Reversible filtration redox of methylene blue in dimethylsulfoxide by manganese oxide loaded carbonaceous nanofibrous membrane through Fenton-like oxidation

[Display omitted] The reversible redox of methylene blue in organic solvents was highly attractive, yet was rarely reported. In this study, we realized the continuous filtration redox of methylene blue (MB) in dimethylsulfoxide (DMSO) through Fenton-like oxidization by using MnO2 loaded carbonaceous nanofibrous membrane (cPAN-MnO2). The carbonaceous nanofibrous membrane (cPAN) was fabricated through electrospun of polyacrylonitrile and subsequent carbonization. The obtained cPAN nanofibrous membrane showed excellent stability in polar DMSO. MnO2 can be readily coated on cPAN nanofibers through an in situ redox reaction between cPAN and potassium permanganate. The fabricated cPAN-MnO2 membrane exhibited instantaneous reduction property towards MB in DMSO during a gravity-driven continuous filtration process. Interestingly, MB reduction was initiated by a typical Fenton-like oxidization, where hydroxyl radicals were firstly generated from hydrogen peroxide catalyzed by MnO2 in DMSO. Then hydroxyl radicals attacked DMSO to further produce methyl radicals, which resulted in the reduction of MB. In addition, MB reduction process in DMSO was reversible. Our study provides a novel strategy for continuous redox of MB in polar organic solvent and might give new ideas for MB applications.