自掺杂铋基光催化剂光催化氧化及其单线态氧直接氧化协同降解PPCPs

常规生物和化学法难以处置布洛芬和双氯芬酸等难降解PPCPs。针对这些PPCPs的分子结构特点，本项目拟原位或异位制备自掺杂铋基光催化剂，改善其可见光响应能力，增强其光催化氧化能力；采用酸解、离子交换等改性方法，增强PPCPs与铋基催化剂之间的相互作用，包括催化剂表面氧空位与污染物分子中氧的作用、铋元素与污染物分子中氧和氮元素的配位作用、二维纳米片催化剂表面与污染物分子中苯环π体系之间的匹配作用，强化催化剂捕集目标污染物的能力；利用所得催化剂自身能产生单线态氧的特殊能力，构筑光催化氧化-直接氧化协同降解新体系。本项目将系统地研究PPCPs在铋基催化剂表面的吸附行为与其降解之间的相互关系、光催化氧化-直接氧化的协同效应，并采用GC-MS和HPLC-MS等手段分析降解过程中的中间产物种类及浓度变化规律，阐明PPCPs协同降解的反应机理，并针对医药废水，探讨新方法在处置PPCPs废水中的应用。

To efficiently degrade refractory PPCPs such as diclofenac and ibuprofen, a synergistic method is proposed by simultaneously using a visible light photocatalytic oxidation on self-doped Bi-containing photocatalysts and its inducing generation of singlet oxygen. Firstly, highly active self-doped Bi-containing photocatalysts are in-situ or ex-situ fabricated by acidic etching of sodium bismuthate or similar methods. The modified materials show much improved performance in the separation of photo-generated h+/e- pairs and then the photocatalytic ability. Then, the adsorption of PPCPs on the surface of bismuth based photocatalysts is enhanced by strengthening the multiple interactions between the target pollutants and the catalyst surface, including the insertion of an oxygen atom of -COO group in PPCPs molecular into oxygen vacancies, its bridge and configurations with bismuth on the catalyst surface, and the matching effect of a benzene-ring π system in PPCPs molecular with the out-surface of the bismuth based photocatalyst nanosheets. The modified Bi-containing photocatalysts also show a special function of generating singlet oxygen. Therefore, a novel system for the degradation of refractory PPCPs is developed by combining the singlet oxygen oxidation and photocatalytic oxidation. For this purpose, the correlation between PPCPs adsorption behavior and its degradation performance on the surface of bismuth based photocatalysts, and the synergistic effect between the singlet oxygen oxidation and visible light driven photocatalytic oxidation are systematically investigated. GC-MS and HPLC-MS are employed to track PPCPs degradation intermediates to clarify the degradation reaction process and mechanism of PPCPs. Finally, application of the novel method in the treatment of pharmaceutical wastewater is investigated.