Membrane-Free Hybrid Capacitive Deionization System Based on Redox Reaction for High-Efficiency NaCl Removal

Capacitive deionization (CDI) is a promising technology for desalination due to its advantages of low driven energy and environmental friendliness. However, the ion removal capacity (IRC) of CDI is insufficient for practical application because such a capacity is limited by the available surface are...

Full description

Saved in:
Bibliographic Details
Published in:Environmental science & technology 2019-06, Vol.53 (11), p.6292-6301
Main Authors: Wang, Shiyong, Wang, Gang, Wu, Tingting, Li, Changping, Wang, Yuwei, Pan, Xin, Zhan, Fei, Zhang, Yunqi, Wang, Shuaifeng, Qiu, Jieshan
Format: Article
Language:English
Subjects:
Adsorption
Carbon
Deionization
Desalination
Electrodes
Hybrid systems
Ion exchange
Low cost
Manganese dioxide
Membranes
Sodium
Sodium chloride
Surface chemistry
Technology
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Capacitive deionization (CDI) is a promising technology for desalination due to its advantages of low driven energy and environmental friendliness. However, the ion removal capacity (IRC) of CDI is insufficient for practical application because such a capacity is limited by the available surface area of the carbon electrode for ion absorption. Thus, the development of a novel desalination technology with high IRC and low cost is vital. Here, a membrane-free hybrid capacitive deionization system (HCDI) with hollow carbon@MnO2 (HC@MnO2) to capture sodium via redox reaction and hollow carbon sphere with net positive surface charges (PHC) for chloride adsorption is introduced. The as-obtained HC@MnO2 with unique structure and high conductivity can improve the utilization of MnO2 pseudocapacitive electrodes. Meanwhile, the PHC can selectively adsorb Cl– and prevent the adsorption of Na+ due to electrostatic repulsion. As expected, the membrane-free HCDI system demonstrates excellent desalination performance. The system’s IRC and maximum removal rate are 30.7 mg g–1 and 7.8 mg g–1 min–1, respectively. Moreover, the proposed system has a low cost because of the absence of expensive ion exchange membranes (IEM), which is suitable for practical application. The excellent performance of this HCDI makes it a promising desalination technology for future use.
ISSN:0013-936X
1520-5851
DOI:10.1021/acs.est.9b00662