scholarly journals Delamination-Free In-Air and Underwater Oil-Repellent Filters for Oil-Water Separation: Gravity-Driven and Cross-Flow Operations

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7429
Author(s):  
Bishwash Shrestha ◽  
Mohammadamin Ezazi ◽  
Gibum Kwon

Separating oil-water mixtures is critical in a variety of practical applications, including the treatment of industrial wastewater, oil spill cleanups, as well as the purification of petroleum products. Among various methodologies that have been utilized, membranes are the most attractive technology for separating oil-water emulsions. In recent years, selective wettability membranes have attracted particular attention for oil-water separations. The membrane surfaces with hydrophilic and in-air oleophobic wettability have demonstrated enhanced effectiveness for oil-water separations in comparison with underwater oleophobic membranes. However, developing a hydrophilic and in-air oleophobic surface for a membrane is not a trivial task. The coating delamination process is a critical challenge when applying these membranes for separations. Inspired by the above, in this study we utilize poly(ethylene glycol)diacrylate (PEGDA) and 1H,1H,2H,2H-heptadecafluorodecyl acrylate (F-acrylate) to fabricate a hydrophilic and in-air oleophobic coating on a filter. We utilize methacryloxypropyl trimethoxysilane (MEMO) as an adhesion promoter to enhance the adhesion of the coating to the filter. The filter demonstrates robust oil repellency preventing oil adhesion and oil fouling. Utilizing the filter, gravity-driven and continuous separations of surfactant-stabilized oil-water emulsions are demonstrated. Finally, we demonstrate that the filter can be reused multiple times upon rinsing for further oil-water separations.

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 457
Author(s):  
Chunlei Ren ◽  
Wufeng Chen ◽  
Chusheng Chen ◽  
Louis Winnubst ◽  
Lifeng Yan

Porous Al2O3 membranes were prepared through a phase-inversion tape casting/sintering method. The alumina membranes were embedded with finger-like pores perpendicular to the membrane surface. Bare alumina membranes are naturally hydrophilic and underwater oleophobic, while fluoroalkylsilane (FAS)-grafted membranes are hydrophobic and oleophilic. The coupling of FAS molecules on alumina surfaces was confirmed by Thermogravimetric Analysis and X-ray Photoelectron Spectroscopy measurements. The hydrophobic membranes exhibited desired thermal stability and were super durable when exposed to air. Both membranes can be used for gravity-driven oil/water separation, which is highly cost-effective. The as-calculated separation efficiency (R) was above 99% for the FAS-grafted alumina membrane. Due to the excellent oil/water separation performance and good chemical stability, the porous ceramic membranes display potential for practical applications.


2021 ◽  
Author(s):  
Cailin Liu ◽  
Li Yu ◽  
Yue Fan ◽  
Chang Li ◽  
Xianyan Ren ◽  
...  

Abstract In the oil-water separation, the difficulty to recover and low hydrophobicity are key limitation factors for practical applications. In this paper, we design Cobalt ferrite hybird Polystyrene divinylbenzene microspheres (CoFe2O4/SDB), which were conducted through in-situ suspension copolymerization. The CoFe2O4 is prepared by low heat solid phase sol-gel method. It had been found that the CoFe2O4/SDB have a spherical structure, good adsorption behavior, highly hydrophobicity and even superhydrophobicity. The adsorption capacity of CoFe2O4/SDB composites could absorb kerosene up to 6 times of its own weight. Interestingly, kerosene can be easily separated from the surface of CoFe2O4/SDB particles with ultrasonic operation. CoFe2O4/SDB particles can still maintain good hydrophobicity and adsorption capacity of kerosene after 11 cycles after drying. With in situ polymerization of St、DVB and CoFe2O4, CoFe2O4/SDB as a promising absorbent of kerosene which has great potential in application of oil-water separation.


2018 ◽  
Vol 338 ◽  
pp. 271-277 ◽  
Author(s):  
Chenghong Ao ◽  
Rui Hu ◽  
Jiangqi Zhao ◽  
Xiaofang Zhang ◽  
Qingye Li ◽  
...  

Nanoscale ◽  
2016 ◽  
Vol 8 (14) ◽  
pp. 7638-7645 ◽  
Author(s):  
Jian Li ◽  
Ruimei Kang ◽  
Xiaohua Tang ◽  
Houde She ◽  
Yaoxia Yang ◽  
...  

Author(s):  
Balraj K. Tudu ◽  
Aditya Kumar ◽  
Bharat Bhushan

Superoleophobicity is of interest for practical applications such as liquid repellency, self-cleaning, stain resistance, anti-bacterial properties and oil–water separation. In this work, the superoleophobic coating on cotton fabric was applied by simple immersion in TiO 2 nanoparticles, perfluorodecyltriethoxysilane and tertraethylorthosilicate solution. Its anti-wetting properties, surface morphology and functionality were characterized. The coated cotton fabric shows superoleophobicity with oil (surface tension more than 27 mN m −1 ) contact angle of 152° and tilt angle of 6°. Furthermore, the superoleophobic cotton fabric was demonstrated to exhibit self-cleaning, stain resistance, mechanical durability, chemical stability, thermal stability, anti-bacterial properties and oil–water separation capabilities. This article is part of the theme issue ‘Bioinspired materials and surfaces for green science and technology (part 2)’.


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