Salt-Induced Constructions of Gemini-like Surfactants at the Interface and Their Effects on the Interfacial Tension of a Water/Model Oil System |
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Authors: | Han Jia Pan Huang Hongyan Wu An Ma Hongtao Zhou |
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Affiliation: | School of Petroleum Engineering, China University of Petroleum (East China), Qingdao 266580, China |
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Abstract: | It is an urgent issue to enhance oil recovery for unconventional reservoirs with high salinity. Focused on this topic, salt addition is a powerful tool to motivate the surfactant assembly at the water/oil interface and improve the interfacial activity. We used a cationic surfactant cetyltrimethylammonium bromide (CTAB) and an anionic salt dicarboxylic acid sodium (CnDNa) to construct gemini-like surfactants at the interface and evaluated their ability to reduce the interfacial tension (IFT) between model oil (toluene and n-decane, v:v = 1:1) and water. Interestingly, the fabrication of a (CTAB)2/C4DNa gemini-like surfactant was hardly achieved at the fresh water/model oil interface, but accomplished at the brine/model oil interface. At a high NaCl concentration (100,000 mg L−1), the IFT value is reduced to 10−3 mN m−1 order of magnitude, which is generally desired in practical applications. The control experiments displacing the surfactant type and the spacer length further confirmed the NaCl effects on the interfacial assembly. |
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Keywords: | Cationic surfactant Gemini surfactants Interfacial science Applications of surfactants |
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