水处理光电催化反应器内部结构优化布设机理探讨

光电催化(PEC)反应器内部结构的优化布设对水中污染物的降解效率至关重要.本文采用氧化还原法制备了一种蓝色TiO_2纳米管阵列电极板,探究了PEC反应器内各布设因素对亚甲基蓝(MB)降解效果的影响.结果表明,阳极板与光源中心距离的减小、阳极板旋转角度的减小及阳极板数量的增加均会导致MB降解速率的加快.进一步分析表明,各布设因素对MB的降解影响均可归因为紫外(UV)辐照强度.MB的PEC降解速率与阳极板表面UV辐照强度呈线性正相关,其线性拟合公式的斜率(0.00219)和截距(0.0049)分别反映了UV光子应用于阳极催化氧化和直接光降解MB的相对效果,揭示了各反应对MB降解速率的贡献.此外,不同内径(64、72和80 mm)的PEC反应器对比结果表明,反应器内径越小,MB降解速率越快,但内径为80 mm的反应器降解MB的单位电能消耗(E_(EO))最低(17.24 kWh·m~(-3)·order~(-1)).最后,量化分析了不同内径反应器中阳极催化氧化和直接光降解对MB降解速率的贡献,为PEC反应器的优化设计提供了重要参考.

Mechanism study on the optimal layout of the internal structure of a photoelectrocatalytic reactor for water treatment

The optimal layout of the internal structure of a photoelectrocatalytic (PEC) reactor is essential for the degradation of pollutants in water. In this work, blue TiO₂ nanotube arrays electrode plates were prepared by an oxidation-reduction method. The influences of various layout factors of a PEC reactor on methylene blue (MB) degradation were investigated. Experimental results indicate that the MB degradation rate increased with the decreasing distance between the anode plate and the center of the light source, the decreasing rotation angle of the anode plate, and the increasing anode plate number. Further analysis results indicate that the influence of each layout factor on the MB degradation could all be ascribed to the ultraviolet (UV) fluence rate. The MB degradation rate shows a positively linear correlation with the UV fluence rate. The slope (0.00219) and intercept (0.0049) of the linear regression equation represent the relative efficiencies of UV photons used by anode catalytic oxidation and direct photolysis on MB degradation, respectively, and clarified the contribution of each reaction to the MB degradation rate. Moreover, comparison results of the PEC reactors with different inner diameters (64, 72 and 80 mm) show that a smaller inner diameter led to a faster MB degradation rate, but the PEC reactor with an inner diameter of 80 mm had the lowest consumption of electrical energy per order (E_EO) for MB degradation (17.24 kWh·m^-3·order^-1). Finally, the contributions of anode catalytic oxidation and direct photolysis to the MB degradation rate in PEC reactors with various inner diameters were quantitatively analyzed, which provides important reference for the optimal design of a PEC reactor.