Design, Development, and Outlook of Superwettability Membranes in Oil/Water Emulsions Separation

Abstract

Oil leakage and discharge of industrial organic solvents are the main reasons for the oily wastewater. The separation of oil/water emulsions has been a global challenge due to the small particle size of the emulsions and their stabilities. An effective method is needed to resolve these issues. Superwettability membrane method has demonstrated a high separation efficiency, fast separation speed, low energy consumption, good scalability, easy operation, and recyclability. In essence, the special wettability of material is mainly determined by two factors: the chemical compositions of material surface and the surface morphology. Herein, in this review, the development of special wettability separation membranes is discussed including different preparation methods, and material preparation, such as superhydrophobic/super lipophilic, superhydrophilic/underwater superoleophobic, superlipophilic/superhydrophobic under oil, smart membranes with switchable wettability, and special wettability membranes with self‐healing or self‐cleaning property. The representative works of each part are introduced, focusing on preparation methods, innovations and separation performance of membranes. Finally, challenges and future directions in this field are also described.

Recent Progress in Microfiltration/Ultrafiltration Membranes for Separation of Oil and Water Emulsions

“…For instance, the epidermal wax layer can selfrepair and retain its superhydrophobicity after the damage is one of the examples of materials that can be useful to prepare the self-repairing membranes. [254] Self-repairing superhydrophobic coatings have the potential to address durability issues effectively. On this principle, the self-repairing superhydrophobic surface consists of poly (allylamine hydrochloride) and sulfonated poly (ethylenketone) coatings with poly (acrylic acid) (PAA).…”

Textured ceramic membranes for desilting and deoiling of produced water in the Permian Basin

“…Membrane-based technologies can potentially provide a viable alternative for PW management at a relatively lower cost and higher throughput. These technologies hold promise for improved water quality, compact design, facile operation, and low energy consumption ( Cai et al., 2021 ; Babayev et al., 2019 ). An effective membrane module can greatly enhance the efficiency of PW treatment trains.…”

Swelling poly(ionic liquid)s for demulsifying oil‐in‐water emulsion by anion exchange

“…Currently, the excessive discharge of stable oil/water emulsions poses tremendous threats to human health and ecological equilibrium, especially contaminated oil/water emulsions from domestic and industrial processes. [1][2][3] The common demulsification methods include various physical (e.g., gravitational settling, thermal treatment, 4 membrane separation, 5 electricity, 6 ultrasonic 7 ), biological (bioaugmentation, 8 biostimulation 9 ), and chemical (e.g., solidifiers, 10 demulsifiers, adsorption 11 ) processes. Among these mentioned technologies, chemical demulsification is an effective method, which has been widely used in industries for breaking emulsions.…”