Nitrite-containing wastewater poses an imminent threat to both human health and ecosystems. Conventional methods like nitrification and denitrification rely heavily on chemical reagents, while emerging membrane separation has limitations in permselectivity. Here, a conductive membrane with both electroresponsive and electrocatalytic capabilities was developed by integrating Keggin-type polyoxometalates (POMs) through combining layer-by-layer self-assembly and interfacial polymerization. The pore size of the membranes remained largely unaffected by an electric field, but its Donnan effect was significantly enhanced, leading to a substantial increase in nitrite removal from 23.1% to an impressive 81%. Nitrite underwent a reductive degradation at the cathode, producing nitrogen-containing gases (8.3%), while oxidation at the anode yielded hypotoxic NO (11.3%), respectively exhibiting 79.9% rejection of NO and 83.1% rejection of NO under the electric field-enhanced Donnan effect. Therefore, the high-level total nitrogen removal was composed of three key components: 64.2% from direct NO rejection, 9.4% from oxidation-generated NO rejection, and 7.4% attributed to gas generation. Significantly, our work underscored the consistently robust structural stability of the POMs-based membrane under an electric field, maintaining an outstanding total nitrogen removal exceeding 75%. Consequently, this research introduced a promising electrochemical-membrane fusion approach for efficiently removing high-activity nitrite-containing wastewater, emphasizing the potential for environmental applications.

中文翻译：

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构建基于多金属氧酸盐的电催化纳滤膜去除亚硝酸盐

含亚硝酸盐废水对人类健康和生态系统构成迫在眉睫的威胁。硝化和反硝化等传统方法严重依赖化学试剂，而新兴的膜分离在选择性渗透方面存在局限性。在此，通过结合层层自组装和界面聚合，集成了Keggin型多金属氧酸盐（POM），开发了一种兼具电响应和电催化能力的导电膜。膜的孔径在很大程度上不受电场影响，但其唐南效应显着增强，导致亚硝酸盐去除率从 23.1% 大幅增加到令人印象深刻的 81%。亚硝酸盐在阴极发生还原降解，产生含氮气体（8.3%），而在阳极氧化产生低毒NO（11.3%），在电场作用下，NO的排斥率分别为79.9%和83.1%。增强唐南效应。因此，高水平的总氮去除率由三个关键部分组成：64.2%来自直接NO截留，9.4%来自氧化生成的NO截留，7.4%归因于气体生成。值得注意的是，我们的工作强调了基于 POM 的膜在电场下始终保持强大的结构稳定性，保持了超过 75% 的出色总氮去除率。因此，这项研究引入了一种有前途的电化学膜融合方法，可有效去除高活性的含亚硝酸盐废水，强调了环境应用的潜力。