活性炭与炭黑混合电极的脱盐性能及相关工艺参数的优化

混合电极中各组分的质量比是影响膜电容去离子(membrane capacitive deionization, MCDI)系统脱盐性能的重要因素。重点研究了混合电极中活性材料(活性炭)、导电剂(炭黑)和粘结剂(聚四氟乙烯)3种组分的质量比对MCDI系统脱盐性能的影响，并优化了工艺参数。实验结果表明，在进水氯化钠质量浓度为0.4 g·L⁻¹时，控制活性炭、炭黑及聚四氟乙烯的质量比为8∶1∶1、运行电压为1.2 V，进水流速为4 mL·min⁻¹，MCDI系统具有较优异的脱盐性能，其吸附容量和脱盐速度分别为10.13 mg·g⁻¹和0.44 μmol·(cm²·min)⁻¹，电荷效率和单位能量脱盐量可分别达95.27%和8.23 μmol·J⁻¹；而且，增大进水中氯化钠浓度会进一步提升MCDI系统的吸附容量和脱盐速度，但其脱盐率会有所降低。吸附热力学和动力学拟合结果表明，此混合电极材料脱盐过程分别符合Freundlich吸附等温方程和准二级动力学方程。

Optimization of membrane capacitive deionization performance of activated carbon and carbon black mixed electrode

The mass ratio of each component in the mixed electrode is an important factor for the desalination performance of membrane capacitor deionization (MCDI). In this study, the effects of the mass ratio of active ingredient (activated carbon), conductive agent (carbon black) and binder (polytetrafluoroethylene) on the desalination performance of MCDI were investigated, and the operation parameters were optimized. The experimental results showed that the MCDI system had a good desalination performance when the influent sodium chloride concentration was 0.4 g·L−1, the mass ratio of activated carbon, carbon black and polytetrafluoron was 8∶1∶1, the operating voltage was 1.2 V and the influent flow rate was 4 mL·min−1. The adsorption capacity and desalination rate were 10.13 mg·g−1 and 0.44 μmol·cm−2·min−1, respectively, charge efficiency and unit energy desalination capacity could reach 95.27% and 8.23 μmol·J−1, respectively. Moreover, the increase of the influent sodium chloride concentration could further improve the adsorption capacity and desalination rate of MCDI system, but the desalination rate decreased. The fitting results of adsorption thermodynamics and kinetics showed that the desalination process of the mixed electrode material conforms to Freundlich adsorption isothermal equation and second-order kinetic equation, respectively.