Demulsification of water-in-crude oil emulsion using natural lotus leaf treated via a simple hydrothermal process

Looking for efficient, environmentally-friendly, and low-cost demulsifiers for the separation of oil?water emulsion is the goal of oil industry. In current work, natural lotus leaf was used as raw material to prepare a HLLF demulsifier by a simple hydrothermal method without the addition of any chemical reagent. The HLLF demulsifier was utilized to demulsify the water-in-crude oil (W/O) emulsions. Effect of the demulsifier dosage, settling time, temperature and treatment method of HLLF on the demulsification efficiency (DE) was investigated. Encouragingly, the demulsification of the W/O emulsions could occur quickly, and the optimal DE was up to 88.17% with 1000 mg/L of dosage and 90 min of settling time at 70?. Besides, it could effectively demulsify two types of crude oil emulsions from different oilfields. The possible demulsification mechanism was systematically investigated by scanning electron microscope (SEM), three-phase contact angle (CA), dynamic interfacial tensions (IFT), self-assembly of interfacial film and microscopic analysis. The CA value for HLLF was 81.53? and its IFT was 25.65 mN/m with the dosage of 500 mg/L at room temperature. The prominent demulsification ability of HLLF was attributed to the micro-nano structure on its surface, which may soften or destroy the rigid interfacial film to enhance the film drainage. The finding suggests that HLLF is a promising demulsifier for the separation of W/O emulsion, which exhibits a great application prospect in oil industry.

Automated summary

Efficient, environmentally-friendly, and low-cost demulsifiers for the separation of oil?water emulsion are actively sought after in the oil industry. The use of natural lotus leaf to prepare a HLLF demulsifier has successfully achieved a demulsification efficiency of up to 88.17% for water-in-crude oil emulsions. The micro-nano structure of HLLF contributes to its outstanding demulsification ability, showing promising application prospects in the oil industry.