Carbon–silica composite nanofiber membrane for high flux separation of water-in-oil emulsion – Performance study and fouling mechanism

Highly efficient removal of emulsified oil from oily wastewater by microfiltration carbon membranes made from phenolic resin/coal

Oily wastewater treatment is a major problem for a large variety of industrial sectors. Membrane filtration is quite promising for oil-in-water emulsion treatment by virtue of numerous eminent advantages. Here, microfiltration carbon membranes (MCMs) were prepared by the blends of phenolic resin (PR)/coal as precursor materials for efficient removal of emulsified oil from oily wastewater. The functional groups, porous structure, microstructure, morphology and hydrophilicity of the MCMs were analysed by Fourier transform infrared spectroscopy, bubble-pressure method, X-ray diffraction, scanning electron microscope and water contact angle, respectively. The effect of coal amount in precursor materials on the structure and properties of MCMs was mainly investigated. Under operation at 0.02 MPa for trans-membrane pressure and 6 mL min-1 for feed flowrate, the optimal oil rejection and water permeation flux are correspondingly attained to 99.1% and 21,388.5 kg m-2 h-1 MPa-1 for MCMs made by the precursor containing 25% coal. Besides, the anti-fouling ability of the as-prepared MCMs is greatly improved in comparison with the one merely made by PR. In summary, the result indicates that the as-prepared MCMs are very promising for oily wastewater treatment.

Membranes for Oil/Water Separation: A Review

Recent advancements in separation and membrane technologies have shown a great potential in removing oil from wastewaters effectively. In addition, the capabilities have improved to fabricate membranes with tunable properties in terms of their wettability, permeability, antifouling, and mechanical properties that govern the treatment of oily wastewaters. Herein, authors have critically reviewed the literature on membrane technology for oil/water separation with a specific focus on: 1) membrane properties and characterization, 2) development of various materials (e.g., organic, inorganic, and hybrid membranes, and innovative materials), 3) membranes design (e.g., mixed matrix nanocomposite and multilayers), and 4) membrane fabrication techniques and surface modification techniques. The current challenges and future research directions in materials and fabrication techniques for membrane technology applications in oil/water separation are also highlighted. Thus, this review provides helpful guidance toward finding more effective, practical, and scalable solutions to tackle environmental pollution by oils.

Separation Efficiency of Water/Oil Mixtures by Hydrophilic and Oleophobic Membranes Based on Stainless Steel Meshes with Openings of Various Sizes

This article is focused on development of hydrophilic and oleophobic composition which serves as a coating for substrate presented by stainless steel meshes with different sizes of their openings. Membranes obtained by dip-coating method are hydrophilic and oleophobic and this may be applied for efficient separation of organic liquids and water by simple and inexpensive gravitational separation. Investigations presented in the article show that the size of openings of meshes influence on the formation of hydrophilicity and oleophobicity of membrane, as well as the nature of used polymers, which serve as a coating, since membranes based on 400 mesh coated with Poly(diallyldimethylammonium chloride) (PDDA)/ pentadecafluorooctanoic acid (PFOA)/SiO2 demonstrate different wettability in regard to organic liquids of different densities. In particular, membrane based on mesh 400 coated with PDDA/PFOA/SiO2 exhibits strong oleophobicity to less dense non-polar organic solvents – kerosene, which does not penetrate the membrane, while more dense liquids, such as vacuum pump oil, are able to penetrate it, but the rate of penetration is rather slow, 10 ml per 21 min. Obtaining of membranes with uniform coating by hydrophilic-oleophobic compositions without clogging of their openings and creation of openings of required sizes for a particular case is also a subject of study of this article.

Enhanced oil removal from water in oil stable emulsions using electrospun nanocomposite fiber mats

Fibrous mats with hydrophobic and oleophilic properties have been fabricated and used as absorbents of oil from stable water in oil emulsions.

Oil removal from water–oil emulsions using magnetic nanocomposite fibrous mats

PMMA-based magnetic nanocomposite fibrous mats reach oil absorption efficiencies up to 90% in water–oil stable emulsions.