双极液膜法可见光光催化降解染料废水

采用溶胶-凝胶法制备了Bi2O3-TiO2/Ti膜电极,X射线衍射(XRD)、X射线光电子能谱(XPS)、紫外-可见漫反射(DRS)和光电性能测试进行了表征,结果表明,Bi元素掺杂进入了TiO2催化剂,拓展了催化剂的光响应波长,使其在可见光下有较明显的光电响应.将Bi2O3-TiO2/Ti光阳极与Cu阴极组装成双极液膜反应器,在可见光下光催化处理活性艳红X-3B,得出当初始pH值为2.52,废水流量为80mL/min时,处理20mg/L活性艳红X-3B 150min,脱色率可达88%.双极液膜法可见光光催化的初步机理考察表明,光生电子自发由Bi2O3-TiO2表面转移到Cu电极表面,并在Cu电极表面直接还原染料,或与其表面液膜中的溶解氧反应生成H2O2,进而参与染料的氧化,由此可实现Bi2O3-TiO2/Ti的直接氧化和Cu阴极的直接还原和间接氧化的双极双效效果.

Dual electrodes photocatalytic degradation of dye wastewater under visible light irradiation

Bi2O3-TiO2/Ti thin film electrodes have been prepared by sol-gel method. The characterization of X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS) and photoelectric performance test demonstrates Bi was successfully doped into TiO2 photocatalyst and it existed in the form of Bi2O3. Compared to pure TiO2 photocatalyst, light response wavelength of Bi2O3 doped TiO2 photocatalyst has been extended and it has obvious photoelectric response in visible region. The dual slant-placed electrodes thin-film reactor was assembled, using the prepared Bi2O3-TiO2/Ti as photoanode and Cu as cathode, and successfully used to photocatalytic (PC) treat Reactive Brilliant Red X-3B (RBR) under visible light irradiation. The main influence factors of the PC reaction were investigated. The decolourization efficiency of 20mg/L RBR reached 88% for 150min treatment under the conditions of initial pH 2.52 and circulating flux 80mL/min. The preliminary mechanism of the dual electrodes thin-film PC was investigated. The results demonstrate the photogenerated electrons can be spontaneously transferred from the surface of the Bi2O3-TiO2/Ti photoanode to the surface of Cu cathode. On the surface of Cu cathode, electrons can reduce RBR directly, or react with dissolved oxygen to form H2O2, which can further participate in the oxidation of the RBR. In this way, dual electrodes degradation can be obtained by the direct oxidation on Bi2O3-TiO2/Ti photoanode and indirect oxidation and direct induction on Cu cathode.