贵金属改性二氧化钛光催化去除饮用水中溴酸盐

发布时间：2018-12-23 11:08

【摘要】：为提高二氧化钛（TiO_2）光催化去除饮用水消毒副产物溴酸盐（BrO_3~-）的效率，本文围绕贵金属改性二氧化钛光催化去除溴酸盐开展了系统的研究，以期进一步提高二氧化钛光催化去除溴酸盐速率，推动光催化还原法在饮用水水处理领域的应用。 首先，开展了贵金属改性二氧化钛光催化剂筛选的研究。采用等体积浸渍法制备了各贵金属（包括铂Pt、钯Pd、钌Ru、铑Rh、铱Ir、金Au和银Ag）改性二氧化钛，通过UV-Vis漫反射和XPS表征了催化剂的光吸收性能及表面元素组成，考察了紫外光下其光催化去除溴酸盐活性。结果表明，Pt和高负载量的Ag有效提高了TiO_2光催化去除BrO_3~-的活性，Pd、Ru、Au、Ir、Rh和低负载量的Ag抑制了TiO_2光催化去除BrO_3~-活性。 其次，开展了紫外光下优选的Pt/TiO_2光催化剂光催化去除溴酸盐的研究。考察了各影响因素，包括负载量、煅烧温度、pH、溶解氧、有机物乙醇和可见光等，对Pt/TiO_2光催化去除溴酸盐的影响，并研究了Pt/TiO_2光催化去除溴酸盐动力学。结果表明，Pt/TiO_2最优负载量为0.01%，最优煅烧温度为400℃；低pH极大地促进了Pt/TiO_2光催化还原BrO_3~-；溶解氧严重抑制了Pt/TiO_2光催化去除BrO_3~-活性；有机物乙醇轻微抑制了Pt/TiO_2光催化去除BrO_3~-活性；1.0%Pt/TiO_2具有较好的可见光光催化去除溴酸盐活性。Pt/TiO_2光催化去除BrO_3~-表现为一级反应动力学，动力学常数K为0.03min~(-1)。 然后，开展了紫外光下优选的Ag/TiO_2光催化剂光催化去除溴酸盐的研究。考察了各影响因素，包括负载量、煅烧温度、pH、溶解氧、有机物乙醇和可见光等，对Ag/TiO_2光催化去除溴酸盐的影响，并研究了Ag/TiO_2光催化去除溴酸盐动力学。结果表明，Ag/TiO_2最优负载量为6.0%，最优煅烧温度为400℃；随pH的增加，Ag/TiO_2催化去除BrO_3~-活性先增加后降低，最优pH为7.2；向溶液中通入溶解氧和N2都抑制了Ag/TiO_2光催化去除BrO_3~-；有机物乙醇也抑制了Ag/TiO_2光催化去除BrO_3~-活性；6.0%Ag/TiO_2具有很好的可见光光催化去除溴酸盐活性。Ag/TiO_2光催化去除BrO_3~-表现为一级反应动力学，动力学常数K为0.01min~(-1)。 最后，开展了可见光下，Ag/TiO_2光催化去除溴酸盐的研究。考察了各影响因素，，包括负载量、煅烧温度、pH和有机物乙醇等，对Ag/TiO_2可见光光催化去除溴酸盐的影响。结果表明，随Ag负载量的增加，Ag/TiO_2光催化去除溴酸盐先增加后趋稳再降低，最优Ag负载量为6%；最佳煅烧温度为300℃；随pH的增加，Ag/TiO_2可见光光催化还原BrO_3~-活性先增加后降低，最优pH为7.2；有机物乙醇抑制了Ag/TiO_2可见光光催化去除BrO_3~-活性。
[Abstract]:In order to improve the efficiency of photocatalytic removal of bromate (BrO_3~-) from drinking water by titanium dioxide (TiO_2), a systematic study on the photocatalytic removal of bromate by noble metal modified titania was carried out in this paper. In order to further improve the titanium dioxide photocatalytic removal rate of bromate, promote the application of photocatalytic reduction in drinking water treatment. Firstly, the selection of noble metal modified titanium dioxide photocatalyst was studied. Titanium dioxide modified by platinum Pt, palladium, Pd, ruthenium, Rh, iridium, Ir, Au and silver Ag was prepared by isovolumetric impregnation method. The photoabsorption properties and surface element composition of the catalysts were characterized by UV-Vis diffuse reflection and XPS. The photocatalytic activity of bromate removal under ultraviolet light was investigated. The results showed that Pt and Ag with high loading effectively increased the photocatalytic activity of TiO_2 for BrO_3~- removal, and Pd,Ru,Au,Ir,Rh and low load Ag inhibited the photocatalytic removal of BrO_3~- from TiO_2. Secondly, the photocatalytic removal of bromate with Pt/TiO_2 photocatalyst was studied. The effects of various factors, including loading amount, calcination temperature, pH, dissolved oxygen, organic ethanol and visible light, on the removal of bromate by Pt/TiO_2 were investigated. The kinetics of Pt/TiO_2 photocatalytic removal of bromate was also studied. The results show that the optimum loading amount of Pt/TiO_2 is 0.01 and the optimal calcination temperature is 400 鈩

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