还原铁粉去除地下水中硝酸盐氮的研究

地下水中硝酸盐氮的污染问题变得日益突出,为此以100～200目的铁粉为还原剂,采用静态试验方法研究了不同pH值、硝酸盐氮初始浓度、溶解氧、铁粉表面预处理及铁与硝酸盐氮的质量比等因素对硝酸盐氮去除率的影响。结果表明,溶液的初始pH值对硝酸盐氮的去除影响很大,pH>4时,铁粉几乎不与水中硝酸盐氮进行反应;铁粉经过表面处理后在同一时刻内对硝酸盐氮的去除率提高1倍多;铁与硝酸盐氮的最佳质量比为200∶1;溶解氧对硝酸盐氮的去除没有太大影响;反应产物主要是氨氮。

Nitrate Reduction by Zero-Valent Iron from Groundwater

In this paper chemical reduction of nitrate by metallic iron(Fe0)was studied as a potential technology to remove nitrate from water.Under experimental conditions 100~200 mesh zero-valent iron was used as the reducing agent.And the effect of initial pH,concentration of nitrate,DO,iron-to-nitrate ratio and the iron surface pre-treatment on both nitrate reduction rate and percent removal were investigated through batch experiments.The results of batch experiments conducted in an iron/nitrate/water system showed that nitrate removal was strongly dependent on initial pH and nitrate could be rapidly reduced to ammonium at pH 2~4.And nitrate removal was accompanied by a pH increase,DO decrease and solution iron increase.The nitrate removal rate of polished iron was 2 times higher than that of that of unpolished iron granular.In the denitrification process,the rate of nitrate reduction by iron increased with increasing nitrate concentration and DO might not have little effect on the nitrate removal.Our conclusion is that the optimal quality ratio of iron-to-nitrate as N was 200:1;And the mass balance of nitrate reduction with iron at low pH indicated that endproducts mainly are ammonia.