conditions are favorable for the separation of As(Ш), and carbonate and phosphate have a serious negative effect on As(Ⅲ) separation by competing for the active site. Anti-fouling and repeatability experimental show that FCMNCM is an environmentally friendly material with long service life and excellent reusability, it provides a new platform for As(Ⅲ)-containing sewage treatment.