Coupling Underwater Superoleophobic Membranes with Magnetic Pickering Emulsions for Fouling-Free Separation of Crude Oil/Water Mixtures: An Experimental and Theoretical Study

Abstract

Oil/water separations have become an area of great interest, as growing oil extraction activities are increasing the generation of oily wastewaters as well as increasing the risk of oil spills. Here, we demonstrate a membrane-based and fouling-free oil/water separation method that couples carbon nanotube-poly(vinyl alcohol) underwater superoleophobic ultrafiltration membranes with magnetic Pickering emulsions. We demonstrate that this process is insensitive to low water temperatures, high ionic strength, or crude oil loading, while allowing operation at high permeate fluxes and producing high quality permeate. Furthermore, we develop a theoretical framework that analyzes the stability of Pickering emulsions under filtration mechanics, relating membrane surface properties and hydrodynamic conditions in the Pickering emulsion cake layer to membrane performance. Finally, we demonstrate the recovery and recyclability of the nanomagnetite used to form the Pickering emulsions through a magnetic separation step, resulting in an environmentally friendly, continuous process for oil/water separation.

Tailoring surface charge and wetting property for robust oil-fouling mitigation in membrane distillation

“…This mechanism, namely the hydration force, has been a pivotal guiding principle for developing fouling resistant membranes and antioil-adhesion surfaces [39,40]. Although the effect of hydration force is indeed prominent, there is another important factor that plays a critical role in oil-membrane interaction but is nonetheless often neglected in developing underwater oelophobic surfaces [28,[41][42][43].…”

Recent Progress in Fabrication and Applications of Superhydrophobic Coating on Cellulose-Based Substrates

“…On the other hand, the smartly self-healing surface properties, and rational strategies for mechanical abrasion make these robust superhydrophobic fabrics more reliable for practical applications and commercialization in clothing industries. In this section, we mainly focus on the development of durable cellulose-based materials with superhydrophobic properties in oil-water separation, self-cleaning and asymmetric fabrics [123,124,125,126,127,128,129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144]. …”

“…Hydrophobic porous materials have gained tremendous interests because of their capability of selective absorption of oils/organic solvents while completely repelling water [129,130,131,132,133,134,135,136,137,138,139,140,141,142,143,144]. Inspired from mussel, Huang’ group fabricated the superhydrophobic sponge by decorating polydopamine nanoaggregates with n-dodecylthiol motifs on the skeletons of PU sponge [129].…”

“…This will lead to a relatively stable system of oil-water mixture. Recently, Dudchenko et al demonstrated a method of membrane-based and fouling-free oil-water separation that couples carbon nanotube-poly underwater superoleophobic ultrafiltration membranes with magnetic pickering emulsions [138]. Its advantages are that it shows very high stability with the temperature change, and it is resistant to electrolyte, and stable in a wide range of pH solutions and polar solvents.…”

Tunable Wettability of Electrospun Polyurethane/Silica Composite Membranes for Effective Separation of Water‐in‐Oil and Oil‐in‐Water Emulsions

“…[14][15][16][17][18] For example, Jin et al reportedanovel superhydrophilic and underwater superoleophobic poly(acrylic acid)-grafted polyvinylidene fluoride (PVDF) membrane for the effective separation of oil-in-water emulsions. Therefore, the separation of an oil/water emulsion is always difficult and challenging.…”