CeO_(2)/TiO_(2)-Ag_(3)PO_(4)复合催化剂去除废水中LAS的性能研究

Study on the performance of CeO_(2)/TiO_(2)-Ag_(3)PO_(4) composite catalyst to remove LAS in wastewater

采用化学共沉淀法制备了CeO_(2)掺杂不同含量的TiO_(2)-Ag_(3)PO_(4)复合光催化剂(CeO_(2)/TiO_(2)-Ag_(3)PO_(4)),考察了该催化剂对LAS废水中有机物的光催化降解性能。结果表明:CeO_(2)掺杂比为0.5%的三元复合光催化剂,对溶液中甲基蓝(MB)和十二烷基苯磺酸钠(SDBS)均有最佳的降解效率,催化剂最佳投加量为1.00~1.10g/L,紫外光照射30min,在不调节溶液pH条件下,对SDBS的光催化降解效率可高达99.86%;同等反应条件下,SDBS的去除率随着溶液初始浓度的升高而降低,通过动力学拟合分析,发现该催化剂对SDBS的催化降解反应遵循二级动力学特性。催化剂的光催化活性在酸性溶液条件下明显要优于中性和碱性条件;重复使用5次,催化剂降解SDBS仍表现出较好的循环稳定性和高效催化性;光催化机理实验表明紫外光下复合光催化剂降解SDBS的过程中主要的活性物种是超氧自由基。因此,该方法制备的负载型催化剂具有催化活性高、性能相对稳定、可重复循环使用等优点,对LAS废水和印染废水后处理环节均具有潜在的应用前景。

The TiO_(2)-Ag_(3)PO_(4)composite photocatalyst(CeO_(2)/TiO_(2)-Ag_(3)PO_(4)) doped with rare earth CeO_(2)was prepared by chemical co-precipitation method, and the photocatalytic degradation performance of the catalyst on the organic matter in LAS wastewater was further investigated.The experimental results showed that the ternary composite photocatalyst with a CeO_(2)doping ratio of 0.5 wt% had the best degradation efficiency for MB and SDBS in the solution.The optimal dosage of the catalyst was 1.00~1.10 g/L and the photocatalytic degradation efficiency of SDBS was as high as 99.86% in the ultraviolet light for 30 min under the condition of not adjusting the pH value of the solution.Under the same reaction conditions, the removal rate of SDBS decreased with the increase of the initial concentration of the solution.Through kinetic fitting analysis, it was found that the catalytic degradation reaction of the catalyst to SDBS followed the second-order kinetic characteristics.The photocatalytic activity of the catalyst in acidic solution was obviously better than that in neutral and alkaline conditions.The catalyst degrades SDBS still showed good cycle stability and high-efficiency catalytic performance after repeated use for 5 times.Photocatalytic mechanism experiments showed that the main active species, in the degradation of SDBS by the composite photocatalyst in ultraviolet light, is superoxide radicals.Therefore, the supported catalyst prepared by the method had the advantages of high catalytic activity, relatively stable performance, recyclable use, etc.,and possessed potential application prospects for the post-treatment links of LAS wastewater and printing and dyeing wastewater.