Integrated α-MnO2 nanowires PVDF catalytic membranes for efficient purification of dye wastewater with high permeability

Abstract

Catalytic membranes have been studied and reported widely, but ideal catalytic membranes with high rejection ratio and high permeability simultaneously are still a challenge to develop. Herein, integrated α-MnO2 nanowires polyvinylidene fluoride (PVDF) catalytic membranes were fabricated by a vacuum filtration method. Based on the intercalation structures of GO formed by α-MnO2 nanowires and the spatial stacking of nanowires, filter channels with high water flux were constructed. While CS displayed as anchor point to fix α-MnO2 nanowires and also endow the membrane surface with electro-positivity. Then, a sequence of catalytic membranes with different content of α-MnO2 were prepared, and detailed characterizations of structure were taken out. Finally, all of the membranes displayed excellent stability in harsh conditions (pH values from 3 to 11), and M-5 with the most content of α-MnO2 displayed the best separation ability, for which the rejection ratio reached 99.26 % along with a high permeability about 923.72 L·m−2·h−1·Bar−1, when it was used to separate methyl blue (MBE) wastewater. In addition, M-5 also displayed excellent reusability, such as the rejection ratio still maintained above 92.62 % after 9th cycles and reduced to 86.74 % after 10th cycle, while the permeability still remained 612.09 L·m−2·h−1·Bar−1 after the 10th cycle. Therefore, this work developed an outstanding catalytic membrane, which displayed good application prospect for treatment of dye wastewater.