Recently, the reaction speed and cycle performance of hexavalent chromium reduction over microsized zero-valent iron (ZVI) with an Fe⁰ core and iron oxide (FeO_x) shell structure have been improved by activating the Fe⁰-core electrons through electromagnetic coupling between Fe⁰-core electrons and charges (hexavalent chromium in solution, double-charge layers of the ZVI/solution interface). Herein, the abovementioned electromagnetic coupling was greatly increased by adding salt (CH₃COONa, NaCl, NaNO₃, and Na₂SO₄) in the hexavalent chromium solution to increase the charge response. Adding salt greatly improved the reaction speed and cycle performance of hexavalent chromium reduction. It took 8 min to reduce hexavalent chromium with CH₃COONa to below the discharge standard of wastewater in the first cycle and 20 min after reducing for 20 cycles. The best apparent rate of constant value (0.416 (min)^-1) is nearly four times larger than those without salts. X-ray diffraction and X-ray photoelectron spectroscopy revealed the production of amorphous iron oxide shell with salt. The salt improves the hexavalent chromium reduction speed and cycle performance and impedes the Fe⁰-core-electron transfer via the produced Fe₂O₃, resulting in existence of an optimized salt dosage. This work aims to provide an effective route for enhancing the removal efficiency and cycle performance of heavy-metal–ion reduction via Fe⁰. And this work also proposes a novel viewpoint that adding salt in waste water would increase the electromagnetic coupling between the charges in solution and Fe⁰-core electrons which could finally activate the redox reaction.

最近，通过Fe ⁰核和氧化铁（FeO _x ）壳结构的微米级零价铁（ZVI）还原六价铬的反应速度和循环性能，通过之间的电磁耦合激活Fe ⁰核电子得到了提高。 Fe ⁰ -核心电子和电荷（溶液中的六价铬，ZVI/溶液界面的双电荷层）。在此，通过在六价铬溶液中添加盐(CH ₃ COONa、NaCl、NaNO ₃和Na ₂ SO ₄ )以增加电荷响应，大大增加了上述电磁耦合。添加盐大大提高了六价铬还原的反应速度和循环性能。首次循环用CH ₃ COONa还原六价铬需要8 min，达到废水排放标准以下，还原20个循环后需要20 min。最佳表观恒定值速率(0.416(min) ^-1 )比无盐的大近四倍。 X射线衍射和X射线光电子能谱揭示了带有盐的无定形氧化铁壳的产生。该盐提高了六价铬的还原速度和循环性能，并阻碍了通过产生的Fe ₂ O ₃的Fe ⁰核电子转移，从而导致存在优化的盐剂量。本工作旨在为提高Fe ⁰还原重金属离子的去除效率和循环性能提供有效途径。 这项工作还提出了一个新的观点，即在废水中添加盐会增加溶液中电荷与Fe ⁰核电子之间的电磁耦合，最终激活氧化还原反应。