纳米铁去除水中硝酸盐的动力学研究  

Kinetics of removing nitrate by nanoscale zero-valent iron

作　　者：廖娣劼[1] 杨琦[1] 尚海涛[1] 

机构地区：[1]中国地质大学(北京)水资源与环境学院,北京100083

出　　处：《环境工程学报》2009年第6期985-989,共5页Chinese Journal of Environmental Engineering

基　　金：国家自然科学基金项目(40102027;50578151);北京市自然科学基金项目(8052017);北京市教委校企合作项目(51900265005);北京市自然科学基金项目(8092025)

摘　　要：实验中采用了液相还原法制备新型吸附剂纳米铁。在纳米铁低投放量的条件下,采用间歇实验,分别从初始硝酸盐浓度、溶液pH值和温度的不同外界条件下研究了纳米铁对硝酸盐的去除情况。实验结果表明,硝酸盐初始浓度对反应速率有影响,但对去除率影响不大;溶液pH值为2.0时纳米铁对硝酸盐的去除效果最好;随着温度的升高,纳米铁对硝酸盐的去除率有所增加。以t时刻已反应掉的硝酸盐浓度为切入点,提出拟二级动力学方程。进而确定不同温度下的反应速率常数k。实验中k在50℃时最大,为0.014 mg/(L.min)。反应活化能Ea为17.18 kJ/mol,该反应以质量传递为控制因素。溶液中性条件下硝酸盐氮的还原产物为氨氮。Nanoscale Fe^0 systems were employed for removing nitrate solution under different initial conditions, including concentrations of nitrate, pH values and temperatures. According to the batch experiments, the concentration of nitrate showed a little effect on reaction rate but less effect on removal rate. The optimum pH value of removing nitrate is 2.0. The removal rate of nitrate increased along with the increase of temperature. Kinetics analysis from batch studies revealed that the reaction with nanoscale Fe^0 appeared to be a pseudo second- order with respect to the reaction rate constant. The reaction rate reaches 0. 014 mg/（ L·min） at 50℃ which is the highest in the batch experiments. The activation energy is 17.18 kJ/mol. The kinetics of the activation energy shows characteristics of mass transport in addition to reaction control. The main production of nitrate under neutral condition is ammonia.

关 键 词：纳米铁 硝酸盐 反应动力学方程 反应速率常数 活化能 

分 类 号：X703[环境科学与工程—环境工程]