Probing the interactions between asphaltenes and a PEO-PPO demulsifier at oil–water interface: Effect of temperature

• Published in: Journal of colloid and interface science 2025-01, Vol.678 (Pt C), p.1096-1111
• Main Authors: Huang, Yueying, Mao, Xiaohui, Yang, Diling, Qiao, Chenyu, Zhang, Ling, Wang, Jingyi, Zhang, Hao, Zeng, Hongbo
• Format: Article
• Language: English
• Subjects: Asphaltenes-stabilized emulsion; Interfacial behaviors; PEO-PPO copolymer; Surface forces; Temperature effect
• ISSN: 0021-9797; 1095-7103; 1095-7103
• DOI: 10.1016/j.jcis.2024.09.101

[Display omitted] •PEO-PPO type EB exhibits a superior interfacial activity than asphaltenes.•The EB disrupts interfacial asphaltene films to render droplet coalescence.•The EB separates W/O emulsions more efficiently at high temperatures.•High temperature promotes the adsorption kinetics of both EB and asphaltenes.•High temperature facilitates the destruction of asphaltene films by EB molecules. Asphaltenes are primary stabilizers in water-in-oil (W/O) emulsions that cause corrosion and fouling issues. In oil sands industry, oil/water separation processes are generally conducted at high temperatures. A high temperature is expected to impact the interactions between asphaltenes and emulsion breakers (EBs), consequently influencing demulsification performance. The adsorption and interactions of asphaltenes and a PEO-PPO type EB (Pluronic F68) at the oil–water interface were investigated at various temperatures, using tensiometer, quartz crystal microbalance with energy dissipation (QCM-D), and atomic force microscopy (AFM). The effect of temperature on EB’s demulsification performance was explored through bottle tests. Additionally, demulsification mechanisms were studied using direct force measurements with the droplet probe AFM technique. Dynamic interfacial tension and QCM-D results demonstrate that the PEO-PPO type EB exhibits higher interfacial activity than asphaltenes and can disrupt rigid asphaltene films at the oil–water interfaces. Elevated temperatures accelerate the displacement of adsorbed asphaltenes by EB molecules, leading to sparse interfacial films, rapid droplet coalescence, and improved demulsification efficiency (supported by AFM and bottle test results). This work provides valuable insights into interfacial interactions between asphaltenes and EB at different temperatures, enhancing the understanding of demulsification mechanisms and offering useful implications for the development of efficient EBs to enhance oil/water separation performance.