Acta Phys. -Chim. Sin. ›› 2014, Vol. 30 ›› Issue (12): 2263-2271.doi: 10.3866/PKU.WHXB201410141

• ELECTROCHEMISTRY AND NEW ENERGY • Previous Articles     Next Articles

Functionalized Graphene/Activated Carbon Composite Electrodes for Asymmetric Capacitive Deionization

LU Miao1, LIU Jian-Yun1, CHENG Jian1, WANG Shi-Ping1, YANG Jian-Mao2   

  1. 1. State Enviromental Protection Engineering Center for Pollution Treament and Control in Textile Industry, School of Environmental Science and Engineering, Donghua University, Shanghai 201620, P. R. China;
    2. Analysis and Test Center, Donghua University, Shanghai 201620, P. R. China
  • Received:2014-06-23 Revised:2014-10-10 Published:2014-11-27
  • Contact: LIU Jian-Yun E-mail:jianyun.liu@dhu.edu.cn
  • Supported by:

    The project was supported by the National Natural Science Foundation of China (21476047, 21105009), Foundation of State Key Laboratory of Electroanalytical Chemistry, China (SKLEAC201205), and Fundamental Research Funds for the Central Universities, China (2232012A3-05).

Abstract:

Aminated graphene (GP-NH2) was fabricated via the modification of graphite oxide (GO) with 3-aminopropyltriethoxysilane (AMPTS), and the covalent grafting of the amine functional groups was confirmed using Fourier transform infrared (FTIR) spectroscopy and energy-dispersive X-ray (EDX) spectroscopy. The aminated graphene (GP-NH2)/activated carbon (AC) composite electrode (GP-NH2/AC) was prepared, using the GP-NH2 as an additive. An AC||GP-NH2/AC asymmetric capacitor for capacitor deionization was then assembled using the GP-NH2/AC electrode as the positive electrode and AC as the negative electrode. A salt removal of 7.63 mg·g-1 was achieved using the AC||GP-NH2/AC capacitor, and current efficiency was increased to 77.6%. AGP-SO3H/AC electrode was then prepared by mixing AC with sulfonated GP. With GP-NH2/AC as the positive electrode, and GP-SO3H/AC as the negative electrode, a GP-SO3H/AC||GP-NH2/AC asymmetric capacitor was assembled for capacitive deionization. An average desalting rate of 0.99 mg·g-1·min-1 was achieved, almost five times higher than that achieved using an AC||AC symmetric capacitor. The chargedischarge rate showed a 30% increase. The existence of the intrinsic charge on the electrode surface greatly inhibited the migration of counter ions, so that the current efficiency was significantly enhanced (to 92.8%) in comparison with the value achieved using an AC||AC capacitor (40%). These results demonstrated that the functionalized graphene in the AC electrode not only enhanced the conductivity, but also controlled the selective adsorption of ions, thereby significantly improving the deionization performance.

Key words: Aminated graphene, Sulfonated graphene, Asymmetric capacitor, Capacitive deionization

MSC2000: 

  • O646