TiO2-PW9复合催化剂光催化降解游离氰

采用水热法制备了二氧化钛(TiO_2)与三缺位磷钨酸钠(Na_8Hβ-A-PW_9O_(34)]·24H_2O)共价结合形成的TiO_2-PW_9复合催化剂,并对其光催化降解游离氰(CN~-)的效果进行了研究.NMR和XPS等表征结果证明,Na_8Hβ-A-PW_9O_(34)]·24H_2O(简写为Na-PW_9)已成功负载于TiO_2上.光电化学表征结果表明,Na-PW_9的引入可有效提高TiO_2的界面电荷转移.光催化实验结果表明,与单独TiO_2相比,TiO_2-PW_9的光催化活性有明显提高.同时,探究了初始CN~-浓度和催化剂投加量对CN~-去除的影响.结果表明,当初始CN~-浓度为0.3 mmol·L~(-1)、催化剂投加量为1 g·L~(-1)时,复合催化剂的光催化活性最佳,反应150 min后,CN~-的去除率达到81%.CN~-的氧化产物分析结果表明,氰酸根(CNO~-)是CN~-氧化的唯一产物.自由基淬灭实验和电子自旋共振(ESR)波谱分析结果表明,~1O_2是反应体系中的主要活性氧物种.本实验可为多功能催化材料的开发及其在含氰废水污染控制领域的应用提供参考.

Photocatalytic degradation of free cyanide by TiO2-PW9 composite catalyst

TiO₂-PW₉ composite catalyst formed by covalent combination of TiO₂ and Na-PW₉ was prepared through a facile hydrothermal method and its photocatalytic CN^- degradation was investigated. The characterization such as NMR and XPS results confirmed the presence of Na-PW₉ on the TiO₂ surface. The photoelectrochemical characterization confirmed that the introduction of Na-PW₉ could effectively improve the interfacial charge transfer. Compared with bare TiO₂, the TiO₂-PW₉ composite shows an enhanced photocatalytic activity for CN^- degradation. The removal efficiency of CN^- can reach up to 81% after 150 minutes under the optimal condition of initial CN^- concentration of 0.3 mmol·L^-1 and catalyst dosage of 1 g·L^-1. Product analysis results indicated that the CNO^- was the only product. Radical quenching experiment and ESR analysis results demonstrate that ¹O₂ is the main reactive oxygen species in the reaction system. This work provides a reference for the design of multifunctional catalytic materials with applications in treatment of cyanide-containing wastewater.