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Tu WH, Zhao Y, Chan WP, Lisak G. Reclaimed seawater discharge - Desalination brine treatment and resource recovery system. WATER RESEARCH 2024; 251:121096. [PMID: 38184912 DOI: 10.1016/j.watres.2023.121096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 12/12/2023] [Accepted: 12/30/2023] [Indexed: 01/09/2024]
Abstract
With the proliferation of reverse osmosis technology, seawater reverse osmosis desalination has been heralded as the solution to water scarcity for coastal regions. However, the large volume of desalination brine produced may pose an adverse environmental impact when directly discharged into the sea and result in energy wastage as the seawater pumped out is dumped back into the sea. Recently, zero liquid discharge has been extensively studied as a way to eliminate the aquatic ecotoxicity impact completely, despite being expensive and having a high carbon footprint. In this work, we propose a new strategy towards the treatment of brine to seawater level for disposal, dubbed reclaimed seawater discharge (RSD). This process is coupled with existing resource recovery techniques and waste alkali CO2 capture processes to produce an economically viable waste treatment process with minimal CO2 emissions. In this work, we placed significant focus on the electrolysis of brine, which simultaneously lowers the salinity of the desalination brine (56.0 ± 2.1 g/L) to seawater level (32.0 ± 1.4 g/L), generates alkali brine from seawater (pH 13.6) to remove impurities in brine (Mg2+ and Ca2+ to below ppm level), and recovers magnesium hydroxide, calcium carbonate, chlorine, bromine, and hydrogen gas as valuable resources. The RSD is further chemically dechlorinated and neutralised to pH 7.3 to be safe to discharge into the sea. The excess alkali brine is used to capture additional CO2 in the form of bicarbonates, achieving net abatement in climate change impact (9.90 CO2 e/m3) after product carbon abatements are accounted.
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Affiliation(s)
- Wei Han Tu
- Resource and Reclamation Centre (R3C), Nanyang Environment and Water Research Institute (NEWRI), 1 Clean Tech Loop, 637141, Singapore
| | - Ya Zhao
- Resource and Reclamation Centre (R3C), Nanyang Environment and Water Research Institute (NEWRI), 1 Clean Tech Loop, 637141, Singapore
| | - Wei Ping Chan
- Resource and Reclamation Centre (R3C), Nanyang Environment and Water Research Institute (NEWRI), 1 Clean Tech Loop, 637141, Singapore
| | - Grzegorz Lisak
- Resource and Reclamation Centre (R3C), Nanyang Environment and Water Research Institute (NEWRI), 1 Clean Tech Loop, 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798, Singapore.
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Bao Y, Hao J, Zhang S, Zhu D, Li F. Structural/Compositional-Tailoring of Nickel Hexacyanoferrate Electrodes for Highly Efficient Capacitive Deionization. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2023; 19:e2300384. [PMID: 37116117 DOI: 10.1002/smll.202300384] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2023] [Revised: 04/18/2023] [Indexed: 06/19/2023]
Abstract
Prussian blue analogs (PBAs) represent a crucial class of intercalation electrode materials for electrochemical water desalination. It is shown here that structural/compositional tailoring of PBAs, the nickel hexacyanoferrate (NiHCF) electrodes in particular, can efficiently modulate their capacitive deionization (CDI) performance (e.g., desalination capacity, cyclability, selectivity, etc.). Both the desalination capacity and the cyclability of NiHCF electrodes are highly dependent on their structural/compositional features such as crystallinity, morphology, hierarchy, and coatings. It is demonstrated that the CDI cell with hierarchically structured NiHCF nanoframe (NiHCF-NF) electrode exhibits a superior desalination capacity of 121.38 mg g-1 , a high charge efficiency of up to 82%, and a large capacity retention of 88% after 40 cycles intercalation/deintercalation. In addition, it is discovered that coating of carbon (C) film over NiHCF can lower its desalination capacity owing to the partial blockage of diffusion openings by the coated C film. Moreover, the hierarchical NiHCF-NF electrode also demonstrates a superior selectivity toward monovalent sodium ions (Na+ ) over divalent calcium (Ca2+ ) and magnesim (Mg2+ ) ions, allowing it to be a promising platform for preferential capturing Na+ ions from brines. Overall, the structural/compositional tailoring strategies would offer a viable option for the rational design of other intercalation electrode materials applied in CDI techniques.
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Affiliation(s)
- Yang Bao
- Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, 219 Ningliu Road, Nanjing, 210044, China
| | - Jinxin Hao
- Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, 219 Ningliu Road, Nanjing, 210044, China
| | - Shu Zhang
- Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, 219 Ningliu Road, Nanjing, 210044, China
| | - Dechun Zhu
- NUIST Reading Academy, Nanjing University of Information Science and Technology, 219 Ningliu Road, Nanjing, 210044, China
| | - Feihu Li
- Collaborative Innovation Center of Atmospheric Environment and Equipment Technology, Jiangsu Key Laboratory of Atmospheric Environment Monitoring and Pollution Control, School of Environmental Science and Engineering, Nanjing University of Information Science and Technology, 219 Ningliu Road, Nanjing, 210044, China
- NUIST Reading Academy, Nanjing University of Information Science and Technology, 219 Ningliu Road, Nanjing, 210044, China
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