Photoinduced Superwetting Single-Walled Carbon Nanotube/TiO₂ Ultrathin Network Films for Ultrafast Separation of Oil-in-Water Emulsions

Abstract

A SWCNT/TiO2 nanocomposite ultrathin film that has superhydrophilic and underwater superoleophobic properties after UV-light irradiation is successfully prepared by coating TiO2 via the sol-gel process onto an SWCNT ultrathin network film. The robust and flexible SWCNT/TiO2 nanocomposite films with a thickness and pore size of tens of nanometers can separate both surfactant-free and surfactant-stabilized oil-in-water emulsions in an ultrafast manner with fluxes up to 30 000 L m(-2) h(-1) bar(-1), which is 2 orders of magnitude higher than commercial filtration membranes with similar separation performance, and with high separation efficiency. Most importantly, the films exhibit excellent antifouling and self-cleaning performance during multiple cycles with the aid of the photocatalytic property of TiO2 nanoparticles. This work provides a route for designing ultrathin and superwetting films for effective separation of oil-in-water emulsions. The SWCNT/TiO2 ultrathin film is potentially useful in treating emulsified wastewater produced in industry and daily life and for purification of crude oil and fuel.

Recent Progress in Self-Cleaning Materials with Different Suitable Applications

“…The specific characteristics of this kind of materials have various applications in different areas that can be such as controlled drug delivery, membranes and sensors and finally surface coatings (Xie et al, 2014;Xu et al, 2013c;Mills et al, 2012;Yang et al, 2002;Sawai et al, 2013). In this regard-, there are some factors with higher importance in case of leading the nature of wetting which includes degree of the surface polarity, morphology and roughness of the surface (Wang and Guo, 2014;Gao et al, 2014a). One researcher called Li, together with his colleagues, worked on providing a new micro-Nano silica/titanium thin-film combination through Nano-spheres of TiO 2 and SiO 2 and a kind of water-resistant substances i.e., Aquapel.…”

Oil‐Water Separation: A Gift from the Desert

“…Sand also contains Oil-water separation is the subject of theoretical and practical research around the world because of the frequency with which oil spills occur and the increasing amounts of oily industrial wastewater that are produced. [1][2][3][4][5][6][7] For example, the Gulf of Mexico oil spill in 2010 resulted in 780 × 10 6 L of oil being released into the sea. [ 8 ] This accident caused huge economic losses and had serious effects on the environment.…”

Carbon Nanomaterials Based Membranes

“…Membrane shows excellent performance for separating oil-in-water with high separation efficiency. Further, membrane shows excellent antifouling and selfcleaning performance due to the photo-catalytic degradation of organic compounds by the TiO 2 nanoparticles [20]. Hydrophobic polymer/CNT hybrid membrane can be fabricated via grafting of hydrophobic polymers on the surface of CNT membrane which can separate wide range of organic solvent from the water with excellent adsorption capacity and good recyclability of membranes [21].…”