零价铁降解4-氯硝基苯动力学研究

实验采用无氧条件下不同浓度零价铁降解硝基芳香烃代表物4-氯硝基苯,研究4-氯硝基苯的降解速率及各产物的反应速率.根据化学反应计量学,通过准一级动力学方程对实验结果进行拟合,得到生成各产物反应速率,并利用穆斯堡尔技术检测零价铁的产物.结果表明,4-氯硝基苯的还原转化速率与零价铁浓度有关,中间产物4-氯亚硝基苯和4-氯苯基羟胺的生成和转化速率可通过拟合各反应速率得到.当零价铁浓度为1.04 g.L-1时4-氯硝基苯反应速率最快,反应速率常数为0.189min-1.反应过程中生成的亚铁离子在反应初期吸附在零价铁表面,各物质的生成和还原速率取决于零价铁表面的活性位点和各物质与零价铁之间的质量传递.

Kinetic Study of 4-Chloronitrobenzene Degradation by Zero-Valent Iron

4-chloronitrobenzene as a representative material of nitroaromatic compounds was used in this study to investigate the degradation reaction rate and products by different concentrations of zero-valent iron (ZVI) under anoxic condition. According to stoichiometry, different reaction rates of products were obtained by fitting the experimental data. Products of ZVI were measured by Mössbauer technique. The results show that reduction of 4-chloronitrobenzene corresponds to the concentration of ZVI. The production and transformation rates of intermediate products, 4-chloronitrosobenzene and 4-chloro phenyl hydroxylamine, can be achieved. The 4-chloronitrobenzene reduction reaction is the fastest when the ZVI concentration is 1.04 g·L^-1. The reaction rate constant is 0.189 min^-1. Ferrous iron ions generated during reaction are sorbed on the ZVI surfaces in the early age of the reaction. Formation and reduction reaction rates of different products depend on the reactive sites of ZVI and the mass transfer between each other.