催化臭氧氧化过程中溴酸盐的生成机制研究

Study on Bromate Formation of Catalytic Ozonation Process

以黄河下游某水厂滤后水为目标物,选择了9种催化剂,在间歇反应装置中研究了单独臭氧和催化臭氧氧化过程中溴酸盐(BrO 3-)的生成情况,结果表明,在催化臭氧氧化过程中,NiO、CuO、Fe3O4、Al2O3加入使BrO 3-质量分数分别降低34.0%、32.8%、29.2%、20.8%.选取Fe3 O4作为催化剂研究催化臭氧氧化滤后水过程中BrO 3-生成情况.结果表明,反应过程中的Rct值随反应时间的延长而降低,整个反应过程中Rct值在10-8～10-6之间.单独臭氧氧化滤后水时,BrO 3-的生成主要是直接-间接途径和间接-直接途径共同作用的结果;催化臭氧氧化生成BrO 3-的主要途径是间接-直接途径.此外,催化臭氧氧化过程中有效提高了有机物的降解,UV254的降解率提高到60.7%.研究表明,催化臭氧氧化能有效抑制BrO 3-的生成,又能提高对有机物的去除效果.

In a batch reactor,the BrO-3 formation was investigated in the ozonation and catalytic ozonation of Br——containing Yellow river water,using the different heterogeneous catalysts.The results showed that BrO-3 minimization was achieved in the catalytic ozonation with NiO,CuO,Fe3O4 and Al2O3 as catalysts and the percent reductions of BrO-3 were 34.0%,32.8%,29.2% and 20.8% respectively.In the reaction Rct,the ratio of concentration of ·OH to O3,decreased with the reaction time,and the range of Rct was from 10-8 to 10-6.In the ozonation process,one of the main reaction pathways of BrO-3 formation was the combination oxidation of Br-by ·OH and then O3,another was the combination oxidation of Br-by O3 and then ·OH.In the catalytic ozonation with Fe3O4 catalyst,the main pathway was the combination oxidation by ·OH and then O3.Moreover,about 60.7% removal for UV254 was obtained after 20 min in the catalytic ozonation reaction.In our study,it was found that the catalytic ozonation process can effectively minimize the formation of BrO-3 and also oxidize organic compounds.