Muthanna Journal of Engineering and Technology
Volume (14), Issue (3), Year (2026), Pages (16-37)
DOI:10.52113/3/eng/mjet/2026-14-03-/16-37
Research Article By:
Karrar N.Adhap, Salih A. Rushdi, H.I. Dawood, Sanaa Mateab
Corresponding author E-mail: Karrar.nasser.adhap@qu.edu.iq
ABSTRACT
The presence of highly stable water in oil (w/o) , oil in water (o/w) and oil in water in oil (o/w/o)emulsions have been a major problem to oil production and treatment of oily wastewater, especially, in the presence of sub-micron droplets that are stabilized by asphaltenes, resins and fine solids. Droplets that are less than 10 micrometers cannot be easily separated by any conventional gravity-based method, which means that their efficiency is low and they cost a lot to operate. The present review offers a mechanistic comparison and contrast of the traditional and emerging methodologies of emulsion separation, such as chemical, electrostatic, membrane-based, ultra-sonic and nanomaterial-based methods. The study lays emphasis on recent advances between 2022 and 2025 including ionic liquid-based emulsion separators, biomaterials, and hybrid separation systems. The analysis demonstrates that the effective interface is unstable, which facilitates droplet amalgamation whereby the sub-micron droplets are able to increase to larger droplets (more than 50 micrometers), thereby increasing the efficiency of separation to a considerable extent. In the published literature, oil-water sepa-ration efficiencies of more than 90% are possible under ideal circumstances. In most cases, the performance of separation is mostly influenced by surface characteristics and not by operating intensity. This review gives an overview of the existing weaknesses and emphasizes the potential of semiconductor and hybrid systems in designing efficient and sustainable crude oil emulsion separation technologies.
Keywords: Demulsification, Water-in-oil (W/O) emulsions, Nanofluids, Coalescence kinetics, Interfacial chemistry.