Upcycling Waste Pine nut Shell Membrane for Highly Efficient Separation of Crude Oil-in-Water Emulsion

Abstract

Discharge of oily sewage and frequent oil spills have caused serious harm to human production, life, and ecological environment. Due to the presence of a large number of surfactants in water, these oil-water mixtures are easy to form oil-in-water emulsion, which is difficult to separate by traditional methods. At the same time, the watersoluble pollutants such as dyes and heavy metal ions in oily wastewater also cause great harm to the human body and the environment. A pine nut shell is a kind of common domestic waste material. Herein, an underwater superoleophobic pine nut shell membrane (PNSM) was prepared by the simple pumping filtration method, which realized the separation of oil-in-water emulsion and adsorption of dyes and heavy metal ions. In addition, the filter membrane can be used for separating corrosive emulsions of strong acid, strong alkali, and 3.5% NaCl solutions (simulated seawater). Besides, the PNSM showed excellent toughness and flexibility. Due to the abovementioned performance, this cost-efficient and environmentally friendly membrane can be a promising candidate for multifunctional oily water remediation.

Current research situation and future prospect of superwetting smart oil/water separation materials

“…37 Alternatively, materials with superhydrophilic/superoleophobic ability are known as "waterremoving" materials. [38][39][40][41][42][43] Due to its ultrahigh separation performance and excellent reusability, wettability-regulated separation technology is superior to conventional separation methods, and thus is regarded as the best choice for treating oil spills and purifying oily wastewater. [44][45][46] The rst "oil-removing" material was reported by Jiang et al in 2004, which successfully achieved gravity driven oil/water separation.…”

Green Preparation of a Carboxymethyl Cellulose-Coated Membrane for Highly Efficient Separation of Crude Oil-In-Water Emulsions

“…With industrial production, a large amount of complicated oily wastewater is discharged, which not only causes serious water pollution but also poses a severe hidden danger to human health. − Oil-in-water emulsions are particularly difficult to separate due to the presence of surfactants . In recent years, benefiting from the unique advantages of membranes, researchers have conducted extensive research on superwetting filtration membranes for oil-in-water emulsion separation. − Compared with conventional separation technologies including sedimentation, oil skimming, oil absorption, , and gravity separation, membrane technology stands at a higher position because of its simple preparation and high separation efficiency. − However, the adhesion of organic solvents on the membrane surface during the separation process can lead to clogging of the membrane pores, thus affecting the separation flux. − Therefore, it is a huge challenge to prepare high-performance membranes with antifouling properties.…”

Robust Superhydrophobic/Superoleophilic Filter Paper with TiO2 Nanoparticles for Separating Oil–Water Mixtures and Surfactant-Stabilized Water–Oil Emulsions

“…Highly efficient oil–water separation is urgently required in multiple agricultural and industrial processes associated with energy, water, and environmental security. − Traditional oil–water separation techniques such as skimming, adsorption, air flotation, centrifugation, and precipitation can effectively separate immiscible oil–water mixtures. − However, these methods pose challenges such as low separation efficiency, high energy costs, complex operations, and secondary contamination. Recently, materials with special wettability are gaining increasing attention because of their promising applications in oil–water separation; membranes with excellent wettability can achieve efficient oil–water separation. − Yan et al prepared an Fe@GA metal-phenolic network (MPN) film using Fe III and gallic acid (GA) and deposited the film on the surface of cotton fabrics. Fe@GA MPNs exhibit excellent hydrophobicity and can be used in immiscible oil–water mixture systems to separate heavy oil from water through simple filtration methods.…”