Zhang Jingqi, Song Ying, Chao Jingbo, Huang Hai, Liu Dazhi, Coulon Frederic, Yang Xiao Jin
State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing, 100029, China.
Research & Development Centre, China State Science Dingshi Environmental Engineering Co., Ltd, Beijing, 100102, China.
Heliyon. 2023 Dec 6;10(1):e23422. doi: 10.1016/j.heliyon.2023.e23422. eCollection 2024 Jan 15.
Zero-valent iron (ZVI) has been extensively studied for its efficacy in removing heavy metals, nitrate, and chlorinated organic compounds from contaminated water. However, its limited effectiveness due to rapid passivation and poor selectivity is prompting for alternative solutions, such as the use of aluminium alloys. In this study, the efficacy of five distinct aluminium alloys, namely Al-Mg, Al-Fe, Al-Cu, and Al-Ni, each comprising 50 % Al by mass at a concentration of 10 g/L, was assessed using copper, nitrate and trichloromethane (TCM) as model contaminants. Results show that chemical pollutants reacted immediately with Al-Mg. On the contrary, the remaining three alloys exhibited a delay of 24 h before demonstrating significant reactivity. Remarkably, Al-Mg alloy reduced nitrate exclusively to ammonium, indicating minimal preference for nitrate reduction to N. In contrast, the Al-Cu, Al-Ni, and Al-Fe alloys exhibited N selectivity of 3 %, 5 %, and 19 %, respectively. The removal efficiency of copper, nitrate and TCM reached 99 % within 24 h, 95 % within 48h and 48 % within 48h, respectively. Noteworthy findings included the correlation between Fe concentration within the Al-Fe alloy and an increased N selectivity from 9.3 % to 24.1 %. This resulted in an increase of Fe concentration from 10 % to 58 % albeit with a concurrent reduction in reactivity. Cu removal by Al-Fe alloy occurred via direct electron transfer, while the removal of nitrate and TCM was facilitated by atomic hydrogen generated by the alloy's hydrolysis. Intriguingly, nitrate and TCM suppressed Cu reduction, whereas Cu improved nitrate reduction and TCM degradation. These findings demonstrate the great potential of Al-Mg and Al-Fe alloys as highly efficient agents for water remediation.
零价铁（ZVI）因其在去除受污染水中的重金属、硝酸盐和氯代有机化合物方面的功效而受到广泛研究。然而，由于其快速钝化和选择性差导致效果有限，促使人们寻求替代解决方案，例如使用铝合金。在本研究中，以铜、硝酸盐和三氯甲烷（TCM）作为模型污染物，评估了五种不同的铝合金，即Al-Mg、Al-Fe、Al-Cu和Al-Ni，每种合金的铝质量分数均为50%，浓度为10 g/L。结果表明，化学污染物与Al-Mg立即发生反应。相反，其余三种合金在表现出显著反应性之前有24小时的延迟。值得注意的是，Al-Mg合金仅将硝酸盐还原为铵，表明其对硝酸盐还原为N的偏好极小。相比之下，Al-Cu、Al-Ni和Al-Fe合金的N选择性分别为3%、5%和19%。铜、硝酸盐和TCM的去除效率分别在24小时内达到99%；48小时内达到95%；48小时内达到48%。值得注意的发现包括Al-Fe合金中Fe浓度与N选择性从9.3%增加到24.1%之间的相关性。这导致Fe浓度从10%增加到58%，尽管同时反应性有所降低。Al-Fe合金去除铜是通过直接电子转移，而硝酸盐和TCM的去除则由合金水解产生的原子氢促进。有趣的是，硝酸盐和TCM抑制了铜的还原，而铜则促进了硝酸盐的还原和TCM的降解。这些发现证明了Al-Mg和Al-Fe合金作为高效水修复剂的巨大潜力。
