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

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.

Effects of various durations of enzyme hydrolysis on properties of starch-based wood adhesive.

Improving the performance of wood adhesive is important for the development of the veneer industry. This work investigated the effects of various durations of enzymatic hydrolysis to improve and enhance the properties of starch-based wood adhesive (SWA). The results showed that moderate enzymatic hydrolysis for 2 h of starch molecule could improve the properties of SWA. The bonding strength of SWA was increased from 2.72 MPa (0 h) to 6.87 MPa (2 h) in the dry state and from 0.87 MPa (0 h) to 2.69 MPa (2 h) in the wet state. A significant decrease in the viscosity of SWA was also observed after 2 h hydrolysis of starch molecules, which allowed smooth spreading and penetration of adhesive through the wood surface. Meanwhile, the dynamic mechanical analysis and scanning electron microscopy showed that SWA with 2 h enzymatic hydrolysis exhibited better elastic deformation and smooth surfaces compared with SWA with un-hydrolysis starch. This study provides important information regarding the possible applications of SWA in the wood industry and presents a potential alternative to less environmentally friendly formaldehyde-based wood adhesives.