Preparation of Bismuth Tungstate/Preoxidized Acrylonitrile/Acrylic Acid Copolymer Composite Nanofiber Membrane and Its Photocatalytic Properties

Background: In this patent article, a novel bismuth tungstate/preoxidized acrylonitrile/ acrylic acid (AN/AA) copolymer composite nanofiber membrane was prepared, which was used as the visible light catalyst. Methods: AN/AA copolymer was synthesized, which was electrospun with bismuth nitrate and sodium tungstate to prepare the composite nanofiber. Then the composite nanofiber was preoxidized to prepare the bismuth tungstate/preoxidized AN/AA composite nanofiber membrane containing adsorption moiety and photocatalytic active moiety. Results: The photocatalytic activity of bismuth tungstate/preoxidized AN/AA composite nanofiber membrane with different preoxidized temperature, heating rate, and holding time by catalytic degradation of methylene blue was investigated. The optimal preoxidized conditions were as follows: the preoxidized temperature was heated to 200 °C with the heating rate of 1°C/min and the holding time at this temperature was 12 h. The chemical structure and morphology of the composite nanofiber membrane were characterized by FTIR, XRD, and SEM. Conclusion: The bismuth tungstate/preoxidized AN/AA composite nanofiber membrane obtained good photocatalytic properties and reusability under visible light. The degradation rate of methylene blue by this visible light catalyst could reach 90.24% for 4.5 h, and the degradation rate remained 81.53% for 4.5 h after 5 reuses.