流动电极电容去离子是一种可连续运行、低能耗的新型电化学脱盐技术。在流动电极中添加导电剂是提升其脱盐性能的常用手段，但常用的导电剂如炭黑(carbon black CB)、碳纳米管(carbon nanotubes CNT)等的强疏水性会影响流动电极的电子传递效率和流动性，因此，提高导电剂亲水性并充分利用其吸附能力是提高流动电极脱盐性能的关键。本研究利用H2O2对炭黑进行氧化改性，通过调节氧化时间，制备了系列具有不同亲水性、表面含氧官能团的炭黑改性材料(CBO)，并对其进行了详细的物理和电化学特性表征。在此基础上进一步探究了系列炭黑材料作为导电剂对装置脱盐效果的影响规律，同时优化了系统运行参数。结果表明，由H2O2氧化12 h所制备的炭黑材料作为导电剂时，装置具有较好的脱盐性能，在CBO-12投加量为0。25％、施加电压为1。2 V时，装置的平均除盐速率和电荷效率分别为0。464 μmol·(cm2·min)-1和83。1％。进一步表征发现，优异的脱盐性能归因于适当的氧化改性，可有效改善CB的疏水性，并在其表面引入大量含氧官能团，在改善流动电极电荷传递能力的同时，还能充分利用改性CB的吸附性能。
Enhancement mechanism of desalination performance of the flow electrode capacitive deionization by modified carbon black conductive agent
Flow electrode capacitive deionization is a new electrochemical desalination technology which can run continuously and has low energy consumption.Adding a conductive agent to the flow electrode is an effective method to improve the desalination performance of the flow electrode.However,the strong hydrophobicity of commonly used conductive agents(such as carbon black CB,carbon nanotubes CNT)will affect the electron transfer efficiency and the fluidity of the flow electrode.Therefore,how to increase the hydrophilicity of the conductive agent and make full use of its adsorption capacity is the key to improve the desalination performance of the flow electrode.In this study,a series of carbon black modified materials(CBO)with different hydrophilic properties and surface oxygen-containing functional groups were prepared by adjusting the oxidation time with H2O2 oxidation,and the detailed physical and electrochemical properties were characterized.On this basis,the effect of series of carbon black materials as conductive agent on the desalination effect of the device was further explored,and the operating parameters of the system were optimized.The experimental results showed that the device had a good performance when the carbon black material prepared by H2O2 oxidation for 12 hours was used as the conductive agent.When the dosage of CBO-12 was 0.25％and the applied voltage was 1.2 V,the average desalination rate and charge efficiency of the device could reach 0.464μmol·(cm2·min)-1 and 83.1％,respectively.Further characterization showed that the excellent desalination performance was due to proper oxidation modification,which effectively changed the hydrophobicity of CB,and introduced a large number of oxygen-containing functional groups on its surface,which not only improved the charge transfer ability of the flow electrode,but also made full use of the adsorption performance of modified CB.
万方数据
维普
