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Wang Z, Yang Z, Chen YF. Pore-scale investigation of surfactant-enhanced DNAPL mobilization and solubilization. CHEMOSPHERE 2023; 341:140071. [PMID: 37673186 DOI: 10.1016/j.chemosphere.2023.140071] [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: 01/04/2023] [Revised: 07/20/2023] [Accepted: 09/04/2023] [Indexed: 09/08/2023]
Abstract
Surfactant-enhanced aquifer remediation has been proved successful to remove dense non-aqueous phase liquids (DNAPLs) from contaminated sites. However, the underlying mechanisms of the DNAPL mobilization and solubilization at the pore scale remains to be addressed for efficient application to the field remediation system. In this work, the emerging microfluidic and imaging technologies are applied to investigate the dynamics of DNAPL remediation. Visualized experiments of the evolution of DNAPL remediation are performed to study the role of surfactant type, concentration and injection rate. The DNAPL remediation is dominated by mobilization followed by solubilization for most surfactants. Mobilization occurs as soon as surfactants and DNAPL are in contact until forming a new stable phase structure, and the solubilization continues until the end of injection. We observe the breakup behavior of long droplets and ganglia during the mobilization, which is attributed to the surfactant-reduced interfacial tension and thus expedites DNAPL mobilization and redistribution. During the solubilization, the formation of micelles incorporating DNAPL fractions increases the DNAPL concentration gradient and thus enhances the mass transfer, but the rate-limited diffusion of micelles reduces the mass transfer rate coefficient. Increasing the surfactant content and decreasing the injection rate can promote mobilization and solubilization. The DNAPL mobilization ability of the surfactants SDS and SDBS is stronger than SAOS and Tween 80 regardless of the injection rates. Tween 80 may be considered an ideal surfactant of only solubilization but not mobilization is desired. This work elucidates the pore-scale mechanisms during surfactant-enhanced DNAPL remediation, which are beneficial for upscaling studies, predictive modeling, and operation optimization of DNAPL remediation in the field.
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Affiliation(s)
- Zejun Wang
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan, 430072, China; Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering of the Ministry of Education, Wuhan University, Wuhan, 430072, China
| | - Zhibing Yang
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan, 430072, China; Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering of the Ministry of Education, Wuhan University, Wuhan, 430072, China.
| | - Yi-Feng Chen
- State Key Laboratory of Water Resources Engineering and Management, Wuhan University, Wuhan, 430072, China; Key Laboratory of Rock Mechanics in Hydraulic Structural Engineering of the Ministry of Education, Wuhan University, Wuhan, 430072, China
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Decontamination of water co-polluted by copper, toluene and tetrahydrofuran using lauric acid. Sci Rep 2022; 12:15832. [PMID: 36138091 PMCID: PMC9500063 DOI: 10.1038/s41598-022-20241-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 09/12/2022] [Indexed: 11/17/2022] Open
Abstract
Co-contamination by organic solvents (e.g., toluene and tetrahydrofuran) and metal ions (e.g., Cu2+) is common in industrial wastewater and in industrial sites. This manuscript describes the separation of THF from water in the absence of copper ions, as well as the treatment of water co-polluted with either THF and copper, or toluene and copper. Tetrahydrofuran (THF) and water are freely miscible in the absence of lauric acid. Lauric acid separates the two solvents, as demonstrated by proton nuclear magnetic resonance (1H NMR) and Attenuated Total Reflection-Fourier Transform Infrared Spectroscopy (ATR-FTIR). The purity of the water phase separated from 3:7 (v/v) THF:water mixtures using 1 M lauric acid is ≈87%v/v. Synchrotron small angle X-Ray scattering (SAXS) indicates that lauric acid forms reverse micelles in THF, which swell in the presence of water (to host water in their interior) and ultimately lead to two free phases: 1) THF-rich and 2) water-rich. Deprotonated lauric acid (laurate ions) also induces the migration of Cu2+ ions in either THF (following separation from water) or in toluene (immiscible in water), enabling their removal from water. Laurate ions and copper ions likely interact through physical interactions (e.g., electrostatic interactions) rather than chemical bonds, as shown by ATR-FTIR. Inductively coupled plasma—optical emission spectrometry (ICP-OES) demonstrates up to 60% removal of Cu2+ ions from water co-polluted by CuSO4 or CuCl2 and toluene. While lauric acid emulsifies water and toluene in the absence of copper ions, copper salts destabilize emulsions. This is beneficial, to avoid that copper ions are re-entrained in the water phase alongside with toluene, following their migration in the toluene phase. The effect of copper ions on emulsion stability is explained based on the decreased interfacial activity and compressional rigidity of interfacial films, probed using a Langmuir trough. In wastewater treatment, lauric acid (a powder) can be mixed directly in the polluted water. In the context of groundwater remediation, lauric acid can be solubilized in canola oil to enable its injection to treat aquifers co-polluted by organic solvents and Cu2+. In this application, injectable filters obtained by injecting cationic hydroxyethylcellulose (HEC +) would impede the flow of toluene and copper ions partitioned in it, protecting downstream receptors. Co-contaminants can be subsequently extracted upstream of the filters (using pumping wells), to enable their simultaneous removal from aquifers.
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Xu JC, Yang LH, Yuan JX, Li SQ, Peng KM, Lu LJ, Huang XF, Liu J. Coupling surfactants with ISCO for remediating of NAPLs: Recent progress and application challenges. CHEMOSPHERE 2022; 303:135004. [PMID: 35598784 DOI: 10.1016/j.chemosphere.2022.135004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 05/10/2022] [Accepted: 05/14/2022] [Indexed: 06/15/2023]
Abstract
Non-aqueous phase liquids (NAPLs) pose a serious risk to the soil-groundwater environment. Coupling surfactants with in situ chemical oxidation (ISCO) technology is a promising strategy, which is attributed to the enhanced desorption and solubilization efficiency of NAPL contaminants. However, the complex interactions among surfactants, oxidation systems, and NAPL contaminants have not been fully revealed. This review provides a comprehensive overview on the development of surfactant-coupled ISCO technology focusing on the effects of surfactants on oxidation systems and NAPLs degradation behavior. Specifically, we discussed the compatibility between surfactants and oxidation systems, including the non-productive consumption of oxidants by surfactants, the role of surfactants in catalytic oxidation systems, and the loss of surfactants solubilization capacity during oxidation process. The effect of surfactants on the degradation behavior of NAPL contaminants is then thoroughly summarized in terms of degradation kinetics, byproducts and degradation mechanisms. This review demonstrates that it is crucial to minimize the negative effects of surfactants on NAPL contaminants oxidation process by fully understanding the interaction between surfactants and oxidation systems, which would promote the successful implementation of surfactant-coupled ISCO technology in remediation of NAPLs-contaminated sites.
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Affiliation(s)
- Jing-Cheng Xu
- College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Ministry of Education Key Laboratory of Yangtze River Water Environment, Shanghai Institute of Pollution Control and Ecological Security, Tongji University, Shanghai, 200092, China
| | - Li-Heng Yang
- College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Ministry of Education Key Laboratory of Yangtze River Water Environment, Shanghai Institute of Pollution Control and Ecological Security, Tongji University, Shanghai, 200092, China
| | - Jing-Xi Yuan
- College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Ministry of Education Key Laboratory of Yangtze River Water Environment, Shanghai Institute of Pollution Control and Ecological Security, Tongji University, Shanghai, 200092, China
| | - Shuang-Qiang Li
- College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Ministry of Education Key Laboratory of Yangtze River Water Environment, Shanghai Institute of Pollution Control and Ecological Security, Tongji University, Shanghai, 200092, China
| | - Kai-Ming Peng
- College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Ministry of Education Key Laboratory of Yangtze River Water Environment, Shanghai Institute of Pollution Control and Ecological Security, Tongji University, Shanghai, 200092, China
| | - Li-Jun Lu
- College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Ministry of Education Key Laboratory of Yangtze River Water Environment, Shanghai Institute of Pollution Control and Ecological Security, Tongji University, Shanghai, 200092, China
| | - Xiang-Feng Huang
- College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Ministry of Education Key Laboratory of Yangtze River Water Environment, Shanghai Institute of Pollution Control and Ecological Security, Tongji University, Shanghai, 200092, China; Frontiers Science Center for Intelligent Autonomous Systems, Shanghai, 201210, China
| | - Jia Liu
- College of Environmental Science and Engineering, State Key Laboratory of Pollution Control and Resource Reuse, Ministry of Education Key Laboratory of Yangtze River Water Environment, Shanghai Institute of Pollution Control and Ecological Security, Tongji University, Shanghai, 200092, China; Frontiers Science Center for Intelligent Autonomous Systems, Shanghai, 201210, China.
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Ritoré E, Coquelet B, Arnaiz C, Morillo J, Usero J. Guidelines for surfactant selection to treat petroleum hydrocarbon-contaminated soils. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2022; 29:7639-7651. [PMID: 34480306 PMCID: PMC8763727 DOI: 10.1007/s11356-021-15876-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2021] [Accepted: 08/05/2021] [Indexed: 05/11/2023]
Abstract
The present study determined the most effective surfactants to remediate gasoline and diesel-contaminated soil integrating information from soil texture and soil organic matter. Different ranges for aliphatic and aromatic hydrocarbons (> C6-C8, > C8-C10, > C10-C12, > C12-C16, > C16-C21, and > C21-C35) in gasoline and diesel fuel were analyzed. This type of analysis has been investigated infrequently. Three types of soils (silty clay, silt loam, and loamy sand) and four surfactants (non-ionic: Brij 35 and Tween 80; anionic: SDBS and SDS) were used. The results indicated that the largest hydrocarbon desorption was 56% for silty clay soil (SDS), 59% for silt loam soil (SDBS), and 69% for loamy sand soil (SDS). Soils with large amounts of small particles showed the worst desorption efficiencies. Anionic surfactants removed more hydrocarbons than non-ionic surfactants. It was notable that preferential desorption on different hydrocarbon ranges was observed since aliphatic hydrocarbons and large ranges were the most recalcitrant compounds of gasoline and diesel fuel components. Unlike soil texture, natural organic matter concentration caused minor changes in the hydrocarbon removal rates. Based on these results, this study might be useful as a tool to select the most cost-effective surfactant knowing the soil texture and the size and chemical structure of the hydrocarbons present in a contaminated site.
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Affiliation(s)
- Emilio Ritoré
- Departamento de Ingeniería Química y Ambiental, Escuela Técnica Superior de Ingeniería, Universidad de Sevilla, Camino de los Descubrimientos, s/n, 41092, Sevilla, Spain.
| | - Bruno Coquelet
- Inerco, Inspección y control S.A., La Cartuja Science and Technology Park, Calle Tomás Alva Edison, 2, 41092, Sevilla, Spain
| | - Carmen Arnaiz
- Departamento de Ingeniería Química y Ambiental, Escuela Técnica Superior de Ingeniería, Universidad de Sevilla, Camino de los Descubrimientos, s/n, 41092, Sevilla, Spain
| | - José Morillo
- Departamento de Ingeniería Química y Ambiental, Escuela Técnica Superior de Ingeniería, Universidad de Sevilla, Camino de los Descubrimientos, s/n, 41092, Sevilla, Spain
| | - José Usero
- Departamento de Ingeniería Química y Ambiental, Escuela Técnica Superior de Ingeniería, Universidad de Sevilla, Camino de los Descubrimientos, s/n, 41092, Sevilla, Spain
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Bajagain R, Gautam P, Jeong SW. Degradation of petroleum hydrocarbons in unsaturated soil and effects on subsequent biodegradation by potassium permanganate. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH 2020; 42:1705-1714. [PMID: 31197553 DOI: 10.1007/s10653-019-00346-y] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Accepted: 06/05/2019] [Indexed: 06/09/2023]
Abstract
To date, the oxidation of petroleum hydrocarbons using permanganate has been investigated rarely. Only a few studies on the remediation of unsaturated soil using permanganate can be found in the literature. This is, to the best of our knowledge, the first study conducted using permanganate pretreatment to degrade petroleum hydrocarbons in unsaturated soil in combination with subsequent bioaugmentation. The pretreatment of diesel-contaminated unsaturated soil with 0.5-pore-volume (5%) potassium permanganate (PP) by solution pouring and foam spraying (with a surfactant) achieved the total petroleum hydrocarbon (TPH) removal efficiencies of 37% and 72.1%, respectively. The PP foam, when coupled with bioaugmentation foam, further degraded the TPH to a final concentration of 438 mg/kg (92.1% total reduction). The experiment was conducted without soil mixing or disturbance. The relatively high TPH removal efficiency achieved by the PP-bioaugmentation serial foam application may be attributed to an increase in soil pH caused by the PP and effective infiltration of the remediation agent by foaming. The applied PP foam increased the pH of the acidic soil, thus enhancing microbial activity. The first-order biodegradation rate after PP oxidation was calculated to be 0.068 d-1. Furthermore, 94% of the group of relatively persistent hydrocarbons (C18-C22) was removed by PP-bioaugmentation, as verified by chromatogram peaks. Some physicochemical parameters related to contaminant removal efficiency were also evaluated. The results reveal that PP can degrade soil TPH and significantly enhance the biodegradation rate in unsaturated diesel-contaminated soil when combined with bioaugmentation foam.
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Affiliation(s)
- Rishikesh Bajagain
- Department of Environmental Engineering, Kunsan National University, Kunsan, 54150, South Korea
| | - Prakash Gautam
- Department of Environmental Engineering, Kunsan National University, Kunsan, 54150, South Korea
| | - Seung-Woo Jeong
- Department of Environmental Engineering, Kunsan National University, Kunsan, 54150, South Korea.
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Lamont K, Marangoni AG, Pensini E. 'Emulsion locks' for the containment of hydrocarbons during surfactant flushing. J Environ Sci (China) 2020; 90:98-109. [PMID: 32081345 DOI: 10.1016/j.jes.2019.11.021] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Revised: 11/28/2019] [Accepted: 11/28/2019] [Indexed: 06/10/2023]
Abstract
Reversible double water in oil in water (W/O/W) emulsions were developed to contain subsurface hydrocarbon spills during their remediation using surfactant flushing. Double emulsions were prepared by emulsifying CaCl2 solutions in canola oil, and subsequently by emulsifying the W/O emulsions in aqueous sodium alginate solutions. The formation of double emulsions was confirmed with confocal and optical microscopy. The double emulsions reversed and gelled when mixed with the surfactants sodium dodecyl sulfate (SDS) and cocamidopropyl betaine (CPB). Gels can act as 'emulsion locks' to prevent spreading of the hydrocarbon plume from the areas treated with surfactant flushing, as shown in sand column tests. Shear rheology was used to quantify the viscoelastic moduli increase (gelation) upon mixing the double emulsion with SDS and CPB. SDS was more effective than CPB in gelling the double emulsions. CPB and SDS could adsorb at the interface between water and model hydrocarbons (toluene and motor oil), lowering the interfacial tension and rigidifying the interface (as shown with a Langmuir trough). Bottle tests and optical microscopy showed that SDS and CPB produced W/O and O/W emulsions, with either toluene or motor oil and water. The emulsification of motor oil and toluene in water with SDS and CPB facilitated their flow through sand columns and their recovery. Toluene recovery from sand columns was quantitated using Gas-Chromatography Mass-Spectroscopy (GC-MS). The data show that SDS and CPB can be used both for surfactant flushing and to trigger the gelation of 'emulsion locks'. Ethanol also gelled the emulsions at 100 mL/L.
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Affiliation(s)
- Kristine Lamont
- University of Guelph, School of Engineering, 50 Stone Road East, Guelph ON, N1G 2W1, Canada
| | - Alejandro G Marangoni
- University of Guelph, Food Science Department, 50 Stone Road East, Guelph ON, N1G 2W1, Canada
| | - Erica Pensini
- University of Guelph, School of Engineering, 50 Stone Road East, Guelph ON, N1G 2W1, Canada.
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Martel R, Portois C, Robert T, Uyeda M. Etched glass micromodel for laboratory simulation of NAPL recovery mechanisms by surfactant solutions in fractured rock. JOURNAL OF CONTAMINANT HYDROLOGY 2019; 227:103550. [PMID: 31493908 DOI: 10.1016/j.jconhyd.2019.103550] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 08/21/2019] [Accepted: 08/28/2019] [Indexed: 06/10/2023]
Abstract
Fractured porous media receive less attention than classic porous media in terms of remediation processes and sui` techniques that can be applied efficiently. An etched glass micromodel was built in order to simulate a fractured bedrock. The purpose of this paper was to evaluate the feasibility of surfactant-alcohol injection to recover NAPL with this fractured glass micromodel. The influence of several parameters influencing NAPL recovery via surfactant injection were tested in the micromodel: the ratio of alcohol to surfactant, the total concentration of active matter (alcohol + surfactant), the number of pore volume injected, the direction of the injection, and the continuous or pulsed injection mode. These tests made it possible to identify the key parameters for a better recovery of NAPL in a fractured environment, which are: continuous upward injection, six pore volume of surfactant solution and a n-AmOH/n-BuOH ratio of 2.5. Micromodel experiments were compared to previous reported experiments using the same surfactant solutions injected in classical porous media. The lower capillary number being required for NAPL recovery in porous media is probably related to the better sweep and the increase in surface area available for NAPL dissolution. NAPL recovery may be improved by increasing the capillary number by increasing the injected surfactant solution viscosity with polymer or by injecting foam.
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Affiliation(s)
- Richard Martel
- Centre Eau Terre Environnement, Institut national de la recherche scientifique (INRS), 490 rue de la Couronne, Québec G1K 9A9, Canada.
| | - Clément Portois
- Centre Eau Terre Environnement, Institut national de la recherche scientifique (INRS), 490 rue de la Couronne, Québec G1K 9A9, Canada
| | - Thomas Robert
- Centre Eau Terre Environnement, Institut national de la recherche scientifique (INRS), 490 rue de la Couronne, Québec G1K 9A9, Canada
| | - Michelle Uyeda
- Jacobs Engineering Ltd, 4720 Kingsway Suite 2100, Burnaby, BC V5H4N2, Canada
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Lamont K, Pensini E, Marangoni AG. Gelation on demand using switchable double emulsions: A potential strategy for the in situ immobilization of organic contaminants. J Colloid Interface Sci 2019; 562:470-482. [PMID: 31785939 DOI: 10.1016/j.jcis.2019.11.090] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Revised: 11/06/2019] [Accepted: 11/20/2019] [Indexed: 12/31/2022]
Abstract
Switchable double emulsions (water in oil in water, W/O/W) are proposed for the in situ immobilization of subsurface organic contaminants such as toluene, hexane or benzene. Primary W/O emulsions were prepared by emulsifying 250 mL of 0.36 M CaCl2 aqueous solutions in 1 L of canola oil (with 12.5 g/L of ethylcellulose, EC, and 2.5 g/L of calcium stearate). In the primary W/O emulsion the water droplets in oil were ≈8 μm, as observed using an optical and a confocal microscope. EC and calcium stearate adsorbed at the oil water interface (as demonstrated by interfacial tension measurements), forming films which stabilized the W/O emulsions (as verified with bottle tests). Experiments conducted using a Langmuir trough suggest that EC and calcium stearate films did not desorb from the oil-water interface upon compression. Crumpling tests and optical microscopy observations indicate that EC and calcium stearate films were skin-like, and buckled when deformed. To obtain double W/O/W emulsions the primary emulsions were emulsified in a 0.75 wt% solution of sodium alginate, with 2 mL/L of Tween 20 and 10 g/L of NaCl. The formation of W/O/W emulsions was verified through optical microscopy and confocal microscopy observations. In the absence of the contaminants the double emulsions were stable, as observed by resting them on the bench over three days and agitating them with a multi-action wrist shaker for 30 min. Also, they had low shear elastic (G' = 2.67 ± 0.58 Pa) and viscous (G″ = 1.69 ± 0.24 Pa) moduli, which should facilitate their transport through geological media (e.g. soil) to polluted areas. Upon mixing with toluene, hexane or benzene at concentrations ranging from 5% to 17%, the double emulsions were destabilized. Emulsion destabilization caused the release of CaCl2, which crosslinked sodium alginate and formed gels in which the contaminants were incorporated. The gelation rate and the magnitude of the viscoelastic moduli depended on the contaminant type and concentration, and on the mixing time. Gelation occurred fastest with the highest toluene concentrations tested (9% to 17%), but the highest elastic moduli were measured with 9% toluene concentrations for the longest mixing times tested (90 s). Gelation occurred slowest with hexane, likely due to the poor solubility of EC in hexane. Because of their ability to gel exclusively in contaminant proximity, the double emulsions studied offer a potential strategy to control the migration of plumes of contaminants such as toluene, hexane or benzene.
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Affiliation(s)
- Kristine Lamont
- University of Guelph, School of Engineering, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
| | - Erica Pensini
- University of Guelph, School of Engineering, 50 Stone Road East, Guelph, ON N1G 2W1, Canada.
| | - Alejandro G Marangoni
- University of Guelph, Food Science Department, 50 Stone Road East, Guelph, ON N1G 2W1, Canada
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Yang ZH, Ou JH, Dong CD, Chen CW, Lin WH, Kao CM. Remediation of TCE-contaminated groundwater using KMnO 4 oxidation: laboratory and field-scale studies. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:34027-34038. [PMID: 30232775 DOI: 10.1007/s11356-018-3099-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 08/28/2018] [Indexed: 06/08/2023]
Abstract
The objectives of this study were to (1) conduct laboratory bench and column experiments to determine the oxidation kinetics and optimal operational parameters for trichloroethene (TCE)-contaminated groundwater remediation using potassium permanganate (KMnO4) as oxidant and (2) to conduct a pilot-scale study to assess the efficiency of TCE remediation by KMnO4 oxidation. The controlling factors in laboratory studies included soil oxidant demand (SOD), molar ratios of KMnO4 to TCE, KMnO4 decay rate, and molar ratios of Na2HPO4 to KMnO4 for manganese dioxide (MnO2) production control. Results show that a significant amount of KMnO4 was depleted when it was added in a soil/water system due to the existence of natural soil organic matters. The presence of natural organic material in soils can exert a significant oxidant demand thereby reducing the amount of KMnO4 available for the destruction of TCE as well as the overall oxidation rate of TCE. Supplement of higher concentrations of KMnO4 is required in the soil systems with high SOD values. Higher KMnO4 application resulted in more significant H+ and subsequent pH drop. The addition of Na2HPO4 could minimize the amount of produced MnO2 particles and prevent the clogging of soil pores, and TCE oxidation efficiency would not be affected by Na2HPO4. To obtain a complete TCE removal, the amount of KMnO4 used to oxidize TCE needs to be higher than the theoretical molar ratio of KMnO4 to TCE based on the stoichiometry equation. Relatively lower oxidation rates are obtained with lower initial TCE concentrations. The half-life of TCE decreased with increased KMnO4 concentrations. Results from the pilot-scale study indicate that a significant KMnO4 decay occurs after the injection due to the reaction of KMnO4 with soil organic matters, and thus, the amount of KMnO4, which could be transported from the injection point to the downgradient area, would be low. The effective influence zone of the KMnO4 oxidation was limited to the KMnO4 injection area (within a 3-m radius zone). Migration of KMnO4 to farther downgradient area was limited due to the reaction of KMnO4 to natural organic matters. To retain a higher TCE removal efficiency, continuous supplement of high concentrations of KMnO4 is required. The findings would be useful in designing an in situ field-scale ISCO system for TCE-contaminated groundwater remediation using KMnO4 as the oxidant.
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Affiliation(s)
- Zong-Han Yang
- Apollo Technology Co., Ltd., Kaohsiung City, 80248, Taiwan
| | - Jiun-Hau Ou
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung City, 80424, Taiwan
| | - Cheng-Di Dong
- Department of Marine Environmental Engineering, National Kaohsiung Marine University, Kaohsiung City, 81157, Taiwan
| | - Chiu-Wen Chen
- Department of Marine Environmental Engineering, National Kaohsiung Marine University, Kaohsiung City, 81157, Taiwan
| | - Wei-Han Lin
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung City, 80424, Taiwan
| | - Chih-Ming Kao
- Institute of Environmental Engineering, National Sun Yat-Sen University, Kaohsiung City, 80424, Taiwan.
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Xie Q, Mumford KG, Kueper BH, Zhao C. A numerical model for estimating the removal of volatile organic compounds in laboratory-scale treatability tests for thermal treatment of NAPL-impacted soils. JOURNAL OF CONTAMINANT HYDROLOGY 2019; 226:103526. [PMID: 31437717 DOI: 10.1016/j.jconhyd.2019.103526] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Revised: 05/28/2019] [Accepted: 07/20/2019] [Indexed: 06/10/2023]
Abstract
Treatability tests can be carried out to assess the potential effectiveness of thermal treatment technologies under different site conditions and are important for specific technology selection and design. In order to reduce the costs for laboratory tests and expand the insights from previous treatability studies, a one-dimensional (1D) radial finite difference model was developed to simulate the removal of volatile organic compounds (VOCs) in laboratory thermal treatability tests. The processes considered in the model include heat conduction, co-boiling of single-component or multi-component NAPLs with water, and water boiling. An explicit approach is used to simulate the evolution of NAPL composition for multi-component NAPLs during heating. The developed model adopts only two fitting parameters and was calibrated and validated using previous laboratory experiments. In this paper, the developed model was first calibrated to three laboratory experiments using temperature measurements, which resulted in matches to the NAPL and gas saturations. After calibration, the model was able to predict the temperature, NAPL and gas saturations for the remaining seven experiments, including those with single and multi-component NAPLs, using the average value of each fitting parameter.
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Affiliation(s)
- Qianli Xie
- Department of Civil Engineering, Queen's University, Kingston, ON K7L 3N6, Canada.
| | - Kevin G Mumford
- Department of Civil Engineering, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Bernard H Kueper
- Department of Civil Engineering, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Chen Zhao
- Morrison Hershfield, 2400 Don Reid Drive, Ottawa, ON K1H 1E1, Canada
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Luo J, Yang D, Qi S, Wu J, Gu XS. Using solar cell to phytoremediate field-scale metal polluted soil assisted by electric field. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 165:404-410. [PMID: 30218963 DOI: 10.1016/j.ecoenv.2018.09.031] [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: 06/14/2018] [Revised: 09/04/2018] [Accepted: 09/06/2018] [Indexed: 06/08/2023]
Abstract
Eucalyptus globulus were used to remediate a real scale site endangered by e-waste with electric fields supplied by solar cell and conventional storage battery. The capacity of the species to produce biomass, absorb pollutants and decontaminate metals, as well as the soil moisture of various layers under different treatments was compared. During the 3-month experiment, the output potential of solar cell influenced by weather conditions was less stable (ranging from 0 to 8.3 V) comparing with traditional power supply. Solar cell and storage battery stimulated the growth of the species from 5.92 in control to 7.21 and 7.38 kg per plant, respectively, demonstrating their similar improvement effect. Electric fields of either power source increased the metal concentrations of plant roots and shoots in equal proportions and subsequently greatly promoted the efficiency to decontaminate pollutants. Relative to the control without electric field, solar cell and storage battery treatments reduced the soil moisture of each corresponding layer and consequently, alleviated the leaching risk. At the termination of the experiment, metals tended to distribute in the surface layer under electric field assisted phytoremediation either by solar cell or storage battery. Comparing with conventional battery, solar cell has similar effect on improving remediation and mitigating leaching risk, but is less energy consuming and easier to manage, especially under real scale field. Solar cell treatment was suggested to be a suitable supplementary means to improve phytoremediation efficiency.
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Affiliation(s)
- Jie Luo
- College of Resources and Environment, Yangtze University, Wuhan, China.
| | - Dan Yang
- China University of Geosciences, Wuhan 430074, China
| | - Shihua Qi
- China University of Geosciences, Wuhan 430074, China
| | - Jian Wu
- China University of Geosciences, Wuhan 430074, China
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12
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Chao HP, Wang YC, Tran HN. Removal of hexavalent chromium from groundwater by Mg/Al-layered double hydroxides using characteristics of in-situ synthesis. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 243:620-629. [PMID: 30218872 DOI: 10.1016/j.envpol.2018.08.033] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 07/29/2018] [Accepted: 08/11/2018] [Indexed: 06/08/2023]
Abstract
This study aimed to develop a novel in-situ method to directly remove toxic hexavalent chromium anions from groundwater. The characteristics of Mg/Al-layered double hydroxides (LDH) involving in-situ synthesis and interlayer exchangeable anions can facilitate to remove Cr(VI) from solution. Two different methods of LDH preparation were employed to explore the adsorption efficiency of (di)chromates, such as traditional coprecipitation (CO3-LDH) and innovative in-situ synthesis (in-situ-LDH). The synthesized LDH samples were characterized using scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and zeta potential. The results demonstrated that the adsorptive amount of Cr(VI) for the in-situ synthesis process dramatically increased with an increase in initial Cr(VI) concentrations from 100 mg/L to 900 mg/L. The kinetic study indicated that the constant rate (k2) of the pseudo-second-order equation significantly decreased when the initial concentration of Cr(VI) exceeded 500 mg/L. The removal efficiency of Cr(VI) was slightly dependent on solution pH (5.0-12) values. The in-situ-LDH absorbent (339 mg/g) exhibited the significantly higher Langmuir maximum adsorption capacity than CO3-LDH (246 mg/g). The primary adsorption mechanism was anion exchange; meanwhile, the adsorption-coupled reduction mechanism also played an integral role. The advanced in-situ synthetic method can be developed to efficiently remove toxic hexavalent chromium anions from groundwater.
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Affiliation(s)
- Huan-Ping Chao
- Department of Environmental Engineering, Chung Yuan Christian University, Chung-Li, 32023, Taiwan.
| | - Yu-Chun Wang
- Department of Environmental Engineering, Chung Yuan Christian University, Chung-Li, 32023, Taiwan
| | - Hai Nguyen Tran
- Institute of Research and Development, Duy Tan University, Da Nang, 550000, Vietnam.
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13
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Sheng Y, Zhang X, Zhai X, Zhang F, Li G, Zhang D. A mobile, modular and rapidly-acting treatment system for optimizing and improving the removal of non-aqueous phase liquids (NAPLs) in groundwater. JOURNAL OF HAZARDOUS MATERIALS 2018; 360:639-650. [PMID: 30153629 DOI: 10.1016/j.jhazmat.2018.08.044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2018] [Revised: 08/02/2018] [Accepted: 08/12/2018] [Indexed: 06/08/2023]
Abstract
Non-aqueous phase liquids (NAPLs) in pumped groundwater are highly variable, challenging the selection of above-ground treatment strategies in pump-and-treat system. Adjustable systems with multiple treatment units are urgently required. In the present study, a mobile, modular and rapidly-acting treatment system was developed to treat groundwater contaminated by NAPLs at a chemical industrial site. The system integrated four units of coagulation sedimentation, air flotation, air stripping and chemical oxidation. During a 3-month onsite operation, the composition of groundwater NAPLs had huge fluctuations and different treatment units had unique advantages in eliminating some components. For instance, air stripping exhibited satisfactory removal efficiencies (>80%) for short-chain petroleum hydrocarbons and chloroalkanes, but poor performance for others comparing to other units. A decision-making tool and a central control system were further developed to combine and adjust the four units in proper orders, achieving satisfied removal efficiency (70-90%) for multi-component NAPLs, regardless of composition fluctuation. These findings raise the state-of-the-art modular and rapidly-acting groundwater treatment system to clean up NAPLs contaminated groundwater through pump-and-treat strategy, help in better understanding on the decision and management to improve the treatment performance, and provide guidelines for its implication at other sites contaminated with multi-component NAPLs or undergoing accidental contamination.
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Affiliation(s)
- Yizhi Sheng
- School of Environment, Tsinghua University, Beijing 100084, China; State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China
| | - Xu Zhang
- School of Environment, Tsinghua University, Beijing 100084, China; State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China
| | - Xiaobo Zhai
- School of Environment, Tsinghua University, Beijing 100084, China
| | - Fang Zhang
- School of Environment, Tsinghua University, Beijing 100084, China; State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China
| | - Guanghe Li
- School of Environment, Tsinghua University, Beijing 100084, China; State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China.
| | - Dayi Zhang
- School of Environment, Tsinghua University, Beijing 100084, China; State Key Joint Laboratory of Environment Simulation and Pollution Control, Tsinghua University, Beijing 100084, China; Research Institute for Environmental Innovation (Suzhou), Tsinghua, Suzhou 215163, China.
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14
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Sun Z, Kang IS, Wu Q, Xi J, Hu H. Biotoxicity of Water-Soluble UV Photodegradation Products for 10 Typical Gaseous VOCs. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2018; 15:ijerph15071520. [PMID: 30021988 PMCID: PMC6069044 DOI: 10.3390/ijerph15071520] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Revised: 07/11/2018] [Accepted: 07/16/2018] [Indexed: 11/16/2022]
Abstract
Ultraviolet (UV) photodegradation is increasingly applied to control volatile organic compounds (VOCs) due to its degradation capabilities for recalcitrant compounds. However, sometimes the UV photodegradation products are also toxic and can affect human health. Here, 10 VOCs at 150~200 ppm in air were treated using a laboratory-scale UV reactor with 185/254 nm irradiation, and the biotoxicity of their off-gas was studied by investigating their off-gas absorption solutions. The CO2 increase and VOC decrease were 39~128 ppm and 0~42 ppm, respectively, indicating that the VOCs and their products were mineralized in off-gas absorption solutions. The total organic carbon (TOC) of the absorption solutions are 4~20 mg∙L−1. Luminescent bacteria and Daphnia magna were used to detect the acute toxicity, and an umu assay was used to determine the genotoxic potential. Trichloroethylene showed a highest toxicity to luminescent bacteria, while chlorobenzene had the lowest toxicity. Water-soluble UV photodegradation products for styrene are very toxic to Daphnia magna. In the umu assay, the genotoxicities of off-gas absorption solutions of trichloroethylene, methylbenzene, ethyl acetate, butyl alcohol, and styrene were 51.26, 77.80, 86.89, 97.20, and 273.62 mg (4-NQO)·L−1 respectively. In addition, the analysis of the genotoxicity/TOC and intermediates products indicated that the off-gas absorption solutions of styrene, trichloroethylene, and butyl alcohol contain many highly toxic substances.
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Affiliation(s)
- Zhuqiu Sun
- Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing 100084, China.
| | - In-Sun Kang
- Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing 100084, China.
| | - Qianyuan Wu
- State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China.
| | - Jinying Xi
- Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing 100084, China.
- State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China.
| | - Hongying Hu
- Environmental Simulation and Pollution Control State Key Joint Laboratory, School of Environment, Tsinghua University, Beijing 100084, China.
- State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC), Graduate School at Shenzhen, Tsinghua University, Shenzhen 518055, China.
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