Capacitive deionization (CDI) has been widely studied as a highly efficient method for the removal of charged pollutants in sewage. However, the control of ion selectivity has always been challenging, limiting the application of this approach. In this article, the regulation of different acid/base functional group distributions on the selectivity of four anions are comprehensively discussed. The effects are quantified through simulations and statistical analysis. Finally, optimized CDI is used for the simultaneous denitrification and dephosphorization of municipal wastewater. The results show that carboxyl groups significantly promote the selectivity of dihydrogen phosphate and that amino groups promote the selectivity of sulfate and dihydrogen phosphate. Density functional theory is used to calculate the influence of the functional groups on the anion adsorption energy. Compared with other anions, the energy released is improved when carboxyl groups are included in the adsorption of dihydrogen phosphate. The increase in the released energy is highest when amino groups participate in the adsorption of sulfate and is second-highest when they participate in the adsorption of dihydrogen phosphate. Statistical analysis shows that the valence and hydration energy of the anion and the effect of the functional groups on anion adsorption are significantly related to anion adsorption (P < 0.05), and the correlation coefficient of the model is 0.7253. A CDI stack for the removal of phosphorus and nitrogen under high background ion concentrations is constructed and applied, and it is shown that the treated wastewater meets higher discharge standards. Moreover, the method reaches nearly 80% water production under optimized operating modes. This study reveals the importance of functional groups in ion-selective regulation and provides a potential method for high-standard wastewater treatment.

电容去离子（CDI）作为一种去除污水中带电污染物的高效方法已被广泛研究。然而，离子选择性的控制一直具有挑战性，限制了这种方法的应用。本文全面探讨了不同酸碱官能团分布对四种阴离子选择性的调控。通过模拟和统计分析对影响进行量化。最后，优化的CDI用于城市污水的同时脱硝和脱磷。结果表明，羧基显着促进磷酸二氢盐的选择性，氨基促进硫酸盐和磷酸二氢盐的选择性。密度泛函理论用于计算官能团对阴离子吸附能的影响。与其他阴离子相比，当羧基参与吸附磷酸二氢盐时，释放的能量有所提高。当氨基参与硫酸盐的吸附时释放能量的增加最高，而当它们参与磷酸二氢盐的吸附时释放能量的增加是第二高的。统计分析表明，阴离子的化合价和水合能以及官能团对阴离子吸附的影响与阴离子吸附显着相关（当氨基参与硫酸盐的吸附时释放能量的增加最高，而当它们参与磷酸二氢盐的吸附时释放能量的增加是第二高的。统计分析表明，阴离子的化合价和水合能以及官能团对阴离子吸附的影响与阴离子吸附显着相关（当氨基参与硫酸盐的吸附时释放能量的增加最高，而当它们参与磷酸二氢盐的吸附时释放能量的增加是第二高的。统计分析表明，阴离子的化合价和水合能以及官能团对阴离子吸附的影响与阴离子吸附显着相关（P  < 0.05)，模型的相关系数为 0.7253。构建并应用了高背景离子浓度下除磷除氮的CDI烟囱，结果表明处理后的废水符合较高的排放标准。此外，该方法在优化的操作模式下可达到近 80% 的产水量。该研究揭示了官能团在离子选择性调节中的重要性，并为高标准废水处理提供了一种潜在的方法。