Efficient oxidation of micropollutants by reactive FeMn hydr(oxy)oxides confined in membrane pores.

Manganese oxides with specific reactivity have attracted a great interest in pollutant removal, but are still challenged by the sluggish kinetics and metal release. This study proposes a feasible method to in situ synthesize reactive Fe(III)-Mn(III) hydr(oxy)oxides by simply modulating diffusion and redox reactions of Fe(II) and Mn(VII) in the confined PVDF membrane pores under ambient conditions. Without requiring any oxidant addition, the obtained multifunctional Fe-Mn/PVDF composite membrane showed rapid and efficient oxidation of various micropollutants. Influence of typical factors were examined, and the efficiency in authentic water matrices was also assessed. Reaction mechanism was further revealed, underlining the key role of spatial confinement in controlling the reactivity of FeMn hydr(oxy)oxides in pores of PVDF membrane. Furthermore, both Fe and Mn in the hydr(oxy)oxides help generate and stabilize Mn(III) species, which accounted for the high oxidization efficiency of contaminants. This study not only puts an insight into the attractive reactivity of FeMn hydr(oxy)oxides in confinement environment, but also provides a promising method to fabricate and manipulate multifunctional composite membrane for water purification under mild conditions.