Henan Key Laboratory for Synergistic Prevention of Water and Soil Environmental Pollution, School of Geographic Sciences, Xinyang Normal University, Xinyang, 464000, China.
Key Laboratory for Yellow River and Huai River Water Environment and Pollution Control, Ministry of Education, Henan Key Laboratory for Environmental Pollution Control, School of Environment, Henan Normal University, Xinxiang, 453007, China.
J Environ Manage. 2024 Apr;356:120719. doi: 10.1016/j.jenvman.2024.120719. Epub 2024 Mar 22.
Nitrate pollution in surface water and ground water has drawn wide attention, which has brought challenges to human health and natural ecology. Electroreduction of nitrate to NH in waste water was a way to turn waste into wealth, which has attracted interest of many researchers. Using Nickel foam as substrate, we prepared Pd/In bimetallic electrode (NF-Pd/In) according to a two-step electrodeposition method. There are many irregularly shaped particles in the size range of 10 nm-100 nm accumulated on the surface of prepared NF-Pd/In electrode, which could supply high specific area and more active sites for nitrate electroreduction. FESEM-EDS, XRD and XPS analysis confirmed the uniform distribution of Pd and In on the surface of prepared NF-Pd/In electrode, with a mass ratio of 4.5/1. Above 96% of 100 mg/L NO-N was removed and 95% of NH selectivity was reached after 5 h of reaction under -1.6 V vs. Ag/AgCl sat. KCl when using 0.05 mol/L of NaSO as electrolyte. High concentration of NaCl (0.05 mol/L) in the test solution dramatically decreased the NH selectivity because the produced NH could be further oxidized to N by the formed HClO from Cl. EIS tests indicated that the prepared NF-Pd/In electrode showed much lower electrode resistance than NF due to the adsorptive property and electrocatalytic ability for nitrate removal. Density functional theory (DFT) calculations indicated that the presence of In could promote the conversion of NO to *NO during the process of nitrate electroreduction to NH. Circulating tests demonstrated the stability of prepared NF-Pd/In electrode.
地表水中和地下水中的硝酸盐污染已引起广泛关注，这给人类健康和自然生态带来了挑战。将废水中的硝酸盐还原为 NH 是一种变废为宝的方法，引起了许多研究人员的兴趣。我们采用泡沫镍作为基底，通过两步电沉积法制备了 Pd/In 双金属电极（NF-Pd/In）。在制备的 NF-Pd/In 电极表面，堆积有许多尺寸在 10nm-100nm 范围内的形状不规则的颗粒，这为硝酸盐的电还原提供了高比表面积和更多的活性位点。FESEM-EDS、XRD 和 XPS 分析证实 Pd 和 In 均匀分布在制备的 NF-Pd/In 电极表面，质量比为 4.5/1。在 -1.6 V 相对于 Ag/AgCl sat. KCl 下，当使用 0.05mol/L 的 NaSO 作为电解质时，反应 5h 后，100mg/L 的 NO-N 去除率达到 96%以上，NH 选择性达到 95%。在测试溶液中高浓度的 NaCl（0.05mol/L）会显著降低 NH 选择性，因为产生的 NH 可能被形成的 HClO 进一步氧化为 N。EIS 测试表明，由于对硝酸盐去除具有吸附性能和电催化能力，制备的 NF-Pd/In 电极的电极电阻明显低于 NF。密度泛函理论（DFT）计算表明，In 的存在可以促进硝酸盐电还原为 NH 的过程中 NO 向*NO 的转化。循环测试证明了制备的 NF-Pd/In 电极的稳定性。
