Photocatalytic reduction of hexavalent chromium in wastewater has been widely investigated as an attractive treatment method. In this work, we reported an efficient method for photocatalytic reduction of Cr（VI） over...Photocatalytic reduction of hexavalent chromium in wastewater has been widely investigated as an attractive treatment method. In this work, we reported an efficient method for photocatalytic reduction of Cr（VI） over transparent polyvinyl alcohol/titanium dioxide （PVA/TiO2） nanocomposite films under sunlight irradiation. The trans- parent PVA/TiO2 nanocomposite films were prepared by a simple hydrothermal method combined with a solution casting process. The results revealed that the anatase TiO2 nanoparticles with size less than 10 nm were in-situ generated in PVA matrix, which endowed the films with high trans- parency. Photocatalytic reduction of Cr（VI） over PVA/TiO2 nanocomposite films exhibited superior visible light pho- tocatalytic activity. Mechanism investigation demonstrated that the PVA acted not only as a transparent support for TiO2 nanoparticles, but also as holes scavengers simultaneously to improve the separation of photogenerated holes and elec- trons. Meanwhile, the transparent PVA/TiO2 nanocomposite films displayed remarkable stability and excellent recyclabil- ity during multicycle Cr（VI） photoreduction. Furthermore, the PVA/TiO2 nanocomposite films showed selective adsorp- tion ability for Cr（III）, and thus totally removal of Cr（VI） was achieved after photoreduction process.展开更多
基金supported by the Joint Program of Beijing Natural Science Foundation and Beijing Academy of Science and Technology (L140005)the National Natural Science Foundation of China (51203094)
文摘Photocatalytic reduction of hexavalent chromium in wastewater has been widely investigated as an attractive treatment method. In this work, we reported an efficient method for photocatalytic reduction of Cr（VI） over transparent polyvinyl alcohol/titanium dioxide （PVA/TiO2） nanocomposite films under sunlight irradiation. The trans- parent PVA/TiO2 nanocomposite films were prepared by a simple hydrothermal method combined with a solution casting process. The results revealed that the anatase TiO2 nanoparticles with size less than 10 nm were in-situ generated in PVA matrix, which endowed the films with high trans- parency. Photocatalytic reduction of Cr（VI） over PVA/TiO2 nanocomposite films exhibited superior visible light pho- tocatalytic activity. Mechanism investigation demonstrated that the PVA acted not only as a transparent support for TiO2 nanoparticles, but also as holes scavengers simultaneously to improve the separation of photogenerated holes and elec- trons. Meanwhile, the transparent PVA/TiO2 nanocomposite films displayed remarkable stability and excellent recyclabil- ity during multicycle Cr（VI） photoreduction. Furthermore, the PVA/TiO2 nanocomposite films showed selective adsorp- tion ability for Cr（III）, and thus totally removal of Cr（VI） was achieved after photoreduction process.
