二氧化钛固定膜光催化氧化降解双酚A特性研究

Photocatalytic Degradation Characteristics of Bisphenol A with Immobilized Catalyst

目的探讨负载于玻璃纤维网上纳米二氧化钛(TiO2)催化剂对双酚A(BPA)的降解特性。方法以小型固定膜光催化反应装置研究不同光源下[黑光灯、冷阴极低压汞灯(UV254)]光解作用和BPA初始浓度(0.98～6.23mg/L)对BPA降解的影响,以及BPA在不同光源下的矿化过程及其中间产物的差别。结果在较低浓度范围内(0.98～6.23mg/L),BPA的降解呈表观一级反应,且表观反应速率常数在不同光源下均随初始浓度增大而减小。在黑光灯下,光解作用影响不明显;而在冷阴极低压汞灯下,光解作用影响显著,BPA降解是光解作用和光催化作用共同作用的结果。BPA光催化矿化过程也存在很大差异,在黑光灯下,BPA的中间产物包括对苯醌、对苯二酚、对羟基苯甲酸甲酯、对羟基苯乙酮、1-对羟基苯-1-丙酮和1-对羟基苯乙烯醇;在冷阴极低压汞灯下,BPA的中间产物包括3-羟基-3-丁烯酸、对羟基苯甲醛、对羟基苯乙酮、2-乙酰-5,8二羟基-3-甲氧基-1,4-萘醌和3,4-二(4-羟苯基)己烷。结论光源对BPA光催化矿化过程存在明显影响,这是由BPA分子结构中存在两个苯环结构决定的。

Objective This study was carried out to reveal the photoeatalytic degradation characteristics of Bisphenol A, a representative endocrine disruptor, with immobilized nanometer TiO2 catalyst supported on fiberglass net. Methods The effects of photolysis under black light lamp and cold cathode low-pressure mercury lamp, and initial concentration （0.98-6.23 mg/L） on the degradation of bisphenol A （BPA） was explored by photoreactor in laboratory. Photocatalytie mineralization and intermediates under different irradiations was also investigated. Results It was found that the reaction kinetics was first order with respect to BPA concentration, and the apparent kinetic constants decreased with the increase of initial concentration. Photodecomposition of BPA under black light lamp irradiation was caused by not photolysis but photoeatalysis,while that under cold cathode low-pressure mercury lamp was caused by the synergistic effect of photolysis as well as photocatalysis. Further studies showed that photocatalytie mineralization of BPA differed greatly under those different irradiations.1,4-benzoquinone, p-dihydroxybenzene, methyl p- hydroxybenzoate, D-hydroxyaeetophehone, 1-（4-hydroxyphenyl）-1-propanone, 1-（4-hydroxyphenyl）-vinyl alcohol were identified as intermediates under black light lamp, and 3-hydroxyl-3-crotonic acid, 4-hydroxybenzaldehyde,D-hydroxyacetophehone,2-acetyl- 3-methoxyl-5,8-dihydroxy-1,4-naphthoquinone, 3,4-di-（4-hydroxyphenyl）hexane were found under cold cathode low-pressure mercury lamp. Conclusion The differences of photoeatalytie mineralization under different illumination are attributed to the molecule structure with two benzene-rings.