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Elewa MM, El Batouti M, Al-Harby NF. A Comparison of Capacitive Deionization and Membrane Capacitive Deionization Using Novel Fabricated Ion Exchange Membranes. Materials (Basel) 2023; 16:4872. [PMID: 37445186 DOI: 10.3390/ma16134872] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 07/05/2023] [Accepted: 07/05/2023] [Indexed: 07/15/2023]
Abstract
Another technique for desalination, known as membrane capacitive deionization (MCDI), has been investigated as an alternative. This approach has the potential to lower the voltage that is required, in addition to improving the ability to renew the electrodes. In this study, the desalination effectiveness of capacitive deionization (CDI) was compared to that of MCDI, employing newly produced cellulose acetate ion exchange membranes (IEMs), which were utilized for the very first time in MCDI. As expected, the salt adsorption and charge efficiency of MCDI were shown to be higher than those of CDI. Despite this, the unique electrosorption behavior of the former reveals that ion transport via the IEMs is a crucial rate-controlling step in the desalination process. We monitored the concentration of salt in the CDI and MCDI effluent streams, but we also evaluated the pH of the effluent stream in each of these systems and investigated the factors that may have caused these shifts. The significant change in pH that takes place during one adsorption and desorption cycle in CDI (pH range: 2.3-11.6) may cause problems in feed water that already contains components that are prone to scaling. In the case of MCDI, the fall in pH was only slightly more noticeable. Based on these findings, it appears that CDI and MCDI are promising new desalination techniques that has the potential to be more ecologically friendly and efficient than conventional methods of desalination. MCDI has some advantages over CDI in its higher salt removal efficiency, faster regeneration, and longer lifetime, but it is also more expensive and complex. The best choice for a particular application will depend on the specific requirements.
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Affiliation(s)
- Mahmoud M Elewa
- Arab Academy for Science, Technology and Maritime Transport, Alexandria P.O. Box 1029, Egypt
| | - Mervette El Batouti
- Chemistry Department, Faculty of Science, Alexandria University, Alexandria 21526, Egypt
| | - Nouf F Al-Harby
- Department of Chemistry, College of Science, Qassim University, Buraydah 51452, Saudi Arabia
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2
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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. Int J Environ Res 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] [What about the content of this article? (0)] [Affiliation(s)] [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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Zuo K, Huang X, Liu X, Gil Garcia EM, Kim J, Jain A, Chen L, Liang P, Zepeda A, Verduzco R, Lou J, Li Q. A Hybrid Metal-Organic Framework-Reduced Graphene Oxide Nanomaterial for Selective Removal of Chromate from Water in an Electrochemical Process. Environ Sci Technol 2020; 54:13322-13332. [PMID: 32966059 DOI: 10.1021/acs.est.0c04703] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Hexavalent chromium Cr(VI) is a highly toxic groundwater contaminant. In this study, we demonstrate a selective electrochemical process tailored for removal of Cr(VI) using a hybrid MOF@rGO nanomaterial synthesized by in situ growth of a nanocrystalline, mixed ligand octahedral metal-organic framework with cobalt metal centers, [Co2(btec)(bipy)(DMF)2]n (Co-MOF), on the surface of reduced graphene oxide (rGO). The rGO provides the electric conductivity necessary for an electrode, while the Co-MOF endows highly selective adsorption sites for CrO42-. When used as an anode in the treatment cycles, the MOF@rGO electrode exhibits strong selectivity for adsorption of CrO42- over competing anions including Cl-, SO42-, and As(III) and achieves charge efficiency (CE) >100% due to the strong physisorption of CrO42- by Co-MOF; both electro- and physisorption capacities are regenerated with the reversal of the applied voltage, when highly toxic Cr(VI) is reduced to less toxic reduced Cr species and subsequently released into brine. This approach allows easy regeneration of the nonconducting Co-MOF without any chemical addition while simultaneously transforming Cr(VI), inspiring a novel electrochemical method for highly selective degradation of toxic contaminants using tailor-designed electrodes with high affinity adsorbents.
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Affiliation(s)
- Kuichang Zuo
- Department of Civil and Environmental Engineering, Rice University, MS 319, 6100 Main Street, Houston 77005, United States
- NSF Nanosystems Engineering Research Center Nanotechnology-Enabled Water Treatment, Rice University, MS 6398, 6100 Main Street, Houston 77005, United States
| | - Xiaochuan Huang
- Department of Civil and Environmental Engineering, Rice University, MS 319, 6100 Main Street, Houston 77005, United States
- NSF Nanosystems Engineering Research Center Nanotechnology-Enabled Water Treatment, Rice University, MS 6398, 6100 Main Street, Houston 77005, United States
| | - Xingchen Liu
- Department of Civil and Environmental Engineering, Rice University, MS 319, 6100 Main Street, Houston 77005, United States
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Eva Maria Gil Garcia
- Department of Civil and Environmental Engineering, Rice University, MS 319, 6100 Main Street, Houston 77005, United States
- Facultad de Ingeniería Química, Universidad Autónoma de Yucatán, Campus de Ingenierías y Ciencias Exactas, Periférico Norte km 33.5, 97203 Mérida, Yucatan, Mexico
| | - Jun Kim
- Department of Civil and Environmental Engineering, Rice University, MS 319, 6100 Main Street, Houston 77005, United States
- NSF Nanosystems Engineering Research Center Nanotechnology-Enabled Water Treatment, Rice University, MS 6398, 6100 Main Street, Houston 77005, United States
- Access Business Group, 7575 Fulton Street East, Ada, Michigan 49355, United States
| | - Amit Jain
- NSF Nanosystems Engineering Research Center Nanotechnology-Enabled Water Treatment, Rice University, MS 6398, 6100 Main Street, Houston 77005, United States
- Department of Chemical and Biomolecular Engineering, Rice University, MS 362, 6100 Main Street, Houston 77005, United States
| | - Long Chen
- NSF Nanosystems Engineering Research Center Nanotechnology-Enabled Water Treatment, Rice University, MS 6398, 6100 Main Street, Houston 77005, United States
- Department of Materials Science and Nano Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Peng Liang
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Alejandro Zepeda
- Facultad de Ingeniería Química, Universidad Autónoma de Yucatán, Campus de Ingenierías y Ciencias Exactas, Periférico Norte km 33.5, 97203 Mérida, Yucatan, Mexico
| | - Rafael Verduzco
- NSF Nanosystems Engineering Research Center Nanotechnology-Enabled Water Treatment, Rice University, MS 6398, 6100 Main Street, Houston 77005, United States
- Department of Chemical and Biomolecular Engineering, Rice University, MS 362, 6100 Main Street, Houston 77005, United States
| | - Jun Lou
- NSF Nanosystems Engineering Research Center Nanotechnology-Enabled Water Treatment, Rice University, MS 6398, 6100 Main Street, Houston 77005, United States
- Department of Materials Science and Nano Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
| | - Qilin Li
- Department of Civil and Environmental Engineering, Rice University, MS 319, 6100 Main Street, Houston 77005, United States
- NSF Nanosystems Engineering Research Center Nanotechnology-Enabled Water Treatment, Rice University, MS 6398, 6100 Main Street, Houston 77005, United States
- Department of Materials Science and Nano Engineering, Rice University, 6100 Main Street, Houston, Texas 77005, United States
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Abstract
Capacitive deionization (CDI) features a low-cost and energy-efficient desalination approach based on electrosorption of saline ions. To enhance the salt electrosorption capacity of CDI electrodes, we coat ion-selective pseudocapacitive layers (MnO2 and Ag) onto porous carbon electrodes (activated carbon cloth) with only minimal use of a conductive additive and a polymer binder (<1 wt % in total). Optimized pseudocapacitive electrodes result in excellent single-electrode specific capacitance (>300 F/g) and great cell stability (70% retention after 500 cycles). A CDI cell out of these pseudocapacitive electrodes yields as high charge efficiency as 83% and a remarkable salt adsorption capacity up to 17.8 mg/g. Our finding of outstanding CDI performance of the pseudocapacitive electrodes with no use of costly ion-exchange membranes highlights the significant role of a pseudocapacitive layer in the electrosorption process.
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Affiliation(s)
- Meng Li
- Nanoscience for Energy Technology and Sustainability, Department of Mechanical and Process Engineering, Eidgenössische Technische Hochschule (ETH) Zürich , Tannenstrasse 3, Zürich CH-8092, Switzerland
| | - Hyung Gyu Park
- Nanoscience for Energy Technology and Sustainability, Department of Mechanical and Process Engineering, Eidgenössische Technische Hochschule (ETH) Zürich , Tannenstrasse 3, Zürich CH-8092, Switzerland
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Porada S, Schipper F, Aslan M, Antonietti M, Presser V, Fellinger TP. Capacitive Deionization using Biomass-based Microporous Salt-Templated Heteroatom-Doped Carbons. ChemSusChem 2015; 8:1867-1874. [PMID: 25970654 DOI: 10.1002/cssc.201500166] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/31/2015] [Indexed: 06/04/2023]
Abstract
Microporous carbons are an interesting material for electrochemical applications. In this study, we evaluate several such carbons without/with N or S doping with regard to capacitive deionization. For this purpose, we extent the salt-templating synthesis towards biomass precursors and S-doped microporous carbons. The sample with the largest specific surface area (2830 m(2) g(-1) ) showed 1.0 wt % N and exhibited a high salt-sorption capacity of 15.0 mg g(-1) at 1.2 V in 5 mM aqueous NaCl. While being a promising material from an equilibrium performance point of view, our study also gives first insights to practical limitations of heteroatom-doped carbon materials. We show that high heteroatom content may be associated with a low charge efficiency. The latter is a key parameter for capacitive deionization and is defined as the ratio between the amounts of removed salt molecules and electrical charge.
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Affiliation(s)
- Slawomir Porada
- INM - Leibniz Institute for New Materials, Campus D2 2, 66123 Saarbrücken (Germany)
| | - Florian Schipper
- Max Planck Institute of Colloids and Interfaces, Colloids Department, Am Mühlenberg 1, 14476 Potsdam (Germany)
| | - Mesut Aslan
- INM - Leibniz Institute for New Materials, Campus D2 2, 66123 Saarbrücken (Germany)
| | - Markus Antonietti
- Max Planck Institute of Colloids and Interfaces, Colloids Department, Am Mühlenberg 1, 14476 Potsdam (Germany)
| | - Volker Presser
- INM - Leibniz Institute for New Materials, Campus D2 2, 66123 Saarbrücken (Germany).
- Department of Materials Science and Engineering, Saarland University, Campus D2 2, 66123 Saarbrücken (Germany).
| | - Tim-Patrick Fellinger
- Max Planck Institute of Colloids and Interfaces, Colloids Department, Am Mühlenberg 1, 14476 Potsdam (Germany).
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