Conventional technologies for ammonium removal from wastewaters are based on biological conversion to nitrogen gas, eliminating the possibility for ammonium recovery. A new electrochemical approach was developed here to selectively remove ammonium using two copper hexacyanoferrate (CuHCF) battery electrodes separated by an anion exchange membrane, at low applied voltages (0.1 to 0.3 V). The CuHCF battery electrodes removed NH₄⁺ from a synthetic wastewater with a selectivity >5 (i.e., percent removed of NH₄⁺/percent removed of Na⁺) when operated with a 0.1 V applied voltage, despite the much higher initial Na⁺ concentration in the sample (20 mM) than NH₄⁺ (5 mM). In contrast, we observed only negligible selective removal of NH₄⁺ over Na⁺ (<2) when using nonselective electrodes or ion-selective membranes (10 mM Na⁺, 5 mM NH₄⁺, 0.1 V). The selectivity further increased to 9 when using equimolar concentrations of NH₄⁺ and Na⁺ (10 mM). With an actual domestic wastewater, the CuHCF electrodes removed 85% of NH₄⁺ (3.4 to 0.5 mM) with a selectivity >4 versus Na⁺ in the presence of other competing cations. These results demonstrate that CuHCF electrodes can be used to selectively remove NH₄⁺ from various waters containing multiple ions.

中文翻译：

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使用选择性电池电极去除生活污水中的氨

从废水中去除铵的常规技术是基于生物转化为氮气的技术，从而消除了回收铵的可能性。在这里，开发了一种新的电化学方法，以在低施加电压（0.1至0.3 V）下，使用两个由阴离子交换膜隔开的六氰合铁酸铜（CuHCF）电池电极选择性去除铵。尽管初始Na ⁺浓度要高得多，但CuHCF电池电极在施加0.1 V电压时仍能从合成废水中去除NH ₄ ⁺，其选择性> 5（即NH ₄ ⁺去除百分比/ Na ⁺去除百分比）。样品中（20 mM）比NH ₄ ⁺（5毫米）。相反，当使用非选择性电极或离子选择性膜（10 mM Na ⁺，5 mM NH ₄ ⁺，0.1 V）时，我们仅观察到在Na ⁺（<2）上选择性忽略的NH ₄ ⁺去除。当使用等摩尔浓度的NH ₄ ⁺和Na ⁺（10 mM）时，选择性进一步提高到9 。对于实际的生活废水，在存在其他竞争性阳离子的情况下，CuHCF电极相对于Na ⁺的选择性> 4 ，去除了85％的NH ₄ ⁺（3.4至0.5 mM）。这些结果表明，CuHCF电极可用于选择性去除NH ₄ ⁺ 来自含有多种离子的各种水。