氢气还原针铁矿制备的纳米铁去除硝酸盐的研究

Study on Nitrate Removal with Nanoscale Zero-valent Iron Prepared by Hydrogen Reducing Goethite

采用氢气还原天然针铁矿法制备出粒径为14 nm的单质铁纳米材料,考察了该纳米铁对水中硝酸盐的去除特性及影响因素,并与普通铁粉进行了对比。结果表明,与普通铁粉相比,纳米铁粉对硝酸盐的去除效果受pH值的影响较小;在纳米铁粉与硝酸盐的质量比为40∶1、反应时间为5 h、硝酸盐初始浓度为60 mg/L的条件下,纳米铁对硝酸盐具有较高的还原活性,对硝酸盐的去除率可达90%以上,且还原产物中基本无亚硝酸盐;溶解氧和天然针铁矿粒径对纳米铁去除硝酸盐的影响不大。采用氢气还原天然针铁矿制备纳米铁的方法简单且成本较低,在去除地下水中的硝酸盐方面具有很好的应用前景。

Nanoscale zero-valent iron （NZVI） with particle size of 14 nm was prepared by hydrogen reducing natural goethite. The nitrate removal by NZVI and the effect factors were investigated, and the comparison between NZVI and ordinary zero-valent iron （OZVI） was made. The results show that the removal efficiency of nitrate by NZVI is less influenced by pH value when compared with OZVI. The removal rate of nitrate can reach more than 90% when the iron-to-nitrate ratio is 40 ： 1, the reaction time is 5 h and the nitrate concentration is 60 mg/L. NZVI has high reduction activity for nitrate, and the end products have no nitrite. The dissolved oxygen and natural goethite particle size have less effect on nitrate removal. This method is relatively simple and low in cost, so NZVI has potential application in nitrate removal from groundwater.