Strategies for the construction of special wettability metal organic framework membranes: A review

Abstract

Much oily wastewater containing emulsions are generated daily in various industrial processes such as petroleum and gas extraction, petrochemical, and mechanical processing. If the oily wastewater is directly discharged, it will issue a vast waste of water resources and increase environmental risks around the plant. The efficient treatment and reuse of oily wastewater will achieve a win-win situation of environmental protection and economy in the production of enterprises. The pressure-driven membrane separation technology can easily and quickly realize the separation of oil and water under the condition of low energy consumption. It stands out from all kinds of high energy consumption and complex technologies. Super-wettable membranes are brilliant in treating oily wastewater, especially separating emulsions with small particle sizes. Metal-organic frameworks (MOFs) are nanomaterials that can be tailored on demand, and their tunable surface structures and chemical compositions exhibit extraordinary potential for super wetting modification. Therefore, this review explains the mechanism of membrane separation of the oil-water mixture from the surface wettability theory and pore sieving theory and then summarizes the preparation methods developed for MOFs membranes in recent years. Based on this, MOF membranes' modification strategies in the oil-water separation field are mainly introduced, and the mainstream modification methods are discussed and evaluated. Finally, it provides ideas for modifying MOF membranes in oil-water separation and puts forward the challenges and difficulties that MOF membranes will face when applied to oil-containing membranes.