Recent advances in oil/water separation using nanomaterial-based filtration methods for crude oil processing-a review

The separation of water is essential in crude oil processing. The presence of water-in-crude oil emulsions increases the cost of production and transportation of petroleum oil and causes pump failure, pipeline corrosion, and other problems such as catalysts poisoning in downstream. The present essay aims to provide an overview of the state-of-the-art methods of water and oil separation, particularly practical applications in industry. Salt content causes problems such as corrosion, fouling, or catalyst degradation in the refinery. Water and salt content should be less than 0.1 wt% of the crude oil to control the mentioned problems. For oil and water separation, industrial separation systems such as centrifuges are used but this separation is not complete and the water or oil content is not within the permissible limit. So it is necessary to use a complementary system. Demulsifiers and desalters, which have played a major role in the industry, have problems due to their high dependence on viscosity, high cost, environmental impact, formation of fine secondary droplets, energy consumption, etc. Nanomaterials, especially nanostructures of silicone and carbon, with a better performance have been investigated as a subsequent recommendation rather than demulsifiers in some studies. Presenting environmental stimuli for switch wettability that possess easy applying for industrial operation as well as find a smart material with a similar efficiency to demulsifiers will definitely be able to compete with demulsifiers and other conventional methods and replace with them. Changing surface properties by functionalization of the surface or surface charging followed by hydrophilic-lipophilic balance (HLB) adjustment can enable the surface to do dewatering process or even act as a smart separator with switching from W/O separation to O/W or vice versa. Therefore, this article reviews nanomaterial-based filtration methods as an efficient method for separating water and oil, and studies the advances that researchers have made so far. • An overview of the state-of-the-art methods of water and oil separation. • Drawbacks of conventional and novel oil-water separation systems. • The concerns with demulsifiers in the industry that have the greatest share of use. • Smart nanostructured-based as an alternative to demulsifiers.