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Simões C, Saakes M, Brilman D. Toward Redox-Free Reverse Electrodialysis with Carbon-Based Slurry Electrodes. Ind Eng Chem Res 2023; 62:1665-1675. [PMID: 36719299 PMCID: PMC9881007 DOI: 10.1021/acs.iecr.2c03567] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 01/04/2023] [Accepted: 01/05/2023] [Indexed: 01/15/2023]
Abstract
Clean and renewable salinity gradient energy can be harvested using reverse electrodialysis (RED). The electrode system is an essential part to convert ionic current into electrical current. In this study, a typical 0.10 × 0.10 m2 RED stack with a cross-flow configuration was used to test carbon-based slurry electrodes (CSEs) to replace the usual redox solutions, like hexacyanoferrate, to enhance the RED process' sustainability, stability, and economic value. Six different slurry compositions comprising activated carbon, carbon black, and graphite powder were tested. The CSE characteristics were systematically studied by measuring viscosity, electrode compartment pressure drop, maximum current density, stability, and performance of power density and energy efficiency. Using a single membrane configuration, the CSE ran continuously for 17 days with a stable output. The application of CSEs for RED, with artificial seawater and river water, using mixing activated carbon and carbon black at a total concentration of 20 wt %, resulted in the best performance with a net power density of 0.7 W·m-2. Moreover, higher current densities up to 350 A·m-2 were tested for ED and shown to be feasible until 150 A·m-2. CSEs show promising versatility for different application modes.
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Affiliation(s)
- Catarina Simões
- Wetsus,
European Centre of Excellence for Sustainable Water Technology, PO Box 1113, Leeuwarden 8900 CC, The
Netherlands
- Sustainable
Process Technology, Faculty of Science and Technology, University of Twente, PO Box 217, Enschede 7500 AE, The Netherlands
| | - Michel Saakes
- Wetsus,
European Centre of Excellence for Sustainable Water Technology, PO Box 1113, Leeuwarden 8900 CC, The
Netherlands
| | - Derk Brilman
- Sustainable
Process Technology, Faculty of Science and Technology, University of Twente, PO Box 217, Enschede 7500 AE, The Netherlands
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Sun H, Zhang X, Zheng Z, Cui M, Liu H, Wu P, Liu H. Effective mitigation of ammonia in sewage-sludge-derived fermentation liquid using flow-electrode capacitive deionization. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2023; 325:116630. [PMID: 36419295 DOI: 10.1016/j.jenvman.2022.116630] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 10/10/2022] [Accepted: 10/24/2022] [Indexed: 06/16/2023]
Abstract
Due to the high toxicity of ammonia to organisms and its contribution to eutrophication in surface water, the risk of emission of ammonia and other nitrogenous ions to the environment and ecosystems has aroused wide concerns. Therefore, the discharge criterion on nitrogen in effluent from conventional wastewater treatment plants (WWTP) is very stringent. Furthermore, during the conventional denitrification processes, the relatively costly external carbon source is usually required. Nowadays production of volatile fatty acids (VFAs) from sewage sludge by alkaline anaerobic fermentation has regarded as an attractive carbon source. However, usually ammonia is quite abundant in the fermentation liquid and thus effective mitigation of ammonia in the fermentation liquid is also a significant step for its further utilization. In the present study, the flow electrode capacitive deionization (FCDI) was applied to remove ammonia in the fermentation liquid of sewage sludge. Firstly, response surface method (RSM) was employed to optimize parameters and then the performance of the FCDI in ammonia removal were examined. Results showed that optimal flow rates, carbon content and ammonia concentration were 8.0 mL min-1, 4.0 wt% and 110 mg N·L-1 and the ammonia removal efficiency (ARE) reached 42.7%, while treating the alkaline fermentation liquid. Seemingly the presence of Na+ and polypeptides in the liquid with their average RE of 53.3% and 11.1% substantially compromised ammonia removal probably due to the competition of adsorption sites. This present study serves as a proven concept for the feasibility of the application of the FCDI system in ammonia separation from the VFAs, which could realize economic and ecological benefits.
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Affiliation(s)
- Huimin Sun
- School of Environment and Civil Engineering, Jiangnan University, Wuxi, 214122, China
| | - Xuedong Zhang
- School of Environment and Civil Engineering, Jiangnan University, Wuxi, 214122, China; Jiangsu Key Laboratory of Anaerobic Biotechnology, Wuxi, 214122, China.
| | - Zhiyong Zheng
- School of Environment and Civil Engineering, Jiangnan University, Wuxi, 214122, China; Jiangsu Key Laboratory of Anaerobic Biotechnology, Wuxi, 214122, China; Jiangsu Collaborative Innovation Center of Water Treatment Technology and Material, Suzhou, 215011, China
| | - Minhua Cui
- School of Environment and Civil Engineering, Jiangnan University, Wuxi, 214122, China; Jiangsu Key Laboratory of Anaerobic Biotechnology, Wuxi, 214122, China; Jiangsu Collaborative Innovation Center of Water Treatment Technology and Material, Suzhou, 215011, China
| | - Hongbo Liu
- School of Environment and Civil Engineering, Jiangnan University, Wuxi, 214122, China; Jiangsu Key Laboratory of Anaerobic Biotechnology, Wuxi, 214122, China; Jiangsu Collaborative Innovation Center of Water Treatment Technology and Material, Suzhou, 215011, China
| | - Ping Wu
- School of Environment and Civil Engineering, Jiangnan University, Wuxi, 214122, China
| | - He Liu
- School of Environment and Civil Engineering, Jiangnan University, Wuxi, 214122, China; Jiangsu Key Laboratory of Anaerobic Biotechnology, Wuxi, 214122, China; Jiangsu Collaborative Innovation Center of Water Treatment Technology and Material, Suzhou, 215011, China.
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