Fenton氧化处理焦化废水的工艺优化及有机物降解机制

Process optimization and degradation mechanism of organic matter in Fenton oxidation treatment of coking wastewater

采用Fenton反应对焦化废水中污染物进行氧化处理,考察时间、pH值、H_(2)O_(2)/COD质量比和Fe^(2+)/H_(2)O_(2)物质的量比对于焦化废水的降解效果,并采用响应曲面法进行参数优化,同时探究反应中有机物组分的变化规律.结果表明:Fenton氧化对于焦化废水有较好的处理效果,当pH=3.19、m(H_(2)O_(2)/COD)为1.72、n(Fe^(2+)/H_(2)O_(2))为0.74、反应时间为40min的条件下,COD的去除率达到72.69%.处理后废水的可生化性(B/C)比由0.24提高至0.32.对反应前后焦化废水中有机物进行分析,原水中共有21种有机物,种类复杂多为大分子物质,Fenton出水中有机物种类显著减少为14种.其中,含氮类有机物被完全降解,部分芳香族化合物中的苯环裂解,大部分长链有机物断裂为短链有机物,整体分子量减小.

In this study,Fenton reaction was used to oxidize pollutants in coking wastewater,and the degradation effects of time,pH,H_(2)O_(2)/COD mass ratio and Fe^(2+)/H_(2)O_(2) molar ratio on coking wastewater were investigated.The response surface method(RSM)was used to optimize parameters,and the change rule of organic compounds in the reaction was explored.The results show that Fenton oxidation has a good treatment effect on coking wastewater.Under the conditions of pH=3.19,m(H_(2)O_(2)/COD)1.72,n(Fe^(2+)/H_(2)O_(2))0.74 and reaction time 40min,the COD removal rate was 72.69%.The B/C ratio of treated wastewater increased from 0.24 to 0.32.According to the analysis of organic matter in coking wastewater before and after the reaction,there were 21 kinds of organic matter in raw water,most of which were macromolecular substances with complex types,while the number of organic matter in Fenton effluent was significantly reduced to 14.Among them,nitrogen-containing organic matter was completely degraded,some aromatic compounds in the benzene ring cracked,most of the long chain organic matter was broken into short chain organic matter,and the overall molecular weight decreased.