纳米铁还原高浓度硝基苯的实验

摘要

采用液相还原法制备纳米铁粒子,粒径约为50 nm,主要成分为a-Fe.实验研究了纳米铁还原高浓度硝基苯的效果及反应动力学.结果表明:自制的纳米铁具有很高的活性,短时间内能将高浓度硝基苯彻底还原,效果远优于普通铁粉.当摩尔比满足n纳米铁∶n硝基苯=4∶1时,纳米铁还原硝基苯属于一级反应动力学,反应速率常数和半衰期分别为0.159 3 h-1和4.351 2h.整个实验过程中,p(DO)在0.5 mg/L以下,pH值约为9.0,体系呈弱碱性的厌氧环境,有利于厌氧微生物的生长.纳米铁反应后的产物为Fe6(OH)12 C03和MgFe3O4,且以 Fe6 (OH) 12CO3为主.纳米铁反应后较以前比粒径变化不大,分散性较好,但表面被严重腐蚀.%The nanoscale a-Fe particles with size of about 50 nm was prepared with liquid phase reducing method, and the degradation kinetics in the treatment of high concentration nitrobenzene were studied. This kind of Fe particles showed higher activity, removed nitrobenzene(NB) completely in a short time. Under the condition of a-Fe/NB 4, the reduction of nitrobenzene by nanoscale zero-valent iron( NZVI) can be described as first-order kinetics, reaction rate constant and half-life were 0. 159 3 h-1 and 4. 351 2 h. p( DO) was maintained under 0.5 mg/L while pH was about 9.0 in the whole progress, which created a favorable environment for the growth of anaerobic microbes. The reaction products were mainly Fe6(OH)12CO3 and MgFe3O4, mostly the Fe6(OH)12CO3, the size of NZVI changed little while the disperation was better after reaction. However, the surface of Fe was corroded seriously.