零价纳米铁炭微电解体系去除水中硝酸盐

Removal of nitrate from water by nano-zero-valent iron-carbon microelectrolysis system

用液相还原法制备以活性炭为载体的负载型纳米铁(NZVI/AC),采用不同分散剂合成NZVI/AC,对材料进行XRD、SEM等表征,用制备的材料进行硝酸盐批实验,考察不同分散剂条件下合成的材料对硝酸盐氮的还原情况,再进一步分析硝酸盐氮的还原过程以及动力学.结果显示用聚乙烯吡咯烷酮(PVP)作为分散剂得到性能较好的NZVI/AC,且该体系存在微电解作用,硝酸盐氮的还原过程首先是纳米铁对硝酸根的吸附,然后再发生还原反应,产物以氨氮为主,中间产物有亚硝酸盐的生成,符合准一级反应动力学方程.

In this paper, nanoscale zero-valent iron supported on activated carbon （NZVI/AC） was synthesized using a liquid phase reduction method with different dispersants. The NZVI/AC was characterized by X-ray diffraction （XRD） and scanning electron microscopy （SEM）. The produced NZVI/AC was tested in batch experiments for nitrate removal, and the reduction process and kinetics of nitrate reduction were then studied. The results showed that the performance of the NZVI/AC with polyvinylpyrrolidone （PVP） was better than other samples. In addition, the system had micro electrolysis function. The reduction process of nitrate by NZVI/AC proceeded in two steps： Firstly, nitrate was adsorbed on the nanoscale iron, and then the redox reaction took place. The process obeyed pseudo first order reaction. The main reduction products were ammonia nitrogens, and nitrite was the reaction intermediate.