A positive-negative alternate adsorption effect for capacitive deionization in nano-porous carbon aerogel electrodes to enhance desalination capacity

作者：Zhang, Chen; Wang, Xiaodong^*; Wang, Hongqiang; Wu, Xueling; Shen, Jun^*

来源：Desalination, 2019, 458: 45-53.

DOI：10.1016/j.desal.2019.01.023

• Carbon aerogel
• Capacitive deionization
• Electrosorption
• Positive-negative alternate adsorption (PNAA)

Carbon aerogels (CM) with different microstructure were prepared via ambient pressure drying for capacitive deionization (CDI) of NaCI solution. The activated CM exhibit a hierarchical porous structure, whose micro-, meso- and macropore size distribution can be varied with the molar ratio of resorcinol to catalyst (R/C). Desalination experiments illustrate that CA electrode with R/C of 200 shows the maximum salt adsorption capacity (SAC) of 10.34 mg/g at a working voltage of 1.5 V. It is found that electrosorption capacity of CA electrodes dose not only depend on the micro-porosity for large surface area but also the mesopores who provide transport channels. A positive-negative alternate adsorption (PNAA) method by alternating the polarity of voltage applied on the electrodes was developed to enhance the desalination capacity. The ultimate SAC of CA electrode with R/C of 200 is 25.45 mg/g, which is more than twice of the adsorption amount for the single adsorption. This method makes full use of the pores of the CAs and provides a further enhancing capacity for CA CDI.

• 出版日期2019-5-15
• 单位同济大学