膜电吸附除盐用双电极制备及性能研究

Study on Preparation and Performance of Bipolar Eletrodes for Membrane Capacitive Deionization

以超级电容活性炭为电吸附电极材料,以复合导电膜为电极导电集流体,采用平板加热压制成型工艺,制备了膜电吸附除盐(MCDI)用双电极。比较了柔性石墨片、高密度石墨板和复合导电膜3种集流体的导电性能和防水性能,筛选出复合导电膜为双电极集流体。从平压压力和温度方面对双电极制备成型工艺进行优化。测试了双电极在MCDI模组中的电化学循环稳定性和脱盐性能。结果表明,制备成型优化的压力为100t、温度为90℃。包含4个双电极和1对端电极的MCDI模组,当进水NaCl的质量浓度为820mg/L的盐水以500mL/min的体积流量一次性流过MCDI时,该模组充放电效率99.3%,循环450次仍保持电化学性能稳定,出水NaCl的质量浓度为376mg/L,脱盐率为54%。

The symmetric activated carbon bipolar electrodes for membrane capacitive deionization(MCDI)were prepared with flat plate heating and pressing forming process,and supercapacitive activated carbon(AC)as eletrochemical adsorption material and conductive composite membrane as current collector.The conductivity and waterproofness of current collectors including flexible graphite sheet,high density graphite plate and conductive composite membrane were compared.The double electrode preparation and forming process was optimized from the aspect of flat pressure and temperature.The electrochemical cycling stability and desalination performance of the dual electrodes in the MCDI module were tested.The results showed that,the optimized pressure and the temperature for preparation and forming process was 100 t and 90℃.A MCDI module with 4 bipolar electrodes and 1 pair of end electrode was assembled,when the brine with a mass concentration of influent NaCl of 820 mg/L flowed through the MCDI once at a volume flow of 500 mL/min,the charging and discharging efficiency of the module was 99.3%,the electrochemical performance was still stable after 450 cycles,the mass concentration of NaCl in the effluent was 376 mg/L,and the salt rejection rate was 54%.