氢气还原针铁矿去除水中的亚硝酸盐

Removal of Nitrite in Wastewater with Goethite Reduced by Hydrogen

采用氢气还原天然针铁矿和合成针铁矿制备铁粉,研究了反应时间、反应pH值、初始亚硝酸盐浓度等对两种还原铁粉去除亚硝酸盐的影响。结果表明:反应3 h、低亚硝酸盐初始浓度(<16 mg/L)、低铁粉与亚硝酸盐质量比(<33:1)情况下,由合成针铁矿制备的还原铁粉对亚硝酸盐的去除率均高于由天然针铁矿制备出的铁粉,但随着反应时间的延长(>3 h)、亚硝酸盐初始浓度的增加(>16 mg/L)、铁粉与亚硝酸盐质量比的增加(>33:1),由天然针铁矿制备的还原铁粉对亚硝酸盐的去除率均高于由合成针铁矿制备出的铁粉。Al部分替代天然针铁矿中Fe阻碍了铁粉表面钝化膜的形成,从而增加了还原铁粉还原亚硝酸盐的稳定性,提高了亚硝酸盐的去除率。

Reduced iron powders were obtained via the reduction of natural goethite and symhetic goethite by hydrogen. Effects of reaction time, pH value, initial nitrite concentration on the removal rate of nitrite by two kinds of reduced iron powders were investi- gated. The results show that nitrite removal rate by the reduced iron powder prepared by reduction of synthetic goethite is greater than that reduction of natural goethite when reaction time is 〈 3 h, initial nitrite concentration is 〈 16 mg/L and ratio of iron-to-nitrite is 〈 33：1. However, nitrite removal rate by the reduced iron powder prepared from natural goethite is greater than nitrite removal rate by the reduced iron powder prepared from synthetic goethite when reaction time is 〉 3 h, initial nitrite concentration is 〉 16 mg/L and ratio of iron-to-nitrite is 〉 33：1. The substitution of aluminum in the structure of goethite affects the formation of passivation film on iron powder, increasing the stability of iron powder for the removal of nitrite and the nitrite removal efficiency.