Co3O4/BiVO4复合阳极活化过一硫酸盐强化光电催化降解双酚A

采用静电纺丝法制备了Co_3O_4/BiVO_4复合薄膜电极,并以之为光阳极,在过一硫酸盐(PMS)辅助作用下开展了光电催化降解双酚A研究.结果表明,PMS在可见光下可显著强化Co_3O_4/BiVO_4复合阳极光电催化降解双酚A,在0.25 V外加偏压以及可见光照射下,当加入2 mmol·L-1PMS时,双酚A在2 h内的降解效率为96%.降解动力学常数为0.471 4 min-1.系统研究了PMS初始浓度、外加偏压对双酚A降解性能的影响.结果发现,双酚A在较低的PMS投加量和较低的外加偏压(0.25 V)下即可有效降解.采用电子自旋共振波谱仪鉴定体系的主要活性自由基为SO·-4和·OH.并进一步通过淬灭实验结果证明空穴、SO·-4和·OH起主要氧化作用.光电反应后的体系中未检测到金属离子溶出,可避免二次污染.

Enhancement of Photoelectrocatalytic Degradation of Bisphenol A with Peroxymonosulfate Activated by a Co3O4/BiVO4 Composite Photoanode

A nanostructured Co₃O₄/BiVO₄ composite photoanode was synthesized using a facile electrospinning method and applied to photoelectrochemical (PEC) degradation of bisphenol A (BPA) with the assistance of peroxymonosulfate (PMS). Results show that PMS obviously enhanced the photoelectrocatalytic degradation of BPA by the Co₃O₄/BiVO₄ composite photoanode. When at 0.25 V bias potential and visible light irradiation, with 2 mmol·L^-1 PMS addition, 96% of BPA was removed within 2 h, and the corresponding kinetic constant was 0.4714 min^-1. The effects of initial PMS concentration and bias potential on the BPA degradation were studied. Results show that BPA could be efficiently degraded at lower PMS concentrations and lower bias potentials. SO₄^·- and·OH were identified as the primary free radicals using an electron spin resonance spectrometer. Free radical quenching experiments were carried out, and the photogenerated hole, SO₄^·-, and·OH proved to be responsible for the BPA oxidation. There was no metal ion leaching detected in the solution after the reactions, which means the secondary pollution could be avoided.