Oil-Water Separation Using a Self-Cleaning Underwater Superoleophobic Micro/Nanowire Hierarchical Nanostructured Membrane

Abstract

In this study, we fabricated a novel micro/nanowire hierarchical membrane with flexible, self-cleaning and underwater superoleophobic properties for efficient oil-water separation under vacuum filtration. This novel membrane composed of ultralong copper microwires (MW) and functional TiO 2 nanowires (NW). The ultralong copper microwires act as a scaffold, as well as providing mechanical flexibility for the membrane, which allow it to be operated under vacuum-driven condition. Meanwhile, underwater superoleophobic TiO 2 nanowires membrane provides nano-scale pore size, ensuring the filtration of smaller oil droplets under vacuum condition. Moreover, the possession of the self-cleaning function of TiO 2 nanowires allows the degradation of foulants and contaminants under UV irradiation, which promote the facile recovery of the used membrane. Clearly, the employment of this novel membrane can be considered as a practical option for efficient oil-water separations.

Recent developments in forward osmosis membranes using carbon-based nanomaterials

“…Contaminants removal from water requires robust and efficient decontamination technologies, which are capable of the treatment of a wide range of impurities. There are various existing physical and chemical technologies for water and wastewater treatment such as gravity separation [6,7], membrane filtration technologies [8][9][10][11][12][13][14], air flotation [15], absorption material includes fluorochemicals, chemical vapor deposition, coating mesh, carbon-based materials, hydrophobic aerogels, sol-gel process, and sponges [16][17][18][19][20][21][22][23][24][25][26]. These technologies can remove a large proportion of dissolved matters [8], but they have some inherent limitations such as low separation or rejection rate, fouling, high energy consumption, reusability, and recyclability of the filtration media [ 9,17,21].…”

Facile Fabrication of a Polyethylene Mesh for Oil/Water Separation in a Complex Environment

“…Oil/water separation is an urgent worldwide challenge, because of the upsurge of water pollution caused by industrial oily wastewater and/or frequent oil spills. − Traditional techniques for oil/water separation have been perfected in the past decades, including gravity separation, − membrane filtration, − air flotation, − adsorption, ,− coagulation, and flocculation . However, new approaches based on special wettability have been considered to be more effective and more advantageous for use, because oil/water separation is essentially an interfacial matter. , Various superwetting interfacial materials fabricated by designing superhydrophobic or superoleophobic surfaces have generated great attention and have been applied for industrial, oily wastewater treatment, including chemical etching, electrospinning, self-assembly processes, and others. ,− Use of the special wettability materials can be generally categorized by the following two strategies: “oil-removing” type materials with superhydrophobicity and superoleophilicity properties that can filter or absorb oils from water and “water-removing” type materials with superhydrophilicity as well as underwater superoleophobicity that can selectively isolate oils from mixtures .…”

Fabrication of bioinspired super-hydrophilic nano-fibrous membrane for oil-water separation and directional water transportation

“…Among those different pollutants, oil pollution has gained worldwide attention, owing to the large scale oil spill accidents, which were regarded as great man-made catastrophes, in recent years (Tai, Tan et al 2015). Moreover, oily wastewater from industries like petroleum, textile, food industry is also regarded as a common source of pollutant (Tan, Liu et al 2016). Therefore, separation of oil from water needs to be studied urgently.…”

“…Metal oxide like titanium dioxide (TiO 2 ) (Tan, Liu et al 2016), silica (SiO 2 ) (Tai, Tan et al 2015), copper oxide (CuO) (Baghbanzadeh, Rana et al 2015), and zinc oxide (ZnO) (Ennaceri, Wang et al 2016) are widely studied due to their especial wetting behaviors. Those metal oxide materials were reported with excellent water affinity and strong underwater stability, so they were regarded as a suitable candidate for oil-water separation , Li, Yan et al 2016, Tian, Li et al 2019.…”

“…Nano-sized metal oxide has gained much attention, because metal oxide alters the surface property and also increases the surface roughness to create micro-/nano-structures (Zan and Wu 2016). Metal oxide like titanium dioxide (TiO 2 ) (Tan, Liu et al 2016), silica (SiO 2 ) (Tai, Tan et al 2015), copper oxide (CuO) (Baghbanzadeh, Rana et al 2015), and zinc oxide (ZnO) (Ennaceri, Wang et al 2016) are widely studied due to their especial wetting behaviors. However, most of these metal oxide modified membranes are based on metal mesh, which has many limitations like large pore size and poor flexibility when applied for oil-water separation (Qin, Liu et al 2016).…”