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He Z, Miller CJ, Zhu Y, Wang Y, Fletcher J, Waite TD. Membrane capacitive deionization (MCDI): A flexible and tunable technology for customized water softening. WATER RESEARCH 2024; 259:121871. [PMID: 38852388 DOI: 10.1016/j.watres.2024.121871] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Revised: 05/20/2024] [Accepted: 06/02/2024] [Indexed: 06/11/2024]
Abstract
There is a growing demand for water treatment systems for which the quality of feedwater in and product water out are not necessarily fixed with "tunable" technologies essential in many instances to satisfy the unique requirements of particular end-users. For example, in household applications, the optimal water hardness differs for particular end uses of the supplied product (such as water for potable purposes, water for hydration, or water for coffee or tea brewing) with the inclusion of specific minerals enhancing the suitability of the product in each case. However, conventional softening technologies are not dynamically flexible or tunable and, typically, simply remove all hardness ions from the feedwater. Membrane capacitive deionization (MCDI) can potentially fill this gap with its process flexibility and tunability achieved by fine tuning different operational parameters. In this article, we demonstrate that constant-current MCDI can be operated flexibly by increasing or decreasing the current and flow rate simultaneously to achieve the same desalination performance but different productivity whilst maintaining high water recovery. This characteristic can be used to operate MCDI in an energy-efficient manner to produce treated water more slowly at times of normal demand but more rapidly at times of peak demand. We also highlight the "tunability" of MCDI enabling the control of effluent hardness over different desired ranges by correlating the rates of hardness and conductivity removal using a power function model. Using this model, it is possible to either i) soften water to the same hardness level regardless of the fluctuation in hardness of feed waters, or ii) precisely control the effluent hardness at different levels to avoid excessive or insufficient hardness removal.
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Affiliation(s)
- Zhizhao He
- UNSW Centre for Transformational Environmental Technologies, Yixing, Jiangsu Province 214206, PR China; School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia
| | - Christopher J Miller
- School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia
| | - Yunyi Zhu
- UNSW Centre for Transformational Environmental Technologies, Yixing, Jiangsu Province 214206, PR China; School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia
| | - Yuan Wang
- UNSW Centre for Transformational Environmental Technologies, Yixing, Jiangsu Province 214206, PR China; School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia
| | - John Fletcher
- School of Electrical Engineering and Telecommunications, UNSW Sydney, Sydney 2052, Australia
| | - T David Waite
- UNSW Centre for Transformational Environmental Technologies, Yixing, Jiangsu Province 214206, PR China; School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia.
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2
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Sulfonated polymer coating enhances selective removal of calcium in membrane capacitive deionization. J Memb Sci 2022. [DOI: 10.1016/j.memsci.2022.120974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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3
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Arnold S, Wang L, Presser V. Dual-Use of Seawater Batteries for Energy Storage and Water Desalination. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2107913. [PMID: 36045423 DOI: 10.1002/smll.202107913] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 07/17/2022] [Indexed: 06/15/2023]
Abstract
Seawater batteries are unique energy storage systems for sustainable renewable energy storage by directly utilizing seawater as a source for converting electrical energy and chemical energy. This technology is a sustainable and cost-effective alternative to lithium-ion batteries, benefitting from seawater-abundant sodium as the charge-transfer ions. Research has significantly improved and revised the performance of this type of battery over the last few years. However, fundamental limitations of the technology remain to be overcome in future studies to make this method even more viable. Disadvantages include degradation of the anode materials or limited membrane stability in aqueous saltwater resulting in low electrochemical performance and low Coulombic efficiency. The use of seawater batteries exceeds the application for energy storage. The electrochemical immobilization of ions intrinsic to the operation of seawater batteries is also an effective mechanism for direct seawater desalination. The high charge/discharge efficiency and energy recovery make seawater batteries an attractive water remediation technology. Here, the seawater battery components and the parameters used to evaluate their energy storage and water desalination performances are reviewed. Approaches to overcoming stability issues and low voltage efficiency are also introduced. Finally, an overview of potential applications, particularly in desalination technology, is provided.
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Affiliation(s)
- Stefanie Arnold
- INM - Leibniz Institute for New Materials, Campus D22, 66123, Saarbrücken, Germany
- Department of Materials Science and Engineering, Saarland University, Campus D22, 66123, Saarbrücken, Germany
| | - Lei Wang
- INM - Leibniz Institute for New Materials, Campus D22, 66123, Saarbrücken, Germany
- Department of Materials Science and Engineering, Saarland University, Campus D22, 66123, Saarbrücken, Germany
| | - Volker Presser
- INM - Leibniz Institute for New Materials, Campus D22, 66123, Saarbrücken, Germany
- Department of Materials Science and Engineering, Saarland University, Campus D22, 66123, Saarbrücken, Germany
- Saarene - Saarland Center for Energy Materials and Sustainability, Campus C42, 66123, Saarbrücken, Germany
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4
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Jiang Y, Jin L, Wei D, Alhassan SI, Wang H, Chai L. Energy Consumption in Capacitive Deionization for Desalination: A Review. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:10599. [PMID: 36078322 PMCID: PMC9517846 DOI: 10.3390/ijerph191710599] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 08/21/2022] [Accepted: 08/22/2022] [Indexed: 06/15/2023]
Abstract
Capacitive deionization (CDI) is an emerging eco-friendly desalination technology with mild operation conditions. However, the energy consumption of CDI has not yet been comprehensively summarized, which is closely related to the economic cost. Hence, this study aims to review the energy consumption performances and mechanisms in the literature of CDI, and to reveal a future direction for optimizing the consumed energy. The energy consumption of CDI could be influenced by a variety of internal and external factors. Ion-exchange membrane incorporation, flow-by configuration, constant current charging mode, lower electric field intensity and flowrate, electrode material with a semi-selective surface or high wettability, and redox electrolyte are the preferred elements for low energy consumption. In addition, the consumed energy in CDI could be reduced to be even lower by energy regeneration. By combining the favorable factors, the optimization of energy consumption (down to 0.0089 Wh·gNaCl-1) could be achieved. As redox flow desalination has the benefits of a high energy efficiency and long lifespan (~20,000 cycles), together with the incorporation of energy recovery (over 80%), a robust future tendency of energy-efficient CDI desalination is expected.
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Affiliation(s)
- Yuxin Jiang
- School of Metallurgy and Environment, Central South University, Changsha 410083, China
| | - Linfeng Jin
- School of Metallurgy and Environment, Central South University, Changsha 410083, China
| | - Dun Wei
- School of Metallurgy and Environment, Central South University, Changsha 410083, China
| | - Sikpaam Issaka Alhassan
- Chemical and Environmental Engineering Department, College of Engineering, University of Arizona, Tucson, AZ 85721, USA
| | - Haiying Wang
- School of Metallurgy and Environment, Central South University, Changsha 410083, China
- Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Changsha 410083, China
- Water Pollution Control Technology Key Lab of Hunan Province, Changsha 410083, China
| | - Liyuan Chai
- School of Metallurgy and Environment, Central South University, Changsha 410083, China
- Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Changsha 410083, China
- Water Pollution Control Technology Key Lab of Hunan Province, Changsha 410083, China
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5
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Alkhadra M, Su X, Suss ME, Tian H, Guyes EN, Shocron AN, Conforti KM, de Souza JP, Kim N, Tedesco M, Khoiruddin K, Wenten IG, Santiago JG, Hatton TA, Bazant MZ. Electrochemical Methods for Water Purification, Ion Separations, and Energy Conversion. Chem Rev 2022; 122:13547-13635. [PMID: 35904408 PMCID: PMC9413246 DOI: 10.1021/acs.chemrev.1c00396] [Citation(s) in RCA: 46] [Impact Index Per Article: 23.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Agricultural development, extensive industrialization, and rapid growth of the global population have inadvertently been accompanied by environmental pollution. Water pollution is exacerbated by the decreasing ability of traditional treatment methods to comply with tightening environmental standards. This review provides a comprehensive description of the principles and applications of electrochemical methods for water purification, ion separations, and energy conversion. Electrochemical methods have attractive features such as compact size, chemical selectivity, broad applicability, and reduced generation of secondary waste. Perhaps the greatest advantage of electrochemical methods, however, is that they remove contaminants directly from the water, while other technologies extract the water from the contaminants, which enables efficient removal of trace pollutants. The review begins with an overview of conventional electrochemical methods, which drive chemical or physical transformations via Faradaic reactions at electrodes, and proceeds to a detailed examination of the two primary mechanisms by which contaminants are separated in nondestructive electrochemical processes, namely electrokinetics and electrosorption. In these sections, special attention is given to emerging methods, such as shock electrodialysis and Faradaic electrosorption. Given the importance of generating clean, renewable energy, which may sometimes be combined with water purification, the review also discusses inverse methods of electrochemical energy conversion based on reverse electrosorption, electrowetting, and electrokinetic phenomena. The review concludes with a discussion of technology comparisons, remaining challenges, and potential innovations for the field such as process intensification and technoeconomic optimization.
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Affiliation(s)
- Mohammad
A. Alkhadra
- Department
of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, Massachusetts 02139, United States
| | - Xiao Su
- Department
of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Matthew E. Suss
- Faculty
of Mechanical Engineering, Technion—Israel
Institute of Technology, Haifa 3200003, Israel,Wolfson
Department of Chemical Engineering, Technion—Israel
Institute of Technology, Haifa 3200003, Israel,Nancy
and Stephen Grand Technion Energy Program, Technion—Israel Institute of Technology, Haifa 3200003, Israel
| | - Huanhuan Tian
- Department
of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, Massachusetts 02139, United States
| | - Eric N. Guyes
- Faculty
of Mechanical Engineering, Technion—Israel
Institute of Technology, Haifa 3200003, Israel
| | - Amit N. Shocron
- Faculty
of Mechanical Engineering, Technion—Israel
Institute of Technology, Haifa 3200003, Israel
| | - Kameron M. Conforti
- Department
of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, Massachusetts 02139, United States
| | - J. Pedro de Souza
- Department
of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, Massachusetts 02139, United States
| | - Nayeong Kim
- Department
of Chemical and Biomolecular Engineering, University of Illinois at Urbana−Champaign, Urbana, Illinois 61801, United States
| | - Michele Tedesco
- European
Centre of Excellence for Sustainable Water Technology, Wetsus, Oostergoweg 9, 8911 MA Leeuwarden, The Netherlands
| | - Khoiruddin Khoiruddin
- Department
of Chemical Engineering, Institut Teknologi
Bandung, Jl. Ganesha no. 10, Bandung, 40132, Indonesia,Research
Center for Nanosciences and Nanotechnology, Institut Teknologi Bandung, Jl. Ganesha no. 10, Bandung 40132, Indonesia
| | - I Gede Wenten
- Department
of Chemical Engineering, Institut Teknologi
Bandung, Jl. Ganesha no. 10, Bandung, 40132, Indonesia,Research
Center for Nanosciences and Nanotechnology, Institut Teknologi Bandung, Jl. Ganesha no. 10, Bandung 40132, Indonesia
| | - Juan G. Santiago
- Department
of Mechanical Engineering, Stanford University, Stanford, California 94305, United States
| | - T. Alan Hatton
- Department
of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, Massachusetts 02139, United States
| | - Martin Z. Bazant
- Department
of Chemical Engineering, Massachusetts Institute
of Technology, Cambridge, Massachusetts 02139, United States,Department
of Mathematics, Massachusetts Institute
of Technology, Cambridge, Massachusetts 02139, United States,
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6
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Liu Y, Du X, Wang Z, Wang L, Liu Z, Shi W, Zheng R, Dou X, Zhu H, Yuan X. Layered double hydroxide coated electrospun carbon nanofibers as the chloride capturing electrode for ultrafast electrochemical deionization. J Colloid Interface Sci 2021; 609:289-296. [PMID: 34896829 DOI: 10.1016/j.jcis.2021.12.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 11/25/2021] [Accepted: 12/01/2021] [Indexed: 10/19/2022]
Abstract
Slow desalination kinetics and poor durability of the electrodes are two key limitations of electrochemical deionization (EDI) that are considered to be the next generation of capacitive desalination (CDI). Herein, we report the design of a high-efficiency chloride removal electrode material for accelerating the desalination kinetics and concurrently improving the durability of EDI, which is based on coating NiMn-Cl layered double hydroxides (LDHs) on the surface of electrospun carbon nanofibers (CNFs@LDHs). The salient features of the as-developed CNFs@LDHs are that applying layer-structured LDHs with abundant redox-active sites to accelerate the pseudo-capacitive ion storage via fast ion intercalation/deintercalation, and leveraging the rigid CNF backbone to strengthen its durability by preventing the potential aggregation of LDHs. As expected, the CNFs@LDH based EDI system displays an ultrafast desalination rate of 0.51 mg g-1 s-1 and outstanding long-term stability (only 10.66 % desalination capacity reduction after 35 cycles), which is achieved without sacrificing its excellent desalination capacity (72.04 mg g-1). This work could be inspirational for the future design of ultrafast yet durable EDI approaching industrial desalination applications.
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Affiliation(s)
- Yong Liu
- School of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
| | - Xin Du
- School of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
| | - Ziping Wang
- Shandong Peninsula Engineering Research Center of Comprehensive Brine Utilization, Weifang University of Science and Technology, Weifang, Shandong 262700, China
| | - Lihao Wang
- School of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
| | - Zizhen Liu
- School of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
| | - Wenxue Shi
- School of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
| | - Runzhe Zheng
- School of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
| | - Xinyue Dou
- School of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
| | - Haiguang Zhu
- School of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
| | - Xun Yuan
- School of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
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7
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Wang K, Liu Y, Ding Z, Chen Z, Zhu G, Xu X, Lu T, Pan L. Controlled synthesis of NaTi2(PO4)3/Carbon composite derived from Metal-organic-frameworks as highly-efficient electrodes for hybrid capacitive deionization. Sep Purif Technol 2021. [DOI: 10.1016/j.seppur.2021.119565] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
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8
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Wang K, Du X, Liu Z, Geng B, Shi W, Liu Y, Dou X, Zhu H, Pan L, Yuan X. Bismuth oxychloride nanostructure coated carbon sponge as flow-through electrode for highly efficient rocking-chair capacitive deionization. J Colloid Interface Sci 2021; 608:2752-2759. [PMID: 34785052 DOI: 10.1016/j.jcis.2021.11.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 11/01/2021] [Indexed: 10/19/2022]
Abstract
Rocking-chair capacitive deionization (RCDI), as the next generation technique of capacitive deionization, has thrived to be one of the most promising strategies in the desalination community, yet was hindered mostly by its relatively low desalination rate and stability. Motivated by the goal of simultaneously enhancing the desalination rate and structural stability of the electrode, this paper reports an anion-driven flow-through RCDI (AFT-RCDI) system equipped with BiOCl nanostructure coated carbon sponge (CS@BiOCl for short; its backbone is derived from commercially available melamine foam with minimum capital cost) as the flow-through electrode. Owning to the rational design of the composite electrode material with minimum charge transfer resistance and ultrahigh structure stability as well as the superior flow-through cell architecture, the AFT-RCDI displays excellent desalination performance (desalination capacity up to 107.33 mg g-1; desalination rate up to 0.53 mg g-1s-1) with superior long-term stability (91.75% desalination capacity remained after 30 cycles). This work provides a new thought of coupling anion capturing electrode with flow-through cell architecture and employing a low-cost CS@BiOCl electrode with commercially available backbone material, which could shed light on the further development of low-cost electrochemical desalination systems.
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Affiliation(s)
- Kai Wang
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
| | - Xin Du
- School of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
| | - Zizhen Liu
- School of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
| | - Bo Geng
- School of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
| | - Wenxue Shi
- School of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
| | - Yong Liu
- School of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China.
| | - Xinyue Dou
- School of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
| | - Haiguang Zhu
- School of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
| | - Likun Pan
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China
| | - Xun Yuan
- School of Materials Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
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9
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Li Y, Wang R, Shi S, Cao H, Yip NY, Lin S. Bipolar Membrane Electrodialysis for Ammonia Recovery from Synthetic Urine: Experiments, Modeling, and Performance Analysis. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2021; 55:14886-14896. [PMID: 34637289 DOI: 10.1021/acs.est.1c05316] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Recovering nitrogen from source-separated urine is an important part of the sustainable nitrogen management. A novel bipolar membrane electrodialysis with membrane contactor (BMED-MC) process is demonstrated here for efficient recovery of ammonia from synthetic source-separated urine (∼3772 mg N L-1). In a BMED-MC process, electrically driven water dissociation in a bipolar membrane simultaneously increases the pH of the urine stream and produces an acid stream for ammonia stripping. With the increased pH of urine, ammonia transports across the gas-permeable membrane in the membrane contactor and is recovered by the acid stream as ammonium sulfate that can be directly used as fertilizer. Our results obtained using batch experiments demonstrate that the BMED-MC process can achieve 90% recovery. The average ammonia flux and the specific energy consumption can be regulated by varying the current density. At a current density of 20 mA cm-2, the energy required to achieve a 67.5% ammonia recovery in a 7 h batch mode is 92.8 MJ kg-1 N for a bench-scale system with one membrane stack and can approach 25.8 MJ kg-1 N for large-scale systems with multiple membrane stacks, with an average ammonia flux of 2.2 mol m-2 h-1. Modeling results show that a continuous BMED-MC process can achieve a 90% ammonia recovery with a lower energy consumption (i.e., 12.5 MJ kg-1 N). BMED-MC shows significant potential for ammonia recovery from source-separated urine as it is relatively energy-efficient and requires no external acid solution.
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Affiliation(s)
- Yujiao Li
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, Tennessee 37235-1831, United States
- Beijing Engineering Research Center of Process Pollution Control, Institute of Process Engineering, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ruoyu Wang
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, Tennessee 37235-1831, United States
| | - Shaoyuan Shi
- Beijing Engineering Research Center of Process Pollution Control, Institute of Process Engineering, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hongbin Cao
- Beijing Engineering Research Center of Process Pollution Control, Institute of Process Engineering, Innovation Academy for Green Manufacture, Chinese Academy of Sciences, Beijing 100190, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Ngai Yin Yip
- Department of Earth and Environmental Engineering, Columbia University, New York 10027-6623, United States
- Columbia Water Center, Columbia University, New York 10027-6623, United States
| | - Shihong Lin
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, Tennessee 37235-1831, United States
- Department of Chemical and Bimolecular Engineering, Vanderbilt University, Nashville, Tennessee 37235-1831, United States
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10
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11
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Liu Y, Wang K, Xu X, Eid K, Abdullah AM, Pan L, Yamauchi Y. Recent Advances in Faradic Electrochemical Deionization: System Architectures versus Electrode Materials. ACS NANO 2021; 15:13924-13942. [PMID: 34498859 DOI: 10.1021/acsnano.1c03417] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Capacitive deionization (CDI) is an energy-efficient desalination technique. However, the maximum desalination capacity of conventional carbon-based CDI systems is approximately 20 mg g-1, which is too low for practical applications. Therefore, the focus of research on CDI has shifted to the development of faradic electrochemical deionization systems using electrodes based on faradic materials which have a significantly higher ion-storage capacity than carbon-based electrodes. In addition to the common symmetrical CDI system, there has also been extensive research on innovative systems to maximize the performance of faradic electrode materials. Research has focused primarily on faradic reactions and faradic electrode materials. However, the correlation between faradic electrode materials and the various electrochemical deionization system architectures, i.e., hybrid capacitive deionization, rocking-chair capacitive deionization, and dual-ion intercalation electrochemical desalination, remains relatively unexplored. This has inhibited the design of specific faradic electrode materials based on the characteristics of individual faradic electrochemical desalination systems. In this review, we have characterized faradic electrode materials based on both their material category and the electrochemical desalination system in which they were utilized. We expect that the detailed analysis of the properties, advantages, and challenges of the individual systems will establish a fundamental correlation between CDI systems and electrode materials that will facilitate future developments in this field.
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Affiliation(s)
- Yong Liu
- School of Material Science and Engineering, Qingdao University of Science and Technology, Qingdao, Shandong 266042, China
| | - Kai Wang
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai 200062, China
| | - Xingtao Xu
- JST-ERATO Yamauchi Materials Space-Tectonics Project and International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Kamel Eid
- Gas Processing Center, College of Engineering, Qatar University, Doha 2713, Qatar
| | | | - Likun Pan
- Shanghai Key Laboratory of Magnetic Resonance, School of Physics and Electronic Science, East China Normal University, Shanghai 200062, China
| | - Yusuke Yamauchi
- JST-ERATO Yamauchi Materials Space-Tectonics Project and International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
- Australian Institute for Bioengineering and Nanotechnology (AIBN) and School of Chemical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia
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12
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Luo L, He Q, Ma Z, Yi D, Chen Y, Ma J. In situ potential measurement in a flow-electrode CDI for energy consumption estimation and system optimization. WATER RESEARCH 2021; 203:117522. [PMID: 34384947 DOI: 10.1016/j.watres.2021.117522] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Revised: 07/28/2021] [Accepted: 08/02/2021] [Indexed: 06/13/2023]
Abstract
Flow electrode capacitive deionization (FCDI) is a promising electrochemical technique for brackish water desalination; however, there are challenges in estimating the distribution of resistance and energy consumption inside a FCDI system, which hinders the optimization of the rate-limiting compartment. In this study, energy consumption of each FCDI component (e.g., flow electrodes, membranes and desalination chamber) was firstly described by using in situ potential measurement (ISPM). Results of this study showed that the energy consumption (EC) of the flow electrodes dominated under most conditions. While an increase in the carbon black content in the flow electrodes could improve the energy efficiency of the electrode component, consideration should be given to the contribution of ion exchange membranes (IEMs) and the desalination chamber to the EC. Based on the above analysis, system optimization was carried out by introducing IEMs with relatively low resistance and/or packing the desalination chamber with titanium meshes. Results showed that the voltage-driven desalination capability was increased by 39.3% with the EC reduced by 17.5% compared to the control, which overcame the tradeoff between the kinetic and energetic efficiencies. Overall, the present work facilitates our understanding of the potential drops across an FCDI system and provides insight to the optimization of system design and operation.
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Affiliation(s)
- Liang Luo
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400044, PR China.; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400044, PR China
| | - Qiang He
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400044, PR China.; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400044, PR China
| | - Zixin Ma
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400044, PR China.; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400044, PR China
| | - Duo Yi
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400044, PR China.; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400044, PR China
| | - Yi Chen
- Key Laboratory of the Three Gorges Reservoir Region's Eco-Environment, Ministry of Education, Chongqing University, Chongqing 400044, PR China.; National Centre for International Research of Low-carbon and Green Buildings, Chongqing University, Chongqing 400044, PR China..
| | - Jinxing Ma
- Key Laboratory for City Cluster Environmental Safety and Green Development of the Ministry of Education, Institute of Environmental and Ecological Engineering, Guangdong University of Technology, Guangzhou, 510006, PR China.
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Renewable Energy Powered Membrane Technology: Electrical Energy Storage Options for a Photovoltaic-Powered Brackish Water Desalination System. APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11020856] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The potential for lithium-ion (Li-ion) batteries and supercapacitors (SCs) to overcome long-term (one day) and short-term (a few minutes) solar irradiance fluctuations with high-temporal-resolution (one s) on a photovoltaic-powered reverse osmosis membrane (PV-membrane) system was investigated. Experiments were conducted using synthetic brackish water (5-g/L sodium chloride) with varied battery capacities (100, 70, 50, 40, 30 and 20 Ah) to evaluate the effect of decreasing the energy storage capacities. A comparison was made between SCs and batteries to determine system performance on a “partly cloudyday”. With fully charged batteries, clean drinking water was produced at an average specific energy consumption (SEC) of 4 kWh/m3. The daily water production improved from 663 L to 767 L (16% increase) and average electrical conductivity decreased from 310 µS/cm to 274 μS/cm (12% improvement), compared to the battery-less system. Enhanced water production occurred when the initial battery capacity was >50 Ah. On a “sunny” and “very cloudy” day with fully charged batteries, water production increased by 15% and 80%, while water quality improved by 18% and 21%, respectively. The SCs enabled a 9% increase in water production and 13% improvement in the average SEC on the “partly cloudy day” when compared to the reference system performance (without SCs).
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Liu X, Shanbhag S, Natesakhawat S, Whitacre JF, Mauter MS. Performance Loss of Activated Carbon Electrodes in Capacitive Deionization: Mechanisms and Material Property Predictors. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:15516-15526. [PMID: 33205957 DOI: 10.1021/acs.est.0c06549] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Understanding the material property origins of performance decay in carbon electrodes is critical to maximizing the longevity of capacitive deionization (CDI) systems. This study investigates the cycling stability of electrodes fabricated from six commercial and two post-processed activated carbons. We find that the capacity decay rate of electrodes in half cells is positively correlated with the specific surface area and total surface acidity of the activated carbons. We also demonstrate that half-cell cycling stability is consistent with full cell desalination performance durability. Additionally, our results suggest that increase in internal resistance and physical pore blockage resulting from extensive cycling may be important mechanisms for the specific capacitance decay of activated carbon electrodes in this study. Our findings provide crucial guidelines for selecting activated carbon electrodes for stable CDI performance over long-term operation and insight into appropriate parameters for electrode performance and longevity in models assessing the techno-economic viability of CDI. Finally, our half-cell cycling protocol also offers a method for evaluating the stability of new electrode materials without preparing large, freestanding electrodes.
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Affiliation(s)
- Xitong Liu
- Department of Civil & Environmental Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
- Department of Civil and Environmental Engineering, The George Washington University, 800 22nd Street NW, Washington, D.C. 20052, United States
| | - Sneha Shanbhag
- Department of Civil & Environmental Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Sittichai Natesakhawat
- National Energy Technology Laboratory, U.S. Department of Energy, 626 Cochrans Mill Road, P.O. Box 10940, Pittsburgh, Pennsylvania 15236, United States
- Department of Chemical and Petroleum Engineering, University of Pittsburgh, 4200 Fifth Avenue, Pittsburgh, Pennsylvania 15260, United States
| | - Jay F Whitacre
- Department of Engineering and Public Policy, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
- Department of Material Science and Engineering, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
- The Scott Institute for Energy Innovation, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Meagan S Mauter
- Department of Civil and Environmental Engineering, Stanford University, Stanford, California 94305, United States
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16
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Pan SY, Haddad AZ, Kumar A, Wang SW. Brackish water desalination using reverse osmosis and capacitive deionization at the water-energy nexus. WATER RESEARCH 2020; 183:116064. [PMID: 32745671 DOI: 10.1016/j.watres.2020.116064] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2020] [Revised: 05/30/2020] [Accepted: 06/14/2020] [Indexed: 06/11/2023]
Abstract
In this article, we present a critical review of the reported performance of reverse osmosis (RO) and capacitive deionization (CDI) for brackish water (salinity < 5.0 g/L) desalination from the aspects of engineering, energy, economy and environment. We first illustrate the criteria and the key performance indicators to evaluate the performance of brackish water desalination. We then systematically summarize technological information of RO and CDI, focusing on the effect of key parameters on desalination performance, as well as energy-water efficiency, economic costs and environmental impacts (including carbon footprint). We provide in-depth discussion on the interconnectivity between desalination and energy, and the trade-off between kinetics and energetics for RO and CDI as critical factors for comparison. We also critique the results of technical-economic assessment for RO and CDI plants in the context of large-scale deployment, with focus on lifetime-oriented consideration to total costs, balance between energy efficiency and clean water production, and pretreatment/post-treatment requirements. Finally, we illustrate the challenges and opportunities for future brackish water desalination, including hybridization for energy-efficient brackish water desalination, co-removal of specific components in brackish water, and sustainable brine management with innovative utilization. Our study reveals that both RO and CDI should play important roles in water reclamation and resource recovery from brackish water, especially for inland cities or rural regions.
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Affiliation(s)
- Shu-Yuan Pan
- Department of Bioenvironmental Systems Engineering, National Taiwan University, No. 1, Section 4, Roosevelt Road, Taipei City, 10617, Taiwan, ROC.
| | - Andrew Z Haddad
- Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Arkadeep Kumar
- Energy Technologies Area, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA
| | - Sheng-Wei Wang
- Department of Water Resources and Environmental Engineering, Tamkang University, New Taipei City, 251301, Taiwan, ROC
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Wang L, Zhang C, He C, Waite TD, Lin S. Equivalent film-electrode model for flow-electrode capacitive deionization: Experimental validation and performance analysis. WATER RESEARCH 2020; 181:115917. [PMID: 32505888 DOI: 10.1016/j.watres.2020.115917] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 04/26/2020] [Accepted: 05/03/2020] [Indexed: 06/11/2023]
Abstract
Flow electrode capacitive deionization (FCDI) is a promising configuration for capacitive deionization due to its capability of continuous operation and achieving a relatively large salinity reduction. Due to the complexity of the multi-phase flow involved in FCDI, modeling FCDI system performance has been a challenge with no predictive FCDI model thus far developed. In this study, we developed an equivalent film-electrode (EFE) model for FCDI in which the flow electrodes are approximated as moving film electrodes that behave in a manner similar to conveyor belts. The EFE-FCDI model is validated using results from a series of FCDI experiments and then applied to elucidate the spatial variations of the key properties of the FCDI system and to resolve the contributions of different aspects of the system to energy consumption. The impact of activated carbon loading in the flow electrode and the feed and effluent target concentrations on the overall FCDI performance are also discussed based on model simulation. In summary, the EFE-FCDI model enhances our understanding of the system-level behavior of FCDI systems and can be employed for optimizing FCDI design and operation.
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Affiliation(s)
- Li Wang
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN, 37235-1831, USA
| | - Changyong Zhang
- UNSW Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, New South Wales, 2052, Australia
| | - Calvin He
- UNSW Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, New South Wales, 2052, Australia
| | - T David Waite
- UNSW Water Research Centre, School of Civil and Environmental Engineering, The University of New South Wales, Sydney, New South Wales, 2052, Australia
| | - Shihong Lin
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN, 37235-1831, USA; Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN, 37235-1604, USA.
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18
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Wang R, Lin S. Thermodynamic reversible cycles of electrochemical desalination with intercalation materials in symmetric and asymmetric configurations. J Colloid Interface Sci 2020; 574:152-161. [DOI: 10.1016/j.jcis.2020.04.032] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/02/2020] [Accepted: 04/07/2020] [Indexed: 01/23/2023]
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Towards Electrochemical Water Desalination Techniques: A Review on Capacitive Deionization, Membrane Capacitive Deionization and Flow Capacitive Deionization. MEMBRANES 2020; 10:membranes10050096. [PMID: 32408502 PMCID: PMC7281590 DOI: 10.3390/membranes10050096] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 05/07/2020] [Accepted: 05/07/2020] [Indexed: 11/16/2022]
Abstract
Electrochemical water desalination has been a major research area since the 1960s with the development of capacitive deionization technique. For the latter, its modus operandi lies in temporary salt ion adsorption when a simple potential difference (1.0-1.4 V) of about 1.2 V is supplied to the system to temporarily create an electric field that drives the ions to their different polarized poles and subsequently desorb these solvated ions when potential is switched off. Capacitive deionization targets/extracts the solutes instead of the solvent and thus consumes less energy and is highly effective for brackish water. This paper reviews Capacitive Deionization (mechanism of operation, sustainability, optimization processes, and shortcomings) with extension to its counterparts (Membrane Capacitive Deionization and Flow Capacitive Deionization).
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Wang L, Liang Y, Zhang L. Enhancing Performance of Capacitive Deionization with Polyelectrolyte-Infiltrated Electrodes: Theory and Experimental Validation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:5874-5883. [PMID: 32216292 DOI: 10.1021/acs.est.9b07692] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The energy efficiency of capacitive deionization (CDI) with porous carbon electrodes is limited by the high ionic resistance of the macropores in the electrodes. In this study, we demonstrate a facile approach to improve the energy efficiency by filling the macropores with ion-conductive polyelectrolytes, which is termed polyelectrolyte-infiltrated CDI (pie-CDI or πCDI). In πCDI, the filled polyelectrolyte effectively turns the macropores into a charged ion-selective layer and thus increases the conductivity of macropores. We show experimentally that πCDI can save up to half of the energy consumption compared to membrane CDI, achieving identical desalination during the charging step. The energy consumption can be even lower if the process is operated at a smaller average salt adsorption rate. Further energy breakdown analysis based on a theoretical model confirms that the improved energy efficiency is largely attributed to the increased conductivity in the macropores.
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Affiliation(s)
- Li Wang
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, Tennessee 37235-1831, United States
| | - Yuanzhe Liang
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, Tennessee 37235-1831, United States
| | - Li Zhang
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA Leeuwarden, The Netherlands
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21
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Christie KSS, Horseman T, Lin S. Energy efficiency of membrane distillation: Simplified analysis, heat recovery, and the use of waste-heat. ENVIRONMENT INTERNATIONAL 2020; 138:105588. [PMID: 32126386 DOI: 10.1016/j.envint.2020.105588] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2019] [Revised: 02/15/2020] [Accepted: 02/16/2020] [Indexed: 06/10/2023]
Abstract
Membrane distillation (MD) is a thermal desalination process that is advantageous due to its ability to harness low-grade waste heat to separate highly saline feedstock. However, like any thermal desalination process, the energy efficiency depends on the ability to recover latent heat from condensation in the distillate. In direct contact MD (DCMD), this can be achieved by integrating a heat exchanger (HX) to recover latent heat stored in the distillate stream to preheat the incoming feed stream. Based on the principle of equal heat capacity flows, we derive a simple and intuitive expression for the optimal flow rate ratio between the feed and distillate streams to best recover this latent. Following the principle of energy balance, we derive simple expressions for the specific thermal energy consumption (SECth) and gained output ratio (GOR) of DCMD with and without a coupled HX for latent heat recovery, revealing an intuitive critical condition that indicates whether DCMD should or should not be coupled with HX. As MD is attractive for its ability to use low-grade waste heat as a heat source, we also evaluate the energy efficiency of DCMD powered by a waste heat stream. A waste heat stream differs fundamentally from a conventional constant-temperature heat source in that the temperature of the waste heat stream decreases as heat is extracted from it. We discuss the implication of this fundamental difference on energy efficiency and how we should analyze the energy efficiency of DCMD powered by waste heat streams. A new metric, namely specific yield, is proposed to quantify the performance of DCMD powered by waste heat stream. Our analysis suggests that, for a single-stage DCMD powered by a waste heat stream, whether implementing latent heat recovery or not only affects conventional metrics for energy efficiency (e.g. SECth and GOR) but not the specific yield. Overall, this analysis presents an intuitive and important framework for evaluating and optimizing energy efficiency in DCMD.
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Affiliation(s)
- Kofi S S Christie
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN 37235, United States
| | - Thomas Horseman
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235, United States
| | - Shihong Lin
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN 37235, United States; Department of Chemical and Biomolecular Engineering, Vanderbilt University, Nashville, TN 37235, United States.
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22
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Pothanamkandathil V, Fortunato J, Gorski CA. Electrochemical Desalination Using Intercalating Electrode Materials: A Comparison of Energy Demands. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:3653-3662. [PMID: 32048848 DOI: 10.1021/acs.est.9b07311] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
One approach for desalinating brackish water is to use electrode materials that electrochemically remove salt ions from water. Recent studies found that sodium-intercalating electrode materials (i.e., materials that reversibly insert Na+ ions into their structures) have higher specific salt storage capacities (mgsalt/gmaterial) than carbon-based electrode materials over smaller or similar voltage windows. These observations have led to the hypothesis that energy demands of electrochemical desalination systems can be decreased by replacing carbon-based electrodes with intercalating electrodes. To test this hypothesis and directly compare intercalation materials, we examined nine electrode materials thought to be capable of sodium intercalation in an electrochemical flow cell with respect to volumetric energy demands (W·h·L-1) and thermodynamic efficiencies as a function of productivity (i.e., the rate of water desalination, L·m-2·h-1). We also examined how the materials' charge-storage capacities changed over 50 cycles. Intercalation materials desalinated brackish water more efficiently than carbon-based electrodes when we assumed that no energy recovery occurred (i.e., no energy was recovered when the cell produced electrical power during cycling) and exhibited similar efficiencies when we assumed complete energy recovery. Nickel hexacyanoferrate exhibited the lowest energy demand among all of the materials and exhibited the highest stability over 50 cycles.
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Affiliation(s)
- Vineeth Pothanamkandathil
- Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Jenelle Fortunato
- Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Christopher A Gorski
- Department of Civil and Environmental Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
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23
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Wang T, Zhang C, Bai L, Xie B, Gan Z, Xing J, Li G, Liang H. Scaling behavior of iron in capacitive deionization (CDI) system. WATER RESEARCH 2020; 171:115370. [PMID: 31864131 DOI: 10.1016/j.watres.2019.115370] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2019] [Revised: 11/22/2019] [Accepted: 12/02/2019] [Indexed: 06/10/2023]
Abstract
This study investigated the fouling and scaling behaviors in a capacitive deionization (CDI) system in the presence of iron and natural organic matter (NOM). It was found that the salt adsorption capacity (SAC) significantly decreased when treating Fe-containing brackish water, with higher Fe concentrations leading to severer SAC reduction. Raman spectroscopy, X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) analysis demonstrated that Fe2O3 appeared to be the predominant foulant attached on the electrode surface, which was difficult to be removed via backwashing, indicating the irreversible property of the foulant. Further characterizations (e.g., N2 sorption-desorption isotherms, electrochemical impedance spectroscopy and cyclic voltammetry) revealed that the CDI electrodes suffered from obvious deterioration such as specific surface area loss, resistance increase and capacitance decline with the occurrence of Fe scaling. While the presence of NOM alleviated the Fe scaling through NOM-Fe complexing effects, NOM itself was found to have negative impacts on CDI desalination performance due to their strong interactions with the carbon electrodes.
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Affiliation(s)
- Tianyu Wang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China.
| | - Changyong Zhang
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Langming Bai
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China.
| | - Binghan Xie
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China.
| | - Zhendong Gan
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China.
| | - Jiajian Xing
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China.
| | - Guibai Li
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China.
| | - Heng Liang
- State Key Laboratory of Urban Water Resource and Environment, School of Environment, Harbin Institute of Technology, Harbin, 150090, PR China.
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Tang YH, Liu SH, Tsang DCW. Microwave-assisted production of CO 2-activated biochar from sugarcane bagasse for electrochemical desalination. JOURNAL OF HAZARDOUS MATERIALS 2020; 383:121192. [PMID: 31539661 DOI: 10.1016/j.jhazmat.2019.121192] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 09/08/2019] [Accepted: 09/08/2019] [Indexed: 06/10/2023]
Abstract
A high-performance carbon electrode is desirable for promoting electrochemical desalination efficiency in the membrane capacitive deionization (MCDI). Sugarcane bagasse (food waste) was employed in this study to prepare hierarchically porous biochars by microwave-assisted carbonization and activation with potassium hydroxide in N2 or CO2 atmosphere under varying flow rates (100-600 cm3 min-1). The sugarcane bagasse-derived biochars activated under CO2 flow of 300 cm3 min-1 (denoted as SBB-CO2-300) possessed the ratio of mesopores to total pore volume (Vmeso/Vtotal) of 56.7% with a specific surface area of 1019 m2 g-1. The electrochemical behavior of SBB-CO2-300 was demonstrated by a surpassing specific capacitance of 208 F g-1 at 5 mV s-1 by means of cyclic voltammetry. The desalination tests using a batch-mode MCDI at 1.2 V in a 5 mM NaCl solution indicated that the SBB-CO2-300 electrode exhibited an excellent electrosorption capacity of 28.9 mg g-1. The improvement in the electrochemical deionization performance of SBB-CO2-300 was attributed to the superior Vmeso/Vtotal ratio, high surface area, excellent capacitance behavior, and hierarchical pore structure. The biowaste-derived biochars prepared via facile microwave-assisted carbonization and CO2 activation route can provide a sustainable and high-efficiency carbon electrode for electrochemical deionization of brackish water.
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Affiliation(s)
- Yi-Hsin Tang
- Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan
| | - Shou-Heng Liu
- Department of Environmental Engineering, National Cheng Kung University, Tainan 70101, Taiwan.
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
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25
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Lin S. Energy Efficiency of Desalination: Fundamental Insights from Intuitive Interpretation. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2020; 54:76-84. [PMID: 31816233 DOI: 10.1021/acs.est.9b04788] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Desalination has become an essential toolset to combat the worsening water stress resulting from population and industrial growth and exacerbated by climate change. Various technologies have been developed to desalinate feedwater with a wide spectrum of salinity. While energy consumption is an important consideration in many desalination studies, it is challenging to make (intuitive) sense of energy efficiency due to the different mechanisms of various desalination processes and the very different separations achieved. This perspective aims to provide an intuitive, thermodynamics-based interpretation of energy efficiency by illustrating how energy consumption breaks down into minimum energy of separation and the irreversible energy dissipation. The energy efficiencies of different desalination processes are summarized and rationalized based on their working mechanisms. Notably, a new concept called the minimum mean voltage is proposed as a convenient tool to evaluate the energy efficiency of electrochemical desalination processes. Lastly, the intrinsic trade-off between energy efficiency and desalination rate and the relevance of energy efficiency in different desalination applications are discussed.
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Tan C, He C, Fletcher J, Waite TD. Energy recovery in pilot scale membrane CDI treatment of brackish waters. WATER RESEARCH 2020; 168:115146. [PMID: 31627136 DOI: 10.1016/j.watres.2019.115146] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 09/15/2019] [Accepted: 09/30/2019] [Indexed: 06/10/2023]
Abstract
An energy recovery technique using a high-current bi-directional dc-dc converter for membrane capacitive de-ionization (mCDI) of brackish waters is described and it's performance assessed in a pilot-scale prototype. The energy recovery system is shown to reduce the energy consumption of the pilot-scale mCDI unit, powered by photovoltaics and with battery storage, by between 30 and 40%. Use of a stopped flow process also enables water recovery of up to 87%. The contributions to energy consumption in the system are quantified with the insights gained from this analysis enabling the selection of an optimum voltage range for desorption termination that maximizes the daily recovered energy. The experimental results demonstrate that energy usage by the mCDI process of lower than 0.4 kWh/m3 is achievable with almost 40% of the energy supplied by the batteries recovered.
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Affiliation(s)
- Cheng Tan
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Calvin He
- School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - John Fletcher
- School of Electrical Engineering and Telecommunications, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - T David Waite
- School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
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27
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Ma J, Ma J, Zhang C, Song J, Dong W, Waite TD. Flow-electrode capacitive deionization (FCDI) scale-up using a membrane stack configuration. WATER RESEARCH 2020; 168:115186. [PMID: 31655437 DOI: 10.1016/j.watres.2019.115186] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 09/05/2019] [Accepted: 10/11/2019] [Indexed: 06/10/2023]
Abstract
Flow-electrode capacitive deionization (FCDI) is an attractive variant of CDI with distinct advantages over fixed electrode CDI including the capability for seawater desalination, high flow efficiency and easy management of the electrodes. Challenges exist however in increasing treatment capacity with this attempted here through use of a membrane stack configuration. By comparison of standardised metrics (in particular, average salt removal rate (ASRR), energy normalized removed salt (ENRS) and productivity), results show that that an FCDI system with two pairs of ion exchange membranes had the highest efficiency in desalting a brackish influent (1000 mg L-1) to potable levels (∼150 mg L-1) at higher ASRR and ENRS. Further increase in the number of membrane pairs resulted in a decrease in current efficiency, likely as a result of the dominance of electrodialysis. Results of this study provide proof of concept that (semi-)continuous desalination can be achieved in FCDI at high energy efficiency (13.8%-20.2%) and productivity (> 100 L m-2 h-1) and, importantly, provide insight into possible approaches to scaling up FCDI such that energy-efficient water desalination can be achieved.
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Affiliation(s)
- Jinxing Ma
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Junjun Ma
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia; State Key Joint Laboratory of Environment Simulation and Pollution Control, School of Environment, Tsinghua University, Beijing, 100084, China.
| | - Changyong Zhang
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - Jingke Song
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia; State Key Laboratory of Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Tongji University, 1239 Siping Road, Shanghai, 200092, China.
| | - Wenjia Dong
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
| | - T David Waite
- UNSW Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW, 2052, Australia.
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28
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Zhang Y, Wang L, Sun W, Hu Y, Tang H. Membrane technologies for Li+/Mg2+ separation from salt-lake brines and seawater: A comprehensive review. J IND ENG CHEM 2020. [DOI: 10.1016/j.jiec.2019.09.002] [Citation(s) in RCA: 105] [Impact Index Per Article: 26.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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29
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Reale ER, Shrivastava A, Smith KC. Effect of conductive additives on the transport properties of porous flow-through electrodes with insulative particles and their optimization for Faradaic deionization. WATER RESEARCH 2019; 165:114995. [PMID: 31450221 DOI: 10.1016/j.watres.2019.114995] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 08/12/2019] [Accepted: 08/16/2019] [Indexed: 06/10/2023]
Abstract
Deionization devices that use intercalation reactions to reversibly store and release cations from solution show promise for energy-efficient desalination of alternative water resources. Intercalation materials often display low electronic conductivity that results in increased energy consumption during desalination. Accordingly, we performed experiments to quantify the impact of the size and mass fraction of conductive additives and insulative active particles on the effective electronic conductivity, ionic conductivity, and hydraulic permeability of porous electrodes. We find that Ketjen black conductive additives with nodules <50 nm in diameter produce superior electronic conductivity at lower mass fractions than the larger carbon blacks commonly used in capacitive deionization. Hydraulic permeability and effective ionic conductivity depend weakly on carbon black content and size, though smaller active particles decrease hydraulic permeability. Based on these results we analyzed the energy consumption and salt removal rate of different electrode formulations by constructing an electrochemical Ashby plot predicting the variation of desalination performance with electrode transport properties. Optimized electrodes containing insulative Prussian blue analogue (PBA) particles were then fabricated and used in an experimental cation intercalation desalination (CID) cell with symmetric electrodes. For 100 mM NaCl influent energy consumption varied from 7 to 33 kJ/mol when current density increased from 1 to 8 mA/cm2, approaching ten-fold increased salt removal rate at similar energy consumption levels to past CID demonstrations. Complementary numerical and analytical modeling indicates that further improvements in energy consumption and salt removal rate are attainable by enhancing transport in solution and within PBA agglomerates.
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Affiliation(s)
- Erik R Reale
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Aniruddh Shrivastava
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Kyle C Smith
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Department of Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Computational Science and Engineering Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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31
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Liu X, Shanbhag S, Mauter MS. Understanding and mitigating performance decline in electrochemical deionization. Curr Opin Chem Eng 2019. [DOI: 10.1016/j.coche.2019.07.003] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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32
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Wang L, Lin S. Theoretical framework for designing a desalination plant based on membrane capacitive deionization. WATER RESEARCH 2019; 158:359-369. [PMID: 31055016 DOI: 10.1016/j.watres.2019.03.076] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 02/26/2019] [Accepted: 03/05/2019] [Indexed: 06/09/2023]
Abstract
Despite significant progress made in multiple aspects of capacitive deionization (CDI), a rational framework is in need for optimizing the design and operation of a large desalination system based on CDI. In this work, we develop a theoretical framework for guiding the design of a desalination plant based on CDI with ion exchange membranes (i.e. membrane CDI, or MCDI). This framework is established by identifying (1) the practical design constraints, (2) the inter-relationships between different design and operating parameters, (3) a set of independent variables, and (4) the key performance metrics. The proposed design framework reduces the degrees of freedom of the system and facilitates more focused and systematic analysis of the overall performance of an MCDI-based desalination plant. Careful analysis using the proposed design framework suggests the presence of an optimal tradeoff curve that comprises all the possible optima of design and operating conditions with which an MCDI-based desalination plant is the most cost-effective. We also show that the typical practice of using equal flowrates for charging and discharge yields very good performance compared to the optima, as long as water recovery is not too high. Finally, we also briefly explain the implication of this framework on cost-based optimization of the design and operation of an MCDI-based desalination plant.
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Affiliation(s)
- Li Wang
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN, 37235-1831, USA
| | - Shihong Lin
- Department of Civil and Environmental Engineering, Vanderbilt University, Nashville, TN, 37235-1831, USA; Department of Chemical and Bimolecular Engineering, Vanderbilt University, Nashville, TN, 37235-1831, USA.
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Wang L, Lin S. Mechanism of Selective Ion Removal in Membrane Capacitive Deionization for Water Softening. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:5797-5804. [PMID: 31013430 DOI: 10.1021/acs.est.9b00655] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Capacitive deionization (CDI) is an emerging technology capable of selective removal of ions from water. While many studies have reported chemically tailored electrodes for selective ion removal, the selective removal of divalent cations (i.e., hardness) over monovalent cations can simply be achieved using membrane CDI (MCDI) equipped with ion exchange membranes (IEMs). In this study, we use both experimental and modeling approaches to systematically investigate the selective removal of Ca2+ over Na+. Specifically, the impacts of current density, hydraulic retention time, and feed composition on the selectivity of Ca2+ over Na+ were investigated. The results from our study suggest a universal correlation between the ratio of molar fluxes and the ratio of spacer channel ion concentrations, regardless of operating conditions and feed composition. Our analysis also reveals inherent and universal trade-off relationships between selectivity and the Ca2+ removal rate and between selectivity and the degree of Ca2+ removal. This fundamental understanding of the mechanism of selective ion removal in MCDI can also be applied to flow-electrode CDI processes that employ IEMs.
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Affiliation(s)
- Li Wang
- Department of Civil and Environmental Engineering , Vanderbilt University , Nashville , Tennessee 37235-1831 , United States
| | - Shihong Lin
- Department of Civil and Environmental Engineering , Vanderbilt University , Nashville , Tennessee 37235-1831 , United States
- Department of Chemical and Biomolecular Engineering , Vanderbilt University , Nashville , Tennessee 37235-1604 , United States
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Wang L, Dykstra JE, Lin S. Energy Efficiency of Capacitive Deionization. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2019; 53:3366-3378. [PMID: 30802038 DOI: 10.1021/acs.est.8b04858] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Capacitive deionization (CDI) as a class of electrochemical desalination has attracted fast-growing research interest in recent years. A significant part of this growing interest is arguably attributable to the premise that CDI is energy efficient and has the potential to outcompete other conventional desalination technologies. In this review, systematic evaluation of literature data reveals that while the absolute energy consumption of CDI is in general low, most existing CDI systems achieve limited energy efficiency from a thermodynamic perspective. We also analyze the causes for the relatively low energy efficiency and discuss factors that may lead to enhanced energy efficiency for CDI.
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Affiliation(s)
- Li Wang
- Department of Civil and Environmental Engineering , Vanderbilt University , Nashville , Tennessee 37235-1831 , United States
| | - J E Dykstra
- Department of Environmental Technology , Wageningen University , Bornse Weilanden 9 , 6708 WG Wageningen , The Netherlands
| | - Shihong Lin
- Department of Civil and Environmental Engineering , Vanderbilt University , Nashville , Tennessee 37235-1831 , United States
- Department of Chemical and Biomolecular Engineering , Vanderbilt University , Nashville , Tennessee 37235-1604 , United States
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Hawks SA, Ramachandran A, Porada S, Campbell PG, Suss ME, Biesheuvel PM, Santiago JG, Stadermann M. Performance metrics for the objective assessment of capacitive deionization systems. WATER RESEARCH 2019; 152:126-137. [PMID: 30665159 DOI: 10.1016/j.watres.2018.10.074] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 10/25/2018] [Accepted: 10/28/2018] [Indexed: 06/09/2023]
Abstract
In the growing field of capacitive deionization (CDI), a number of performance metrics have emerged to describe the desalination process. Unfortunately, the separation conditions under which these metrics are measured are often not specified, resulting in optimal performance at minimal removal. Here we outline a system of performance metrics and reporting conditions that resolves this issue. Our proposed system is based on volumetric energy consumption (Wh/m3) and throughput productivity (L/h/m2) reported for a specific average concentration reduction, water recovery, and feed salinity. To facilitate and rationalize comparisons between devices, materials, and operation modes, we propose a nominal standard separation of removing 5 mM from a 20 mM NaCl feed solution at 50% water recovery. We propose this particular separation as a standard, but emphasize that the rationale presented here applies irrespective of separation details. Using our proposed separation, we compare the desalination performance of a flow-through electrode (fte-CDI) cell and a flow between membrane (fb-MCDI) device, showing how significantly different systems can be compared in terms of generally desirable desalination characteristics. In general, we find that performance analysis must be considered carefully so to not allow for ambiguous separation conditions or the maximization of one metric at the expense of another. Additionally, for context and clarity, we discuss a number of important underlying performance indicators and cell characteristics that are not performance measures in and of themselves but can be examined to better understand differences in performance.
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Affiliation(s)
- Steven A Hawks
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA, United States
| | - Ashwin Ramachandran
- Department of Aeronautics & Astronautics, Stanford University, Stanford, CA, 94305, United States
| | - Slawomir Porada
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, The Netherlands; Soft Matter, Fluidics and Interfaces Group, Faculty of Science and Technology, University of Twente, Meander ME 314, 7500 AE, Enschede, the Netherlands
| | - Patrick G Campbell
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA, United States
| | - Matthew E Suss
- Faculty of Mechanical Engineering, Technion-Israel Institute of Technology, Haifa, Israel
| | - P M Biesheuvel
- Wetsus, European Centre of Excellence for Sustainable Water Technology, Oostergoweg 9, 8911 MA, Leeuwarden, The Netherlands
| | - Juan G Santiago
- Department of Mechanical Engineering, Stanford University, Stanford, CA, 94305, United States
| | - Michael Stadermann
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA, United States.
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36
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Shi W, Liu X, Ye C, Cao X, Gao C, Shen J. Efficient lithium extraction by membrane capacitive deionization incorporated with monovalent selective cation exchange membrane. Sep Purif Technol 2019. [DOI: 10.1016/j.seppur.2018.09.006] [Citation(s) in RCA: 77] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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37
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Liu X, Whitacre JF, Mauter MS. Mechanisms of Humic Acid Fouling on Capacitive and Insertion Electrodes for Electrochemical Desalination. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:12633-12641. [PMID: 30240196 DOI: 10.1021/acs.est.8b03261] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Though electrochemical deionization technologies have been widely explored for brackish water desalination and selective ion removal, their sustained performance in the presence of foulants common to environmental waters remains unclear. This study investigates the fundamental mechanisms by which carbonaceous electrodes used in capacitive deionization and insertion electrodes used for high-capacity selective ion removal are affected by the presence of humic acid (HA). We evaluate HA adsorption behavior and the resulting impact on the ion storage capacity and cycling stability of the electrode materials. We find that HA is primarily adsorbed to the mesopores of two carbonaceous electrodes with distinctly different pore structures, but that the ion storage and transport properties of the electrodes are not significantly impacted by HA adsorption. In contrast, HA adsorption resulted in sharp capacity decay for the insertion (Na4Mn9O18) electrode. We attribute this decay to both hindered Na+ ion diffusion to the insertion interface in the presence of adsorbed HA, as well as HA mediated electrode dissolution. These findings highlight the contrasting mechanisms for HA fouling of capacitive and insertion electrodes and suggest that insertion electrodes may be more susceptible to performance decline in electrochemical deionization of environmental waters.
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Affiliation(s)
- Xitong Liu
- Department of Civil & Environmental Engineering , Carnegie Mellon University , 5000 Forbes Avenue , Pittsburgh , Pennsylvania 15213 , United States
| | - Jay F Whitacre
- Department of Engineering and Public Policy , Carnegie Mellon University , 5000 Forbes Avenue , Pittsburgh , Pennsylvania 15213 , United States
- Department of Material Science and Engineering , Carnegie Mellon University , 5000 Forbes Avenue , Pittsburgh , Pennsylvania 15213 , United States
- The Scott Institute for Energy Innovation , Carnegie Mellon University , 5000 Forbes Avenue , Pittsburgh , Pennsylvania 15213 , United States
| | - Meagan S Mauter
- Department of Civil & Environmental Engineering , Carnegie Mellon University , 5000 Forbes Avenue , Pittsburgh , Pennsylvania 15213 , United States
- Department of Engineering and Public Policy , Carnegie Mellon University , 5000 Forbes Avenue , Pittsburgh , Pennsylvania 15213 , United States
- The Scott Institute for Energy Innovation , Carnegie Mellon University , 5000 Forbes Avenue , Pittsburgh , Pennsylvania 15213 , United States
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Ramachandran A, Hawks SA, Stadermann M, Santiago JG. Frequency analysis and resonant operation for efficient capacitive deionization. WATER RESEARCH 2018; 144:581-591. [PMID: 30092504 DOI: 10.1016/j.watres.2018.07.066] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 07/25/2018] [Accepted: 07/26/2018] [Indexed: 06/08/2023]
Abstract
Capacitive deionization (CDI) performance metrics can vary widely with operating methods. Conventional CDI operating methods such as constant current and constant voltage show advantages in either energy or salt removal performance, but not both. We here develop a theory around and experimentally demonstrate a new operation for CDI that uses sinusoidal forcing voltage (or sinusoidal current). We use a dynamic system modeling approach, and quantify the frequency response (amplitude and phase) of CDI effluent concentration. Using a wide range of operating conditions, we demonstrate that CDI can be modeled as a linear time invariant system. We validate this model with experiments, and show that a sinusoid voltage operation can simultaneously achieve high salt removal and strong energy performance, thus very likely making it superior to other conventional operating methods. Based on the underlying coupled phenomena of electrical charge (and ionic) transfer with bulk advection in CDI, we derive and validate experimentally the concept of using sinusoidal voltage forcing functions to achieve resonance-type operation for CDI. Despite the complexities of the system, we find a simple relation for the resonant time scale: the resonant time period (frequency) is proportional (inversely proportional) to the geometric mean of the flow residence time and the electrical (RC) charging time. Operation at resonance implies the optimal balance between absolute amount of salt removed (in moles) and dilution (depending on the feed volume processed), thus resulting in the maximum average concentration reduction for the desalinated water. We further develop our model to generalize the resonant time-scale operation, and provide responses for square and triangular voltage waveforms as two examples. To this end, we develop a general tool that uses Fourier analysis to construct CDI effluent dynamics for arbitrary input waveforms. Using this tool, we show that most of the salt removal (∼95%) for square and triangular voltage forcing waveforms is achieved by the fundamental Fourier (sinusoidal) mode. The frequency of higher Fourier modes precludes high flow efficiency for these modes, so these modes consume additional energy for minimal additional salt removed. This deficiency of higher frequency modes further highlights the advantage of DC-offset sinusoidal forcing for CDI operation.
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Affiliation(s)
- Ashwin Ramachandran
- Department of Aeronautics & Astronautics, Stanford University, Stanford, CA, 94305, United States
| | - Steven A Hawks
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA, 94550, United States
| | - Michael Stadermann
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA, 94550, United States
| | - Juan G Santiago
- Department of Mechanical Engineering, Stanford University, Stanford, CA, 94305, United States.
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Hemmatifar A, Ramachandran A, Liu K, Oyarzun DI, Bazant MZ, Santiago JG. Thermodynamics of Ion Separation by Electrosorption. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2018; 52:10196-10204. [PMID: 30141621 DOI: 10.1021/acs.est.8b02959] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We present a simple, top-down approach for the calculation of minimum energy consumption of electrosorptive ion separation using variational form of the (Gibbs) free energy. We focus and expand on the case of electrostatic capacitive deionization (CDI). The theoretical framework is independent of details of the double-layer charge distribution and is applicable to any thermodynamically consistent model, such as the Gouy-Chapman-Stern and modified Donnan models. We demonstrate that, under certain assumptions, the minimum required electric work energy is indeed equivalent to the free energy of separation. Using the theory, we define the thermodynamic efficiency of CDI. We show that the thermodynamic efficiency of current experimental CDI systems is currently very low, around 1% for most existing systems. We applied this knowledge and constructed and operated a CDI cell to show that judicious selection of the materials, geometry, and process parameters can lead to a 9% thermodynamic efficiency and 4.6 kT per removed ion energy cost. This relatively high thermodynamic efficiency is, to our knowledge, by far the highest thermodynamic efficiency ever demonstrated for traditional CDI. We hypothesize that efficiency can be further improved by further reduction of CDI cell series resistances and optimization of operational parameters.
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Affiliation(s)
- Ali Hemmatifar
- Department of Mechanical Engineering , Stanford University , Stanford , California 94305 , United States
| | - Ashwin Ramachandran
- Department of Aeronautics & Astronautics , Stanford University , Stanford , California 94305 , United States
| | - Kang Liu
- Department of Mechanical Engineering , Stanford University , Stanford , California 94305 , United States
| | - Diego I Oyarzun
- Department of Mechanical Engineering , Stanford University , Stanford , California 94305 , United States
| | - Martin Z Bazant
- Departments of Chemical Engineering and Mathematics , Massachusetts Institute of Technology , Cambridge , Massachusetts 02139 , United States
| | - Juan G Santiago
- Department of Mechanical Engineering , Stanford University , Stanford , California 94305 , United States
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Ramachandran A, Hemmatifar A, Hawks SA, Stadermann M, Santiago JG. Self similarities in desalination dynamics and performance using capacitive deionization. WATER RESEARCH 2018; 140:323-334. [PMID: 29734040 DOI: 10.1016/j.watres.2018.04.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Revised: 04/16/2018] [Accepted: 04/17/2018] [Indexed: 06/08/2023]
Abstract
Charge transfer and mass transport are two underlying mechanisms which are coupled in desalination dynamics using capacitive deionization (CDI). We developed simple reduced-order models based on a mixed reactor volume principle which capture the coupled dynamics of CDI operation using closed-form semi-analytical and analytical solutions. We use the models to identify and explore self-similarities in the dynamics among flow rate, current, and voltage for CDI cell operation including both charging and discharging cycles. The similarity approach identifies the specific combination of cell (e.g. capacitance, resistance) and operational parameters (e.g. flow rate, current) which determine a unique effluent dynamic response. We here demonstrate self-similarity using a conventional flow between CDI (fbCDI) architecture, and we hypothesize that our similarity approach has potential application to a wide range of designs. We performed an experimental study of these dynamics and used well-controlled experiments of CDI cell operation to validate and explore limits of the model. For experiments, we used a CDI cell with five electrode pairs and a standard flow between (electrodes) architecture. Guided by the model, we performed a series of experiments that demonstrate natural response of the CDI system. We also identify cell parameters and operation conditions which lead to self-similar dynamics under a constant current forcing function and perform a series of experiments by varying flowrate, currents, and voltage thresholds to demonstrate self-similarity. Based on this study, we hypothesize that the average differential electric double layer (EDL) efficiency (a measure of ion adsorption rate to EDL charging rate) is mainly dependent on user-defined voltage thresholds, whereas flow efficiency (measure of how well desalinated water is recovered from inside the cell) depends on cell volumes flowed during charging, which is determined by flowrate, current and voltage thresholds. Results of experiments strongly support this hypothesis. Results show that cycle efficiency and salt removal for a given flowrate and current are maximum when average EDL and flow efficiencies are approximately equal. We further explored a range of CC operations with varying flowrates, currents, and voltage thresholds using our similarity variables to highlight trade-offs among salt removal, energy, and throughput performance.
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Affiliation(s)
- Ashwin Ramachandran
- Department of Aeronautics & Astronautics, Stanford University, Stanford, CA, 94305, United States
| | - Ali Hemmatifar
- Department of Mechanical Engineering, Stanford University, Stanford, CA, 94305, United States
| | - Steven A Hawks
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA, 94550, United States
| | - Michael Stadermann
- Lawrence Livermore National Laboratory, 7000 East Avenue, Livermore, CA, 94550, United States
| | - Juan G Santiago
- Department of Mechanical Engineering, Stanford University, Stanford, CA, 94305, United States.
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Liu S, Smith KC. Quantifying the trade-offs between energy consumption and salt removal rate in membrane-free cation intercalation desalination. Electrochim Acta 2018. [DOI: 10.1016/j.electacta.2018.03.065] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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