纳米Ni/Fe对水中硝基苯的催化还原特性

采用自制的纳米Ni/Fe对水中硝基苯进行催化还原处理。探讨了硝基苯的还原降解途径,考察了溶液pH、纳米Ni/Fe用量和Ni含量对还原效果的影响。结果表明,纳米Ni/Fe对水中硝基苯的去除是纳米Ni/Fe的吸附作用和还原作用的协同作用的结果,两者对硝基苯去除率的贡献分别为33.7%和66.3%。纳米Ni/Fe可将硝基苯还原为苯胺和中间产物亚硝基苯,亚硝基苯进一步被还原为最终产物苯胺。还原产物苯胺的生成率随溶液pH的升高而降低;随纳米Ni/Fe用量的增加而升高;Ni含量的适当增大有利于硝基苯还原为苯胺,但Ni含量过高时会导致苯胺生成率降低,适宜的Ni含量为1.85%。纳米Ni/Fe对硝基苯的催化还原过程遵循一级反应动力学规律,反应速率常数为0.0226 min-1。

Reduction of Nitrobenzene in Water by Nanoscale Ni/Fe Catalyst

Nanoscale Ni/Fe prepared in the laboratory was employed to reduce nitrobenzene in water.The reduction pathway of nitrobenzene was discussed.The effects of solution pH,Ni/Fe dosage and Ni content on reduction efficiencies of nitrobenzene were investigated.The results showed that the synergism of adsorption and reduction caused the removal of nitrobenzene.The contribution of adsorption and reduction to removal of nitrobenzene is 33.7% and 66.3%,respectively.Nitrobenzene can be reduced to aniline and the intermediate product nitrosobenzene,and nitrosobenzene can soon be reduced to the end product aniline.The yield of aniline decreases with the rise in pH and increases with the nanoscale Ni/Fe dosage.Increasing Ni content can be useful to reduce nitrobenzene to aniline,but superfluous Ni can decrease the yield of aniline.The optimum content of nickle is 1.85%.The reduction of nitrobenzene catalyzed by nanoscale Ni/Fe follows the first-order reaction kinetics.The reaction rate constant is 0.0226 min~(-1).