Ionic contaminants, especially heavy metal ions, are a significant challenge for ensuring the safety and quality of drinking water. Electrosorption and membrane separation are effective technologies to remove ionic contaminants; however, the constant electricity demand and lack of selectivity limit their further application. In this study, a low-pressure membrane with an electrically tuning surface charge was developed for the selective and efficient removal of hexavalent chromium (Cr(VI)) from water. Poly(vinyl ferrocene) (PVF) was used to fabricate an electrically responsive interface, and an activated carbon felt (ACF) was applied as a conductive substrate. Fluorescence characterization was then used to further highlight its redox properties and the tunability of its surface charge. The activated PVF-based electro-responsive adsorptive membrane (PERAM) showed an excellent adsorption capacity and selectivity for Cr(VI) during single-pass filtration. Notably, regeneration was achieved by the application of a reversed electric potential without the need for additional chemical additives. The Cr(VI) effluent concentration was reduced to less than 0.05 mg/L at a high flux of 424 L/m²·h, and it had a treatment capacity of greater than 5140 L/m² due to effective activation and regeneration. The electrostatic force changes between the PVF and Cr(VI) at different potentials was the key mechanism that allowed for the rapidly reversible adsorption-desorption of Cr(VI) according to the results of the density functional theory (DFT) calculations and molecular dynamics (MD) simulations.

中文翻译：

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电调谐低压膜表面电荷，可高效去除饮用水中的 Cr（VI）

离子污染物，尤其是重金属离子，是确保饮用水安全和质量的重大挑战。电吸附和膜分离是去除离子污染物的有效技术;然而，恒定的电力需求和缺乏选择性限制了它们的进一步应用。在这项研究中，开发了一种具有电调谐表面电荷的低压膜，用于选择性和有效地去除水中的六价铬 （Cr（VI））。聚乙烯二茂铁 （PVF） 用于制造电响应界面，活性炭毡 （ACF） 用作导电基材。然后使用荧光表征进一步突出其氧化还原特性和表面电荷的可调性。活化的 PVF 基电响应吸附膜 （PERAM） 在单通道过滤过程中表现出优异的吸附能力和对 Cr（VI） 的选择性。值得注意的是，再生是通过施加反向电位实现的，而无需额外的化学添加剂。在 424 L/m²·h 的高通量下，Cr（VI） 流出物浓度降至 0.05 mg/L 以下，并且由于有效的活化和再生，其处理量大于 5140 L/m²。根据密度泛函理论 （DFT） 计算和分子动力学 （MD） 模拟的结果，PVF 和 Cr（VI） 在不同电位下的静电力变化是允许 Cr（VI） 快速可逆吸附-解吸的关键机制。