微电解-催化氧化法处理甲苯二异氰酸酯硝化废水的研究

On treating the nitration sewage in the toluen discarnate production by micro-electrolysis an catalytic oxidation

在甲苯二异氰酸酯(TDI)生产废水中,硝化废水是最难处理的。针对硝化废水硝基苯类物质含量较高的特点,采用微电解-Fenton催化氧化组合工艺对冷却结晶后的废水进行处理,探讨各种反应条件和工艺参数对处理效果的影响。结果表明,微电解反应在pH值为1.5、m(Fe)∶m(C)=6∶1、反应时间为2 h时,对硝基苯类污染物去除率最高,达95.8%;后续处理采用Fenton催化氧化,当pH值为3.0、H2O2投加量为0.4%、反应时间为4 h时效果最好,CODCr去除率达95.1%。出水中各污染物指标均达到GB 8987—1996《污水综合排放标准》二级排放标准。

Aiming at studying the hightemperature feature of the ni trated sewage with plenty of nitrobenzene substances, this paper in tends to introduce a combined microelectrolysis and Fenton catalytic oxidation to address the crystallized nitrated sewage in a coolingoff state. For this purpose, we have discussed and analyzed the effects of different reaction conditions and the parameters concerned on the de tailed processing. The starting condition for our study is that when the parameters of microelectrolysis pH were 1.5, m（Fe） ： re（C） = 6： 1, the reaction time was 2 h, the removal effect of nitrobenzene and rel evant pollutants would reach the optimal point, with a 98.5 % of clearance. The production of toluene disocyanate tended to result in a great variety of industrial sewage with a lot of highly mixed proper ties. One of the most difficult properties is what we would like to pro pose, i.c. the nitrated water, in which it is possible to utilize the catalytic oxidant, the reagent Fenton in the subsequent procedures. Under the condition when the pH was 3.0, the rate of H202 should be 0.4%, the reaction time was 4 h, the clearance of the toxic sub stance we have measured tends to reach the optimal effects. In our examination, it was found that it was possible to remove CODcr, a major indicator in our experiment, to the highest extent, approxi mately 95.1%. After the treatment, all the pollutant indexes of the sewage proved to meet the second grade of the Integrated Sewage Dis charge Standard （GB 89781996）.