CdSe QDs/TiO_(2)复合催化剂对氨氮废水的光降解性能研究

Investigation on the Photodegradation Performance of CdSe QDs/TiO_(2) Composite Photocatalyst for Ammonia Nitrogen Wastewater

针对氨氮废水的有效处理,文章以水相合成法制备CdSe量子点溶液,通过巯基丙酸将CdSe量子点负载在P25载体上,制备了CdSe QDs/TiO_(2)复合光催化剂。通过TEM、XRD、XPS和EIS等表征测试结果,分析证实了复合催化剂的结构和可见光吸收能力。在弱碱条件下,通过考察助催化剂、CdSe QDs负载量、催化剂投加量和氨氮初始浓度等因素,评价了该体系在多因素影响下的光催化降解效率。结果表明,氨氮初始浓度为50 mg/L,pH=9,CdSe QDs负载量为1%,催化剂添加量为0.05 g,K_(2)S_(2)O_(8)添加量为0.054 g(2 mmol/L)时,光催化降解效果最佳,氨氮降解率达到81.79%。通过活性物质捕获实验研究了CdSe QDs/TiO_(2)光催化降解氨氮废水的机理,证实了体系中主要氧化活性物质为·O_(2)^(-)。

Aiming at the effective treatment of ammonia nitrogen wastewater,CdSe quantum dot solution was prepared by aqueous synthesis method.And the CdSe QDs/TiO_(2)composite photocatalyst was prepared with P25 as a carrier linked by difunctional mercaptopropionic acid.The results of TEM,XRD,XPS and EIS confirmed the structure and visible light absorption capacity of the composite photocatalyst.Under the condition of weak base,the photocatalytic degradation efficiency of the system under the influence of multiple factors was evaluated by investigating the factors such as cocatalyst,CdSe QDs loading,catalyst dosage and initial concentration of ammonia nitrogen.The results showed that the initial concentration of ammonia nitrogen in reaction system was set to 50 mg/L,and the pH was adjusted to 9,0.05 g of the composite catalyst with 1%CdSe quantum dot loading and 0.054 g K_(2)S_(2)O_(8)to the reaction system,the degradation effect was the best.The removal rate of ammonia nitrogen under visible light reached 81.79%.The mechanism of photocatalytic degradation of ammonia nitrogen wastewater by CdSe QDs/TiO_(2)was studied through active substance capture experiment,and it was confirmed that the main oxidation active substance in the system was·O_(2)^(-).