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Zhu Y, Duan W, Huang Z, Tian L, Wu W, Dang Z, Feng C. An Anti-Scaling Strategy for Electrochemical Wastewater Treatment: Leveraging Tip-Enhanced Electric Fields. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:13145-13156. [PMID: 38980824 DOI: 10.1021/acs.est.4c03572] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/11/2024]
Abstract
Electrode scaling poses a critical barrier to the adoption of electrochemical processes in wastewater treatment, primarily due to electrode inactivation and increased internal reactor resistance. We introduce an antiscaling strategy using tip-enhanced electric fields to redirect scale-forming compounds (e.g., Mg(OH)2 and CaCO3) from the electrode-electrolyte interface to the bulk solution. Our study utilized Cu nanowires (Cu NW) with high-curvature nanostructures as the cathode, in contrast to Cu nanoparticles (Cu NP), Cu foil (CF), and Cu mesh (CM), to evaluate the electrochemical nitrate reduction reaction (NO3RR) performance in hard water conditions. The Cu NW/CF cathode demonstrated superior NO3RR efficiency, with an apparent rate constant (Kapp) of 1.04 h-1, significantly outperforming control electrodes under identical conditions (Kapp < 0.051 h-1). Through experimental and theoretical analysis, including COMSOL simulations, we show that the high-curvature design of Cu NW induced localized electric field enhancements, propelling OH- ions away from the electrode surface into the bulk solution, thus mitigating scale formation on the cathode. Testing with real nitrate-contaminated wastewater confirms that the Cu NW/CF cathode maintained excellent denitrification efficiency over a 60-day period. This study offers a promising perspective on preventing electrode scaling in electrochemical wastewater treatment, paving the way for more efficient and sustainable practices.
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Affiliation(s)
- Yihui Zhu
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, P. R. China
| | - Weijian Duan
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, P. R. China
| | - Ziyuan Huang
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, P. R. China
| | - Li Tian
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, P. R. China
| | - Wenbo Wu
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, P. R. China
| | - Zhi Dang
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, P. R. China
| | - Chunhua Feng
- The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters, Ministry of Education, School of Environment and Energy, South China University of Technology, Guangzhou 510006, P. R. China
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Zhou J, Chang Y, Yang D, Yang L, Jiang B, Yan W, Xu H, Xu X. A novel membrane-free electrochemical separation-filtering crystallization coupling process for treating circulating cooling water. WATER RESEARCH 2024; 256:121617. [PMID: 38642535 DOI: 10.1016/j.watres.2024.121617] [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: 12/30/2023] [Revised: 03/13/2024] [Accepted: 04/14/2024] [Indexed: 04/22/2024]
Abstract
The traditional electrochemical descaling process exhibits drawbacks, including low OH- utilization efficiency, constrained cathode deposition area, and protracted homogeneous precipitation time. Consequently, this study introduces a novel membrane-free electrochemical separation-filtering crystallization (MFES-FC) coupling process to treat circulating cooling water (CCW). In the membrane-free electrochemical separation (MFES) system, OH- is rapidly extracted by pump suction from the porous cathode boundary layer solution, preventing neutralization with H+, thereby enhancing the removal of Ca2+ and Mg2+. Experimental results indicate that the pH of the pump suction water can swiftly increase from 8.13 to 11.42 within 10 min. Owing to the high supersaturation of the pump suction water, this study couples the MFES with a filtration crystallization (FC) system that employs activated carbon as the medium. This approach captures scale particles to enhance water quality and expedites the homogeneous precipitation of hardness ions, shortening the treatment time while further augmenting the removal rate. After the MFES-FC treatment, the single-pass removal rates for total hardness, Ca2+ hardness, Mg2+ hardness, and alkalinity in the effluent reached 92 %, 97 %, 64 %, and 67 %, respectively, with turbidity of 3 NTU, current efficiency of 86.6 %, and energy consumption of 7.19 kWh·kg-1 CaCO3. This coupling process facilitates an effective removal of hardness and alkalinity at a comparatively low cost, offering a new reference and inspiration for advancements in electrochemical descaling technology.
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Affiliation(s)
- Jie Zhou
- Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Yuexin Chang
- Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Duowen Yang
- Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Liu Yang
- Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Bo Jiang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao 266033, PR China.
| | - Wei Yan
- Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, PR China
| | - Hao Xu
- Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an 710049, PR China; Shandong Shenxin Energy Saving and Environmental Protection Technology Co., Ltd., Industrial Recirculating Water Treatment Engineering Technology Centre of Zaozhuang City, Tengzhou 277531, PR China.
| | - Xing Xu
- Shandong Shenxin Energy Saving and Environmental Protection Technology Co., Ltd., Industrial Recirculating Water Treatment Engineering Technology Centre of Zaozhuang City, Tengzhou 277531, PR China
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Hou J, Li Y, Guo H, Wang Y, He Y, Sun P, Zhao Y, Ni BJ, Zhu T, Liu Y. Efficient electrosynthesis of HO 2- from air for sulfide control in sewers. JOURNAL OF HAZARDOUS MATERIALS 2024; 470:134181. [PMID: 38569343 DOI: 10.1016/j.jhazmat.2024.134181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2024] [Revised: 03/29/2024] [Accepted: 03/30/2024] [Indexed: 04/05/2024]
Abstract
Electrochemically in-situ generation of oxygen and caustic soda is promising for sulfide management while suffers from scaling, poor inactivating capacity, hydrogen release and ammonia escape. In this study, the four-compartment electrochemical cell efficiently captured oxygen molecules from the air chamber to produce HO2- without generating toxic by-products. Meanwhile, the catalyst layer surface of PTFE/CB-GDE maintained a relatively balanced gas-liquid micro-environment, enabling the formation of enduring solid-liquid-gas interfaces for efficient HO2- electrosynthesis. A dramatic increase in HO2- generation rate from 453.3 mg L-1 h-1 to 575.4 mg L-1 h-1 was attained by advancement in operation parameters design (flow channels, electrolyte types, flow rates and circulation types). Stability testing resulted in the HO2- generation rate over 15 g L-1 and the current efficiency (CE) exceeding 85%, indicating a robust stable operational capacity. Furthermore, after 120 mg L-1 HO2- treatment, an increase of 11.1% in necrotic and apoptotic cells in the sewer biofilm was observed, higher than that achieved with the addition of NaOH, H2O2 method. The in-situ electrosynthesis strategy for HO2- represents a significance toward the practical implementation of sulfide abatement in sewers, holding the potential to treat various sulfide-containing wastewater.
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Affiliation(s)
- Jiaqi Hou
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Yiming Li
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Haixiao Guo
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Yufen Wang
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Yanying He
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Peizhe Sun
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Yingxin Zhao
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China
| | - Bing-Jie Ni
- School of Civil and Environmental Engineering, University of New South Wales, Sydney, New South Wales 2052, Australia
| | - Tingting Zhu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China.
| | - Yiwen Liu
- School of Environmental Science and Engineering, Tianjin University, Tianjin 300072, PR China.
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Jiang B, Ren X, Liu Q, Yue X, Yang Q, Liu Y, Xu H, Zhou J. Electrochemical water softening technology: From fundamental research to practical application. WATER RESEARCH 2024; 250:121077. [PMID: 38183800 DOI: 10.1016/j.watres.2023.121077] [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: 10/11/2023] [Revised: 12/25/2023] [Accepted: 12/26/2023] [Indexed: 01/08/2024]
Abstract
In recent decades, the environmentally benign electrochemical softening process has been gaining widespread interest as an emerging alternative for water softening. But, in spite of decades of research, the fundamental advances in laboratory involving electrolytic cell design and treatment system development have not led to urgently needed improvements in industrially practicable electrochemical softening technique. In this review, we firstly provide the critical insights into the mechanism of the currently widely used cathode precipitation process and its inherent limitations, which seriously impede its wide implementation in industry. To relieve the above limitations, some cutting-edge electrochemically homogeneous crystallization systems have been developed, the effectiveness of which are also comprehensively summarized. In addition, the pros and cons between cathode precipitation and electrochemically homogeneous crystallization systems are systematically outlined in terms of performance and economic evaluation, potential application area, and electrolytic cell and system complexity. Finally, we discourse upon practical challenges impeding the industrial-scale deployment of electrochemical water softening technique and highlight the integration of strong engineering sense with fundamental research to realize industry-scale deployment. This review will inspire the researchers and engineers to break the bottlenecks in electrochemical water softening technology and harness this technology with the broadened industrial application area.
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Affiliation(s)
- Bo Jiang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266033, PR China.
| | - Xuanzhen Ren
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266033, PR China
| | - Qiannan Liu
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266033, PR China
| | - Xiao Yue
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266033, PR China
| | - Qipeng Yang
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266033, PR China
| | - Yijie Liu
- School of Environmental and Municipal Engineering, Qingdao University of Technology, Qingdao, 266033, PR China
| | - Hao Xu
- Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, PR China.
| | - Jie Zhou
- Department of Environmental Science and Engineering, Xi'an Jiaotong University, Xi'an, 710049, PR China
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