Simultaneous electrochemical leaching, enrichment, and recovery of phosphorus as value-added vivianite from poly-aluminum chloride (PAC) sludge
Electrochemical recovery of phosphorus (P) from waste sludge presents a sustainable solution to mitigate the depletion of P rock reserves. However, its feasibility and cost have been persistent challenges. This study introduces an innovative strategy for simultaneous electrochemical leaching, enrich...
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Elsevier
2025-12-01
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| Series: | Water Research X |
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| author | Hongjie Guo Xiaolong Lu Hameer Chand Changyong Zhang |
| author_facet | Hongjie Guo Xiaolong Lu Hameer Chand Changyong Zhang |
| author_sort | Hongjie Guo |
| collection | DOAJ |
| description | Electrochemical recovery of phosphorus (P) from waste sludge presents a sustainable solution to mitigate the depletion of P rock reserves. However, its feasibility and cost have been persistent challenges. This study introduces an innovative strategy for simultaneous electrochemical leaching, enrichment, and recovery of P (ELER) from poly-aluminum chloride (PAC) sludge with minimal chemical and energy input. A high P leaching efficiency of 90.5% was achieved within the cathode chamber through the rapid elevation of pH induced by water electrolysis at an optimal current density of 30 A m−2 during a single 5-hour cycle. The ELER system recovered approximately 68.8% P from the simulated PAC sludge at a specific energy consumption (SEC) of 214.4 kWh kg−1 P. Notably, the selection and composition of the electrolytes played a crucial role in system performances, with Na2SO4 outperforming NaCl in both efficiency and stability. Increasing catholyte concentration or reducing anolyte concentration significantly reduced P leaching and enrichment efficiency. Furthermore, when optimized for continuous operation over five successive cycles, the system can achieve an ultimate P enrichment efficiency of 96.5% for real PAC sludge, while maintaining a relative low SEC of 54.1 kWh kg−1 P. The enriched P was crystallized as high-purity vivianite, a value-added product that can be utilized as a slow-release P fertilizer or a precursor for lithium-ion battery electrodes. The estimated cost of $4.3 kg−1 P makes this approach economically viable compared to other existing technologies. This innovative approach holds promise for efficient and sustainable P recovery from PAC sludge or other P-rich waste solid. |
| format | Article |
| id | doaj-art-e59f35843dcc4bb4982639707d0c609b |
| institution | OA Journals |
| issn | 2589-9147 |
| language | English |
| publishDate | 2025-12-01 |
| publisher | Elsevier |
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| series | Water Research X |
| spelling | doaj-art-e59f35843dcc4bb4982639707d0c609b2025-08-20T01:52:55ZengElsevierWater Research X2589-91472025-12-012910033710.1016/j.wroa.2025.100337Simultaneous electrochemical leaching, enrichment, and recovery of phosphorus as value-added vivianite from poly-aluminum chloride (PAC) sludgeHongjie Guo0Xiaolong Lu1Hameer Chand2Changyong Zhang3CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026, China; College of Mining Engineering, Taiyuan University of Technology, Taiyuan, Shanxi 030024, ChinaCAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026, ChinaCAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026, ChinaCAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026, China; Corresponding author at: CAS Key Laboratory of Urban Pollutant Conversion, Department of Environmental Science and Engineering, University of Science and Technology of China, Hefei, 230026 China.Electrochemical recovery of phosphorus (P) from waste sludge presents a sustainable solution to mitigate the depletion of P rock reserves. However, its feasibility and cost have been persistent challenges. This study introduces an innovative strategy for simultaneous electrochemical leaching, enrichment, and recovery of P (ELER) from poly-aluminum chloride (PAC) sludge with minimal chemical and energy input. A high P leaching efficiency of 90.5% was achieved within the cathode chamber through the rapid elevation of pH induced by water electrolysis at an optimal current density of 30 A m−2 during a single 5-hour cycle. The ELER system recovered approximately 68.8% P from the simulated PAC sludge at a specific energy consumption (SEC) of 214.4 kWh kg−1 P. Notably, the selection and composition of the electrolytes played a crucial role in system performances, with Na2SO4 outperforming NaCl in both efficiency and stability. Increasing catholyte concentration or reducing anolyte concentration significantly reduced P leaching and enrichment efficiency. Furthermore, when optimized for continuous operation over five successive cycles, the system can achieve an ultimate P enrichment efficiency of 96.5% for real PAC sludge, while maintaining a relative low SEC of 54.1 kWh kg−1 P. The enriched P was crystallized as high-purity vivianite, a value-added product that can be utilized as a slow-release P fertilizer or a precursor for lithium-ion battery electrodes. The estimated cost of $4.3 kg−1 P makes this approach economically viable compared to other existing technologies. This innovative approach holds promise for efficient and sustainable P recovery from PAC sludge or other P-rich waste solid.http://www.sciencedirect.com/science/article/pii/S2589914725000362Phosphorous recoveryPAC sludgeElectrochemical leachingVivianiteSustainability |
| spellingShingle | Hongjie Guo Xiaolong Lu Hameer Chand Changyong Zhang Simultaneous electrochemical leaching, enrichment, and recovery of phosphorus as value-added vivianite from poly-aluminum chloride (PAC) sludge Water Research X Phosphorous recovery PAC sludge Electrochemical leaching Vivianite Sustainability |
| title | Simultaneous electrochemical leaching, enrichment, and recovery of phosphorus as value-added vivianite from poly-aluminum chloride (PAC) sludge |
| title_full | Simultaneous electrochemical leaching, enrichment, and recovery of phosphorus as value-added vivianite from poly-aluminum chloride (PAC) sludge |
| title_fullStr | Simultaneous electrochemical leaching, enrichment, and recovery of phosphorus as value-added vivianite from poly-aluminum chloride (PAC) sludge |
| title_full_unstemmed | Simultaneous electrochemical leaching, enrichment, and recovery of phosphorus as value-added vivianite from poly-aluminum chloride (PAC) sludge |
| title_short | Simultaneous electrochemical leaching, enrichment, and recovery of phosphorus as value-added vivianite from poly-aluminum chloride (PAC) sludge |
| title_sort | simultaneous electrochemical leaching enrichment and recovery of phosphorus as value added vivianite from poly aluminum chloride pac sludge |
| topic | Phosphorous recovery PAC sludge Electrochemical leaching Vivianite Sustainability |
| url | http://www.sciencedirect.com/science/article/pii/S2589914725000362 |
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