Designing novel superwetting surfaces for high-efficiency oil–water separation: design principles, opportunities, trends and challenges

Abstract

Membrane filtration and absorption strategies based on superwetting surface for oil-water separation have regained tremendous attention due to its low cost, high efficiency and environmental friendly advantages. Besides usual superhydrophobic,...

Recent advances in membrane hydrophilic modification with plant polyphenol‐inspired coatings for enhanced oily emulsion separation

“…81 To endow membrane with superhydrophilic/underwater superoleophobic properties, hydrophilic compositions and micro−/nano-scaled structures are both essential according to the Cassie-Baxter model. 64,82 Wang et al developed a one-step, universal and cost-effective way to transform high hydrophobic membranes into superhydrophilic and underwater superoleophobic ones by utilizing the adhesive property of TA along with the interactions between the oxidized TA and hydrolyzed 3-aminopropyltriethoxysilane (APTES), shown in Figure 4(a). 22 As illustrated in Figure 4(b), a hierarchical superhydrophilic coating with distinct layernanosphere structure was firmly formed atop hydrophobic substrates and efficient separation of oil-in-water emulsions was achieved.…”

“…Superhydrophilic surface of membrane plays a significant role in elevating permeate flux, rejecting oils as well as resisting oil fouling 81 . To endow membrane with superhydrophilic/underwater superoleophobic properties, hydrophilic compositions and micro−/nano‐scaled structures are both essential according to the Cassie‐Baxter model 64,82 . Wang et al developed a one‐step, universal and cost‐effective way to transform high hydrophobic membranes into superhydrophilic and underwater superoleophobic ones by utilizing the adhesive property of TA along with the interactions between the oxidized TA and hydrolyzed 3‐aminopropyltriethoxysilane (APTES), shown in Figure 4(a) 22 .…”

“…There have been several enlightening reviews published recently covering theory basis related to surface wetting behavior, separation mechanisms and design principles of surfaces with special wettability for oil/ water separation, smart polymeric materials for controllable oil/water separation, bio-inspired super-wettability, and so on. [63][64][65][66] However, limited attention has been paid on recent developments in membrane hydrophilic modification with the emerging plant polyphenol-inspired coatings for enhanced oily emulsion separation. Of note, the formation of the coatings is facile and green, which only requires polyphenol precursor, aqueous buffer solution and other functional materials.…”

Synchronous oil/water separation and wastewater treatment on a copper-oxide-coated mesh

“…1 Despite various conventional methods including otation, absorbing, ltration and centrifugation for water extraction from oily wastewater, unsatisfactory efficiency, additional energy consumption and complicated operation are always present in the process. [2][3][4][5] To address these drawbacks, functional super-wetting/anti-wetting materials including metals, 6 metal oxides and polymers have been introduced, [7][8][9][10][11][12] achieving high-efficiency and low-cost oil/water separation via their antipodal wettability performance for water and oil. On the one hand, oil-repellent surfaces with superhydrophilic and underwater superoleophobic properties can repel the oil completely while allowing the water phase to pass through, allowing the separation of water and oil.…”

A strategy for preparing controllable, superhydrophobic, strongly sticky surfaces using SiO2@PVDF raspberry core–shell particles

“…2 Typically, superhydrophobic surfaces that exhibit the lotus effect have been used for oil/water separation, reducing friction, increasing thermal stability, increasing transparency, and in vivo drug release, and in self-cleaning, antibacterial, anti-fogging, antiicing, and anti-contamination surfaces. [3][4][5][6][7][8][9][10][11][12][13][14][15] However, in applications like microdrop manipulation, water harvesting, microuidic transportation, chemical/biological separation, microanalysis, and in situ detection, a sticky surface is necessary. [16][17][18][19][20][21][22] This is generally achieved using the rose petal effect, which corresponds to the Wenzel wetting state.…”