Enhanced Water Desalination by Increasing the Electroconductivity of Carbon Powders for High-Performance Flow-Electrode Capacitive Deionization

Journal Article · Mon Dec 10 04:00:00 EST 2018 · ACS Sustainable Chemistry & Engineering

DOI:https://doi.org/10.1021/acssuschemeng.8b04746· OSTI ID:1489554

Tang, Kexin ^[1]; Yiacoumi, Sotira ^[2]; Li, Yuping ^[3]; Tsouris, Costas ^[4]

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1. Georgia Inst. of Technology, Atlanta, GA (United States). School of Civil and Environmental Engineering; Chinese Academy of Sciences (CAS), Beijing (China). Inst. of Process Engineering, Division of Environment Technology and Engineering, Beijing Engineering Research Center of Process Pollution Control; Tianjin Univ., Tianjin (China). School of Chemical Engineering and Technology, National Engineering Research Center for Distillation Technology
2. Georgia Inst. of Technology, Atlanta, GA (United States). School of Civil and Environmental Engineering
3. Chinese Academy of Sciences (CAS), Beijing (China). Inst. of Process Engineering, Division of Environment Technology and Engineering, Beijing Engineering Research Center of Process Pollution Control
4. Georgia Inst. of Technology, Atlanta, GA (United States). School of Civil and Environmental Engineering; Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

Flow-electrode capacitive deionization (FCDI) can be improved via enhanced charge transfer by increasing the flow-electrode (FE) conductivity. Since water is the main component of FE (>70%), the key to improving the electroconductivity lies in the properties of carbon materials. In this work, three types of carbon powders, i.e., activated carbon (AC), mesoporous carbon, and carbon nanotubes (CNTs), were employed in FEs to investigate the influence of powder properties on the FCDI performance. The morphology and structure of powders and electrochemical behavior and rheology of FEs were investigated to reveal the relationship between FE properties and desalination performance. Results show that, due to their unique electrosorption behavior, excellent conductivity, and enhanced conductivity through a bridging effect, CNT-based FE (carbon loading: 3 wt %) achieved the fastest (8.3 mg s–1 m–2) and the most stable desalination (charge efficiency: 93.3%). A faster desalination (13.2 mg s–1 m–2), due to significantly improved electroconductivity (13.2 times) with only a slight viscosity increase (1.1 times), was achieved by adding CNTs into 6.91 wt % AC-based FE for a 7.41 wt % total carbon concentration. This study highlights the importance of the intrinsic properties of carbon materials, especially electroconductivity, in promoting FCDI desalination performance.

• Research Organization: Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• Grant/Contract Number: AC05-00OR22725
• OSTI ID: 1489554
• Journal Information: ACS Sustainable Chemistry & Engineering, Journal Name: ACS Sustainable Chemistry & Engineering Journal Issue: 1 Vol. 7; ISSN 2168-0485
• Publisher: American Chemical Society (ACS)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY