Fenton试剂液相催化氧化亚硝酸盐实验研究

Experimental Study on Catalytic Oxidation of Nitrite by Fenton Reagent in Liquid Phase

氧化法烟气脱硝技术在超低排放背景下很有应用前景,解决氧化吸收后亚硝酸盐的水体二次污染问题有助于推广该技术。该文验证了碱液吸收NO_2后,亚硝酸盐生成机制。通过对比试验选定最佳NO_2^-检测方法。考察了Fenton试剂液相催化氧化NO_2^-效果。探讨了pH值、H_2O_2浓度、Fe^(2+)浓度、微波敏化等因素对NO_2^-转化效率的影响。结果显示:Fenton试剂能够氧化亚硝酸盐,其中pH值、H_2O_2浓度、Fe^(2+)浓度,以及是否施加微波等条件,是NO_2^-转化效率的重要影响因素。当NO_2^-的浓度为452.51 mg/L时,加入0.03 mol/L H_2O_2和3 mmol/L的Fe^(2+)与之反应(无微波及活性炭敏化条件),可使NO_2^-转化效率高达94.88%;pH值、H_2O_2浓度、Fe^(2+)浓度等是NO_2^-转化效率的重要影响因素,最佳p H值是3,H_2O_2浓度、Fe^(2+)浓度的增加可提高NO_2^-转化效率;微波可提高NO_2^-转化效率,施加微波可将NO_2^-转化效率从58.88%提高至68.89%,且活性炭的添加可强化微波敏化效果,其中果壳基活性炭强化效果优于椰壳基活性炭。

Oxidation flue gas denitrification technology is very promising in the background of ultra-low emission and the solution of nitrite’s secondary pollution problem which is occurred after oxidation and absorption is helpful to popularize this technology.In this paper,the problem of nitrite’s formation after alkali absorption of NO2was verified at first,the best detection method of NO2-was selected,and the effects of pH value,H2O2concentration,Fe2+concentration,microwave sensitization and other factors on the conversion efficiency of NO2-were studied.The results indicated that Fenton’s reagent can oxidize nitrite,and the conversion efficiency of NO2-is 94.88%when NO2-concentration is 452.51 mg/L,H2O2concentration is 0.03mol/L,and Fe2+concentration is 3 mmol/L;p H,H2O2concentration and Fe2+concentration are the important factors which affect the conversion efficiency of NO2-,3 is the best pH value,and the increases of H2O2concentration and Fe2+concentration can raise the conversion efficiency of NO2-.Microwave can improve the conversion efficiency of NO2-which can increase the conversion efficiency of NO2-from 58.88%to 68.89%,the addition of activated carbon can enhance the effect of microwave sensitization,and the enhancing effect of fruit-shell activated carbon is better than coconut-based activated carbon.