Flow-electrode capacitive deionization (FCDI) technology has been demonstrated to be a promising approach for ammonia removal and recovery. The flow-electrode, where adsorption and desorption occur, is one of the most significant parts in FCDI cells. However, in previous studies, the influence of concentrations in the electrolyte was not well understood, which greatly influenced system performances. In this study, we initially evaluated FCDI performance by using electrolytes containing different amounts of activated carbon (AC), as well as initial ammonium concentrations. Results indicated that compared to concentration factors (CFs), the effect of AC contents on the deionization process was almost neglectable. To achieve efficient ammonia removal and enrichment, initial CF below 10 and refreshment of flow-electrode when CF exceeded 100 were recommended. Further experiments indicated that the poor system performance under high initial CF was caused by concentration polarization and ion back diffusion. The long-term experiment confirmed the above conclusion. Besides, a high concentration of 5600 mg·L⁻¹ was gained for ammonia recovery. This study demonstrated that the concentration in the electrolyte needs to be considered carefully to maintain the system in an efficient and economic state.

流电极电容去离子（FCDI）技术已被证明是一种有前途的氨去除和回收方法。发生吸附和解吸的流电极是FCDI电池中最重要的部分之一。但是，在以前的研究中，对电解质中浓度的影响还没有很好的理解，这极大地影响了系统性能。在这项研究中，我们最初通过使用包含不同量的活性炭（AC）以及初始铵浓度的电解质来评估FCDI性能。结果表明，与浓缩因子（CFs）相比，AC含量对去离子过程的影响几乎可以忽略不计。为了有效去除和富集氨，建议初始CF低于10，并建议CF超过100时刷新流电极。进一步的实验表明，高初始CF下较差的系统性能是由浓度极化和离子反向扩散引起的。长期实验证实了以上结论。另外，高浓度5600 mg·L获得^-1以回收氨。这项研究表明，需要仔细考虑电解质中的浓度，以使系统保持高效和经济的状态。