γ-Cyclodextrin-based metal-organic frameworks for lactonic sophorolipid application in enhanced oil recovery

• Published in: Carbohydrate polymers Vol. 314; p. 120931
• Main Authors: Zhang, Tingting, He, Hao, Xu, Qing, Lv, Jiasheng, Wu, Chaoyi, Zhou, Yefei, Wang, Zhenjiong
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.08.2023
• Subjects: Cyclodextrin; Emulsification index; Enhanced oil recovery; Lactonic sophorolipid; Metal-organic framework; Viscosity-reducing efficiency; Cyclodextrin; Enhanced oil recovery; Emulsification index; Viscosity-reducing efficiency; Metal-organic framework; Lactonic sophorolipid; γ-Cyclodextrin (PubChem CID 5287407); Lactonic sophorolipid (PubChem CID 117065237)
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2023.120931

Lactonic sophorolipid (LSL) exhibits numerous surfactant activities, such as emulsification, wetting action, dispersion effect, and oil-washing activities. Nevertheless, LSLs have poor water solubility, which restrains their application in the petroleum industry. In this research, a new compound, lactonic sophorolipid cyclodextrin metal-organic framework (LSL-CD-MOFs), was obtained by loading LSL into γ-cyclodextrin metal-organic frameworks (γ-CD-MOFs). The LSL-CD-MOFs were characterized by N2 adsorption analysis, X-ray powder diffraction analysis, Fourier transform infrared spectroscopy, and thermogravimetric analysis. Loading LSL into γ-CD-MOFs significantly increased the apparent water solubility of LSL. However, the critical micelle concentration of LSL-CD-MOFs was similar to that of LSL. Furthermore, LSL-CD-MOFs effectively reduced the viscosities and improved the emulsification indices of oil–water mixtures. Oil-washing tests, which were conducted using oil sands, revealed that the LSL-CD-MOFs yielded an oil-washing efficiency of 85.82 % ± 2.04 %. Overall, γ-CD-MOFs are promising carriers for LSL, and LSL-CD-MOFs are a potential, low-cost, new, green surfactant for enhanced oil recovery. (A) Synthesis of γ-CD-MOFs. (B) Synthesis of LSL-CD-MOFs. (C) Lactonic sophorolipid (LSL) in water solution. (D) Emulsifying process. (E) Interfacial tension. (F) Oil-washing process. [Display omitted] •γ-CD-MOFs were developed as a novel carriercarriers for the lactonic sophorolipid (LSL) delivery system.•The water solubility of LSL significantly improved after embedding.•The oil-washing efficiency of LSL-CD-MOFs increased by 4.2 times.