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Han JH, Bae J, Lim J, Jwa E, Nam JY, Hwang KS, Jeong N, Choi J, Kim H, Jeung YC. Acidification-based direct electrolysis of treated wastewater for hydrogen production and water reuse. Heliyon 2023; 9:e20629. [PMID: 37860540 PMCID: PMC10582299 DOI: 10.1016/j.heliyon.2023.e20629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 09/21/2023] [Accepted: 10/03/2023] [Indexed: 10/21/2023] Open
Abstract
This report describes the direct electrolysis of treated wastewater (as a catholyte) to produce hydrogen and potentially reuse the water. To suppress the negative shift of the cathodic potential due to an increase in pH by the hydrogen evolution reaction (HER), the treated wastewater is acidified using the synergetic effect of protons generated from the bipolar membrane and inorganic precipitation occurred at the surface of the cathode during the HER. Natural seawater, as an accessible source for Mg2+ ions, was added to the treated wastewater because the concentration of Mg2+ ions contained in the original wastewater was too low for acidification to occur. The mixture of treated wastewater with seawater was acidified to pH 3, allowing the initial cathode potential to be maintained for more than 100 h. The amount of inorganic precipitates formed on the cathode surface is greater than that in the control case (adding 0.5 M NaCl instead of seawater) but does not adversely affect the cathodic potential and Faradaic efficiency for H2 production. Additionally, it was confirmed that less organic matter was adsorbed to the inorganic deposits under acidic conditions. These indicate that acidification plays an important role in improving the performance and stability of low-grade water electrolysis. Considering that the treated wastewater is discharged near the ocean, acidification-based electrolysis of the effluent with seawater can be a water reuse technology for green hydrogen production, enhancing water resilience and contributing to the circular economy of water resources.
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Affiliation(s)
- Ji-Hyung Han
- Jeju Global Research Centre, Korea Institute of Energy Research, 200 Haemajihaean-ro, Gujwa-eup, Jeju 63357, Republic of Korea
| | - Jeongwook Bae
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon, 24341, Republic of Korea
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Multidimensional Genomics Research Center, Kangwon National University, Chuncheon, Gangwon, 24341, Republic of Korea
| | - Joohyun Lim
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon, 24341, Republic of Korea
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Multidimensional Genomics Research Center, Kangwon National University, Chuncheon, Gangwon, 24341, Republic of Korea
| | - Eunjin Jwa
- Jeju Global Research Centre, Korea Institute of Energy Research, 200 Haemajihaean-ro, Gujwa-eup, Jeju 63357, Republic of Korea
| | - Joo-Youn Nam
- Jeju Global Research Centre, Korea Institute of Energy Research, 200 Haemajihaean-ro, Gujwa-eup, Jeju 63357, Republic of Korea
| | - Kyo Sik Hwang
- Jeju Global Research Centre, Korea Institute of Energy Research, 200 Haemajihaean-ro, Gujwa-eup, Jeju 63357, Republic of Korea
| | - Namjo Jeong
- Jeju Global Research Centre, Korea Institute of Energy Research, 200 Haemajihaean-ro, Gujwa-eup, Jeju 63357, Republic of Korea
| | - Jiyeon Choi
- Jeju Global Research Centre, Korea Institute of Energy Research, 200 Haemajihaean-ro, Gujwa-eup, Jeju 63357, Republic of Korea
| | - Hanki Kim
- Jeju Global Research Centre, Korea Institute of Energy Research, 200 Haemajihaean-ro, Gujwa-eup, Jeju 63357, Republic of Korea
| | - Youn-Cheul Jeung
- Jeju Global Research Centre, Korea Institute of Energy Research, 200 Haemajihaean-ro, Gujwa-eup, Jeju 63357, Republic of Korea
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Removal of colloidal impurities by thermal softening-coagulation-flocculation-sedimentation in steam assisted gravity drainage (SAGD) produced water: performance, interaction effects and mechanism study. Sep Purif Technol 2023. [DOI: 10.1016/j.seppur.2023.123484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
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Zhang L, Mishra D, Zhang K, Perdicakis B, Pernitsky D, Lu Q. Electrokinetic study of calcium carbonate and magnesium hydroxide particles in lime softening. WATER RESEARCH 2020; 186:116415. [PMID: 32927423 DOI: 10.1016/j.watres.2020.116415] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/27/2020] [Accepted: 09/08/2020] [Indexed: 06/11/2023]
Abstract
Significant effort has been made to measure and understand the surface charge of CaCO3 and Mg(OH)2 particles. Many laboratory experiments have been reported on zeta potential of natural and prepared CaCO3 and a few have also been published for Mg(OH)2, however, there are very few reported measurements of zeta potential of CaCO3 and Mg(OH)2 particles at conditions relevant to lime softening, despite lime softening being a common and established process for water treatment. The present study aims to understand the interactions and electrokinetic properties of these two particles in lime softening. Effects of various experimental parameters such as pH, temperature, aging, inorganic carbon (CO32-/HCO3-), and divalent cations (Ca2+/Mg2+) on the electrokinetic properties (i.e. zeta potential) of CaCO3 and Mg(OH)2 particles were individually studied. The interactions between humic acid (mimicking natural organic matter), silicate (representing silica), clay (mimicking suspended solids) and CaCO3/Mg(OH)2 particles were studied, as well as the interactions between CaCO3 and Mg(OH)2. Thermodynamic modeling was used to predict precipitates as a function of solution chemistry and assist with data interpretation. The results provide considerable insight into factors that are of importance to lime softening.
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Affiliation(s)
- Lu Zhang
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB, T2N 1N4, Canada; Stantec Consulting Inc., 200-325 25 Street SE, Calgary, AB, T2A 7H8, Canada
| | - Dinesh Mishra
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Kailun Zhang
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | | | - David Pernitsky
- Stantec Consulting Inc., 200-325 25 Street SE, Calgary, AB, T2A 7H8, Canada
| | - Qingye Lu
- Department of Chemical and Petroleum Engineering, University of Calgary, Calgary, AB, T2N 1N4, Canada.
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Sun YX, Yang Z, Ye T, Shi N, Tian Y. Evaluation of the treatment of reverse osmosis concentrates from municipal wastewater reclamation by coagulation and granular activated carbon adsorption. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:13543-13553. [PMID: 27032632 DOI: 10.1007/s11356-016-6525-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 03/21/2016] [Indexed: 06/05/2023]
Abstract
Reverse osmosis concentrate (ROC) from municipal wastewater reclamation reverse osmosis (mWRRO) contains elevated concentrations of contaminants which pose potential risks to aquatic environment. The treatment of ROC from an mWRRO using granular activated carbon (GAC) combined pretreatment of coagulation was optimized and evaluated. Among the three coagulants tested, ferric chloride (FeCl3) presented relatively higher DOC removal efficiency than polyaluminium chloride and lime at the same dosage and coagulation conditions. The removal efficiency of DOC, genotoxicity, and antiestrogenic activity concentration of the ROC could achieve 16.9, 18.9, and 39.7 %, respectively, by FeCl3 coagulation (with FeCl3 dosage of 180.22 mg/L), which can hardly reduce UV254 and genotoxicity normalized by DOC of the DOM with MW <5 kDa. However, the post-GAC adsorption column (with filtration velocity of 5.7 m/h, breakthrough point adsorption capacity of 0.22 mg DOC/g GAC) exhibited excellent removal efficiency on the dominant DOM fraction of MW <5 kDa in the ROC. The removal efficiency of DOC, UV254, and TDS in the ROC was up to 91.8, 96, and 76.5 %, respectively, by the FeCl3 coagulation and post-GAC adsorption. Also, the DOM with both genotoxicity and antiestrogenic activity were completely eliminated by the GAC adsorption. The results suggest that GAC adsorption combined pretreatment of FeCl3 coagulation as an efficient method to control organics, genotoxicity, and antiestrogenic activity in the ROC from mWRRO system.
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Affiliation(s)
- Ying-Xue Sun
- Department of Environmental Science and Engineering, Beijing Technology and Business University, Beijing, 100048, People's Republic of China.
| | - Zhe Yang
- Department of Environmental Science and Engineering, Beijing Technology and Business University, Beijing, 100048, People's Republic of China
| | - Tao Ye
- Department of Civil and Environmental Engineering, The George Washington University, Washington, DC, 20052, USA
| | - Na Shi
- Department of Environmental Science and Engineering, Beijing Technology and Business University, Beijing, 100048, People's Republic of China
| | - Yuan Tian
- Department of Environmental Science and Engineering, Beijing Technology and Business University, Beijing, 100048, People's Republic of China
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Comstock SEH, Boyer TH, Graf KC. Treatment of nanofiltration and reverse osmosis concentrates: comparison of precipitative softening, coagulation, and anion exchange. WATER RESEARCH 2011; 45:4855-4865. [PMID: 21774956 DOI: 10.1016/j.watres.2011.06.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2010] [Revised: 05/16/2011] [Accepted: 06/23/2011] [Indexed: 05/31/2023]
Abstract
Disposal and treatment of concentrate from nanofiltration (NF) and reverse osmosis (RO) are major challenges to implementing membrane treatment processes. Intermediate treatment of membrane concentrate, between primary and secondary membrane stages, has the potential to increase membrane recovery rates and decrease the volume of concentrate produced. To achieve this, however, there is a need to better understand treatment of membrane concentrate. As a result, this work systematically evaluated lime softening, ferric sulfate coagulation, and magnetic ion exchange (MIEX) as individual, intermediate treatment processes for membrane concentrate. Six membrane concentrates, from NF and RO, with varying concentrations of calcium, dissolved organic matter (DOM), and sulfate were chosen for this study. Maximum removal of calcium was achieved by lime softening, whereas maximum removals of DOM and sulfate were achieved by MIEX. The results of this work show that intermediate treatment of NF/RO concentrate is capable of producing treated concentrate with water quality approximately equal to the initial source water.
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Affiliation(s)
- Sarah E H Comstock
- Department of Environmental Engineering Sciences, University of Florida, P.O. Box 116450, Gainesville, FL 32611-6450, USA
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Russell CG, Lawler DF, Speitel GE, Katz LE. Effect of softening precipitate composition and surface characteristics on natural organic matter adsorption. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2009; 43:7837-7842. [PMID: 19921902 DOI: 10.1021/es900991n] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Natural organic matter (NOM) removal during water softening is thought to occur through adsorption onto or coprecipitation with calcium and magnesium solids. However, details of precipitate composition and surface chemistry and subsequent interactions with NOM are relatively unknown. In this study, zeta potentiometry analyses of precipitates formed from inorganic solutions under varying conditions (e.g., Ca-only, Mg-only, Ca + Mg, increasing lime or NaOH dose) indicated that both CaCO3 and Mg(OH)2 were positively charged at higher lime (Ca(OH)2) and NaOH doses (associated with pH values above 11.5), potentially yielding a greater affinity for adsorbing negatively charged organic molecules. Environmental scanning electron microscopy (ESEM) images of CaCO3 solids illustrated the rhombohedral shape characteristic of calcite. In the presence of increasing concentrations of magnesium, the CaCO3 rhombs shifted to more elongated crystals. The CaCO3 solids also exhibited increasingly positive surface charge from Mg incorporation into the crystal lattice, potentially creating more favorable conditions for adsorption of organic matter. NOM adsorption experiments using humic substances extracted from Lake Austin and Missouri River water elucidated the role of surface charge and surface area on adsorption.
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Affiliation(s)
- Caroline G Russell
- The University of Texas at Austin, Department of Civil, Architectural, and Environmental Engineering, Austin, Texas 78712, USA.
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