Chemical removal of nitrate from water by aluminum-iron alloys
Chemical removal of nitrate from water by aluminum-iron alloys
复制标题
铝铁合金化学去除水中硝酸盐
DOI：
10.1016/j.chemosphere.2016.09.102
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发表时间：
2017
期刊：
影响因子：
8.8
通讯作者：
Fisher Adrian
中科院分区：
文献类型：
--
作者：
Xu Jie;Pu Yuan;Qi Wei-Kang;Yang Xiao Jin;Tang Yang;Wan Pingyu;Fisher Adrian
零价铁在水中硝酸盐的化学还原中已被深入研究，但还原需要酸性或弱酸性pH条件，还原产物仅为铵，这是一种毒性更大的物质。零价铝是比铁更强的还原剂，但其用于还原硝酸盐水溶液需要相当碱性的pH条件。在这项研究中，铝-铁合金与铁含量为10%，20%和58%（分别称为Al-Fe 10，Al-Fe 20和Al-Fe 58，分别）的硝酸盐溶液的还原进行了研究。Al-Fe合金在pH 2-12范围内对水中硝酸盐的还原都是有效的，在接近中性的pH条件下，还原反应按准一级反应进行。Al-Fe_（10）的反应速率常数（Kobs）是Fe的3倍，Al-Fe_（20）的Kobs是Al-Fe_（10）的2倍。Al-Fe 10、Al-Fe 20和Al-Fe 58还原的氮选择性在pH 7时分别为17.6%、23.9%和40.3%，Al-Fe 20还原的氮选择性从pH 2时的18.9%增加到pH 12时的60.3%。Al-Fe合金的选择性和反应性的提高可能是由于金属间化合物（Al 13 Fe 4）的存在。
Zero-valent iron has been intensively investigated in chemical reduction of nitrate in water, but the reduction requires acidic or weak acidic pH conditions and the product of the reduction is exclusively ammonium, an even more toxic substance. Zero-valent aluminum is a stronger reductant than iron, but its use for the reduction of aqueous nitrate requires considerably alkaline pH conditions. In this study, aluminum-iron alloys with an iron content of 10%, 20% and 58% (termed Al-Fe10, Al-Fe20 and Al-Fe58, respectively) were investigated for the reduction of aqueous nitrate. Al-Fe alloys were efficient to reduce nitrate in water in an entire pH range of 2–12 and the reduction proceeded in a pseudo-first order at near neutral pH conditions. The observed reaction rate constant (Kobs) of Al-Fe10 was 3 times higher than that of Fe and the Kobsof Al-Fe20 doubled that of Al-Fe10. The nitrogen selectivity of the reduction by Al-Fe10, Al-Fe20 and Al-Fe58 was 17.6%, 23.9% and 40.3%, respectively at pH 7 and the nitrogen selectivity by Al-Fe20 increased from 18.9% at pH 2–60.3% at pH 12. The enhanced selectivity and reactivity of Al-Fe alloys were likely due to the presence of an intermetallic Al-Fe compound (Al13Fe4).