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Li W, Zeng H, Tang T. Molecular dynamics simulation on water/oil interface with model asphaltene subjected to electric field. J Colloid Interface Sci 2022; 628:924-934. [PMID: 35963177 DOI: 10.1016/j.jcis.2022.08.027] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Revised: 07/24/2022] [Accepted: 08/04/2022] [Indexed: 11/15/2022]
Abstract
HYPOTHESIS The droplet-medium interfaces of petroleum emulsions are often stabilized by the indigenous surface-active compounds (e.g., asphaltenes), causing undesired issues. While demulsification by electric field is a promising technique, fundamental study on the droplet-medium interface influenced by electric field is limited. Molecular dynamics (MD) simulations are expected to provide microscopic insights into the nano-scaled water/oil interface. METHODS MD simulations are conducted to study the adsorption of model asphaltene molecules (represented by N-(1-hexylheptyl)-N'-(5-carboxylicpentyl) perylene-3,4,9,10-tetracarboxylic bisimide (C5Pe)) on a water-toluene interface under various strengths of electric field. The adsorption amount and structural feature of C5Pe molecules at water-toluene interface are investigated, and the effects of electric field and salt are discussed. FINDINGS C5Pe molecules tend to adsorb on the water-oil interface. As the electric field strength increases, the adsorption amount first slightly increases (or remains constant) and then decreases. The electric field disrupts the compact π-π stacking between C5Pe molecules and increases their mobility, causing a dispersed distribution of the molecules with a wide range of orientations relative to the interface. Within the studied range, the addition of salt ions appears to stabilize the interface at high electric field. These results provide useful insights into the mechanism and feasibility of demulsification under electric field.
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Affiliation(s)
- Wenhui Li
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada
| | - Hongbo Zeng
- Department of Chemical and Materials Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada.
| | - Tian Tang
- Department of Mechanical Engineering, University of Alberta, Edmonton, AB T6G 1H9, Canada.
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Earnden L, Marangoni AG, Gregori S, Paschos A, Pensini E. Zein-Bonded Graphene and Biosurfactants Enable the Electrokinetic Clean-Up of Hydrocarbons. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:11153-11169. [PMID: 34514802 DOI: 10.1021/acs.langmuir.1c02018] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Nonaqueous phase liquids (NAPL, e.g., hydrocarbons and chlorinated compounds) are common groundwater pollutants. Electrokinetic remediation of NAPLs uses electric fields to draw them toward electrodes and remove them from groundwater. The treatment requires NAPL mobility. Emulsification increases mobility, but at a risk for downstream receptors. We propose using alkaline aqueous solutions of zein and graphene nanoparticles (GNP) to form conductive materials, which could also act as barriers to control NAPL migration. Alkaline zein-GNP solutions can be injected in the polluted soil and solidified by neutralizing the pH (e.g., with glacial acetic acid, GAA). Shear rheology experiments showed that zein-GNP composites were cohesive, and voltammetry showed that GNP increased electrical conductivity of zein-based materials by 3.5 times. Gas chromatography-mass spectroscopy (GC-MS) demonstrated that the electrokinetic treatment of model sandy aquifers yielded >60% and ∼47% removal of emulsified toluene in freshwater and in salt solutions, respectively (with 30 min treatment using a 10 V differential voltage between a zein-GNP and an aluminum electrode. NaCl was used as model salt contaminant. The conductivity of surfactant solutions was lower in saline water than in freshwater, explaining differences in toluene removal. Toluene-water emulsions were stabilized using the natural surfactants lecithin and saponin. These surfactants acted synergistically in stabilizing emulsions in either freshwater or salt solutions. Lecithin and saponin likely interacted at toluene-water interfaces, as indicated by the morphology, interfacial tension and compressional rigidity of toluene-water interfaces with both components (relative to interfaces of either lecithin or saponin alone). The compressional behavior of interfacial films was well-described by the Marczak model. Electrokinetic treatment of saturated model sandy aquifers also decreased the turbidity of emulsions of water and either tricholoroethylene (TCE, by ∼41%) or diesel (by ∼75%), in the presence of a bacterial biosurfactant. This decrease was used as semiquantitative indicator of NAPL removal from water.
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Affiliation(s)
- Laura Earnden
- University of Guelph, School of Engineering, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada
| | - Alejandro G Marangoni
- University of Guelph, Food Science Department, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada
| | - Stefano Gregori
- University of Guelph, School of Engineering, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada
| | - Athanasios Paschos
- McMaster University, Department of Biology, 1280 Main Street West, Hamilton, Ontario L8S 4K1, Canada
- Mohawk College, School of Engineering and Technology, 135 Fennell Ave W, Hamilton, Ontario L9C 0E5, Canada
| | - Erica Pensini
- University of Guelph, School of Engineering, 50 Stone Road East, Guelph, Ontario N1G 2W1, Canada
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Thin liquid films: Where hydrodynamics, capillarity, surface stresses and intermolecular forces meet. Curr Opin Colloid Interface Sci 2021. [DOI: 10.1016/j.cocis.2021.101441] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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Injectable cationic traps and sticky bacterial emulsifiers: A safe alliance during diesel bioremediation. Colloids Surf A Physicochem Eng Asp 2021. [DOI: 10.1016/j.colsurfa.2020.126051] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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Laccase-zein interactions at the air-water interface: Reactors on an air bubble and naphthalene removal from water. Colloids Surf A Physicochem Eng Asp 2020. [DOI: 10.1016/j.colsurfa.2020.125518] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Yang Z, Zu Y, Zhu J, Jin M, Cui T, Long X. Application of biosurfactant surfactin as a pH-switchable biodemulsifier for efficient oil recovery from waste crude oil. CHEMOSPHERE 2020; 240:124946. [PMID: 31726598 DOI: 10.1016/j.chemosphere.2019.124946] [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: 11/14/2018] [Revised: 09/19/2019] [Accepted: 09/22/2019] [Indexed: 05/12/2023]
Abstract
Efficient oil separation is the most desirable, but still challenging solution for the waste crude oil problem. This study developed biosurfactant surfactin as a novel pH-switchable biodemulsifier for efficient oil separation. As found, surfactin demulsification achieved a quite well oil separation ratio of over 95% on model emulsions after 20 min at 50 °C. The validity of this demulsification process should be mainly based on the readily lost stabilization ability of surfactin in emulsions triggered by acid addition. Then, surfactin (0.2 g/L) treatment with the aid of ethanol (2%) to improve its distribution could recover over 95% of oil from waste crude oil. After treated by surfactin, the separated oil phase contains tiny water (less than 0.5%) and thus can be reused for resource recycling to reach a compromised balance between satisfying the strict environmental regulations and decreasing the high treatment costs. Hence, in consideration of high demulsification efficiency, environmental-friendly properties and cost-efficiency, surfactin has a great potential for industrial applications for oil recovery from waste crude oil which is a severe problem presents in most of the petroleum-related factories.
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Affiliation(s)
- Ziyun Yang
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, PR China
| | - Yunqiao Zu
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, PR China
| | - Jinshan Zhu
- Zhejiang Qianjiang Biochemical Co. Ltd, Haining, Zhejiang, 314400, PR China
| | - Mingjie Jin
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, PR China.
| | - Tianyou Cui
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, PR China
| | - Xuwei Long
- School of Environmental and Biological Engineering, Nanjing University of Science and Technology, Nanjing, 210094, PR China.
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Chang CC, Williams I, Nowbahar A, Mansard V, Mecca J, Whitaker KA, Schmitt AK, Tucker CJ, Kalantar TH, Kuo TC, Squires TM. Effect of Ethylcellulose on the Rheology and Mechanical Heterogeneity of Asphaltene Films at the Oil-Water Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:9374-9381. [PMID: 31256591 DOI: 10.1021/acs.langmuir.9b00834] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Asphaltenes are surface-active molecules that exist naturally in crude oil. They adsorb at the water-oil interface and form viscoelastic interfacial films that stabilize emulsion droplets, making water-oil separation extremely challenging. There is, thus, a need for chemical demulsifiers to disrupt the interfacial asphaltene films, and, thereby, facilitate water-oil separation. Here, we examine ethylcellulose (EC) as a model demulsifier and measure its impact on the interfacial properties of asphaltene films using interfacial shear microrheology. When EC is mixed with an oil and asphaltene solution, it retards the interfacial stiffening that occurs between the oil phase in contact with a water phase. Moreover, EC introduces relatively weak regions within the film. When EC is introduced to a pre-existing asphaltene film, the stiffness of the films decreases abruptly and significantly. Direct visualization of interfacial dynamics further reveals that EC acts inhomogeneously, and that relatively soft regions in the initial film are seen to expand. This mechanism likely impacts emulsion destabilization and provides new insight to the process of demulsification.
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Affiliation(s)
- Chih-Cheng Chang
- Department of Chemical Engineering , University of California , Santa Barbara , California 93106-5080 , United States
| | - Ian Williams
- Department of Chemical Engineering , University of California , Santa Barbara , California 93106-5080 , United States
- Department of Chemistry , University College London , 20 Gordon Street , London WC1H 0AJ , U.K
| | - Arash Nowbahar
- Department of Chemical Engineering , University of California , Santa Barbara , California 93106-5080 , United States
| | - Vincent Mansard
- Department of Chemical Engineering , University of California , Santa Barbara , California 93106-5080 , United States
- Laboratory for Analysis and Architecture of Systems , Toulouse 31400 , France
| | - Jodi Mecca
- The Dow Chemical Company , Midland , Michigan 48674 , United States
| | | | - Adam K Schmitt
- The Dow Chemical Company , Midland , Michigan 48674 , United States
| | | | - Tom H Kalantar
- The Dow Chemical Company , Midland , Michigan 48674 , United States
| | - Tzu-Chi Kuo
- The Dow Chemical Company , Midland , Michigan 48674 , United States
| | - Todd M Squires
- Department of Chemical Engineering , University of California , Santa Barbara , California 93106-5080 , United States
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Huang B, Li X, Zhang W, Fu C, Wang Y, Fu S. Study on Demulsification-Flocculation Mechanism of Oil-Water Emulsion in Produced Water from Alkali/Surfactant/Polymer Flooding. Polymers (Basel) 2019; 11:polym11030395. [PMID: 30960379 PMCID: PMC6473720 DOI: 10.3390/polym11030395] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 02/14/2019] [Accepted: 02/22/2019] [Indexed: 12/02/2022] Open
Abstract
The issue of pipeline scaling and oil-water separation caused by treating produced water in Alkali/Surfactant/Polymer (ASP) flooding greatly limits the wide use of ASP flooding technology. Therefore, this study of the demulsification-flocculation mechanism of oil-water emulsion in ASP flooding produced water is of great importance for ASP produced water treatment and its application. In this paper, the demulsification-flocculation mechanism of produced water is studied by simulating the changes in oil-water interfacial tension, Zeta potential and the size of oil droplets of produced water with an added demulsifier or flocculent by laboratory experiments. The results show that the demulsifier molecules can be adsorbed onto the oil droplets and replace the surfactant absorbed on the surface of oil droplets, reducing interfacial tension and weakening interfacial film strength, resulting in decreased stability of the oil droplets. The demulsifier can also neutralize the negative charge on the surface of oil droplets and reduce the electrostatic repulsion between them which will be beneficial for the accumulation of oil droplets. The flocculent after demulsification of oil droplets by charge neutralization, adsorption bridging, and sweeping all functions together. Thus, the oil droplets form aggregates and the synthetic action by the demulsifier and the flocculent causes the oil drop film to break up and oil droplet coalescence occurs to separate oil water.
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Affiliation(s)
- Bin Huang
- The Key Laboratory of Enhanced Oil and Gas Recovery of Educational Ministry, Northeast Petroleum University, Daqing 163318, China.
| | - Xiaohui Li
- The Key Laboratory of Enhanced Oil and Gas Recovery of Educational Ministry, Northeast Petroleum University, Daqing 163318, China.
| | - Wei Zhang
- Shandong Key Laboratory of Oil-Gas Storage and Transportation Safety, College of Pipeline and Civil Engineering, China University of Petroleum, Qingdao 266580, China.
| | - Cheng Fu
- The Key Laboratory of Enhanced Oil and Gas Recovery of Educational Ministry, Northeast Petroleum University, Daqing 163318, China.
- Post-Doctoral Research Station of Daqing Oilfield, Daqing 163458, China.
| | | | - Siqiang Fu
- No. 1 Oil Production Plant in Daqing Oilfield, Daqing 163001, China.
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Wang Z, Lin X, Yu T, Zhou N, Zhong H, Zhu J. Formation and rupture mechanisms of visco-elastic interfacial films in polymer-stabilized emulsions. J DISPER SCI TECHNOL 2018. [DOI: 10.1080/01932691.2018.1478303] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- Zhihua Wang
- Key Laboratory for Enhanced Oil & Gas Recovery of the Ministry of Education, Northeast Petroleum University, Daqing, China
| | - Xinyu Lin
- Key Laboratory for Enhanced Oil & Gas Recovery of the Ministry of Education, Northeast Petroleum University, Daqing, China
| | - Tianyu Yu
- School of Mechanical and Chemical Engineering, University of Western Australia, Western Australia, Australia
| | - Nan Zhou
- Key Laboratory for Enhanced Oil & Gas Recovery of the Ministry of Education, Northeast Petroleum University, Daqing, China
| | - Huiying Zhong
- Key Laboratory for Enhanced Oil & Gas Recovery of the Ministry of Education, Northeast Petroleum University, Daqing, China
| | - Jianjun Zhu
- McDougall School of Petroleum Engineering, The University of Tulsa, Tulsa, USA
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