Preparation of ionic liquids microemulsion and its application for the treatment of oily sludge

Abstract

The surface-active ILs [C₁₆mim]Cl synthesized by combining imidazole group (C₄H₆N₂) and 1-chlorohexadecane (C₁₆H₃₃Cl) was used as surfactant to prepare ILs microemulsions for sludge treatment. Meanwhile, the treatment conditions were optimized and the optimal conditions were obtained. Due to the strong interaction between ILs and asphaltenes as well as the solubilization of microemulsions, the residual oil rate of oily sludge decreased to 1.33%. The characterization of oily sludge was performed by scanning electron microscope (SEM), fourier transform infrared spectroscopy (FTIR) and contact angle measurement. Results showed that [C₁₆mim]Cl ILs microemulsions treatment could effectively promoted the desorption of asphaltenes from the surface of sludge solids, which provided a clear understanding of the mechanism for ILs microemulsions-enhanced oily sludge recovery.

Graphical Abstract

Oil in Water (O/W) microemulsions prepared using ionic liquids [C₁₆mim]Cl as surfactants were used to the treatment of oily sludge with high removal oil rate (97.97%) and low residual oil rate (1.33%). Based on the strong interaction between [C₁₆mim]Cl and asphaltenes as well as the solubilization effect of microemulsions, the use of ionic liquids microemulsions improves the effect of sludge treatment and realizes the effective recovery of crude oil, which has potential applications in the field of energy recovery and environmental protection.

Keywords:

• Oily sludge
• microemulsions
• ionic liquids
• solubilization

Acknowledgements

We are thankful for the financial support from National Natural Science Foundation Young Investigator Grant Program, China (Project no. 21706148), Natural Science Foundation of Shandong Province, China (Project nos. ZR2019MEM010, ZR2020MD108, ZR2021MB139), and Hubei Jingmen Science and Technology Planning Project (Project No. 2021YFZD030).

Disclosure statement

No potential competing interest was reported by the authors.

Additional information

Funding

This work was funded by National Natural Science Foundation of China; National Natural Science Foundation of China-Shandong Joint Fund; Hubei Jingmen Science and Technology Planning Project.