Membrane-based electro-deposition (MED) is an original process promising for reversible removal and recovery of toxic heavy metal ions from wastewater. The removal efficiency of heavy metal ions, however, was limited by the poor membrane surface H₂O splitting in the conventional ion exchange membrane (IEM). Inspired by the amphoteric interface-triggered ion exchange resin regeneration phenomenon in electro-deionization, herein we subtly introduced the amphoteric group into IEM as a proof of concept to solve the above bottleneck. By virtue of the “electronic porter” role of the amphoteric ^-₃OS-R-N(CH₃)₃⁺, the electron extraction from adsorbed H₂O could be accelerated, extending the H₂O splitting from the conventional membrane surface to the bulk membrane interior. Such an H₂O splitting extension favorably produced an intensified and well-modeled OH^- production region at the anodic side of IEM, enhancing the Ni²⁺ basic deposition accordingly. This special characteristic allowed our MED to realize a super-eminent metal ion removal rate (10.5 mol·h^-1·m^-2) along with an ultra-low specific energy consumption (0.1 kWh·mol^-1) for Ni²⁺ removal, which considerably surpassed those of state-of-the-art heavy metal ion removal processes reported yet. Further, the deposited Ni²⁺ could be in situ recovered in conjunction with the facile polarity reversal method. The amphoteric electroactive membrane with high H₂O splitting activity is expected to pave the path to engineering MED for efficient heavy metal ion removal and recovery.

中文翻译：

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巧妙地将两性基团引入电活性膜中，可激发高效的 H2O 分裂，以实现镍 （II） 的可逆去除和回收


基于膜的电沉积 （MED） 是一种原始工艺，有望从废水中可逆地去除和回收有毒重金属离子。然而，传统离子交换膜 （IEM） 中膜表面 H₂O 分裂不良，限制了重金属离子的去除效率。受电去离子中两性界面触发的离子交换树脂再生现象的启发，本文巧妙地将两性基团引入 IEM 中，作为解决上述瓶颈的概念验证。凭借两性 ^-₃OS-R-N（_{CH 3}）₃⁺ 的“电子搬运工”作用，可以加速吸附的 H₂O 的电子提取，将 H₂O 分裂从常规膜表面扩展到块膜内部。这种 H₂O 分裂延伸有利于在 IEM 的阳极侧产生一个强化且建模良好的 OH^- 产生区域，从而增强 Ni²⁺ 碱性沉积。这一特殊特性使我们的 MED 实现了超出色的金属离子去除率 （10.5mol·^h-1·^m-2） 以及超低的 Ni²⁺ 去除比能耗 （0.1 kWh·^mol-1），大大超过了迄今为止报道的最先进的重金属离子去除工艺。此外，沉积的 Ni²⁺ 可以结合简单的极性反转方法进行原位回收。具有高 H₂O 分裂活性的两性电活性膜有望为工程化 MED 以高效去除和回收重金属离子铺平道路。