Prewetting Polypropylene-Wood Pulp Fiber Composite Nonwoven Fabric for Oil–Water Separation

Abstract

The removal of oil from the water surface is vital to protect the environment and living organisms against the threats posed by industrial oily wastewater and offshore oil spills. High cost, low efficiency, and environmental pollution limit the widespread use of the commercial methods of oil−water separation. In this study, the prewetting polypropylene-wood pulp fiber composite nonwoven fabric (PWNF) has been used in the gravity-driven separation of the oil− water mixture. The prewetting PWNF displayed superior underwater oleophobic properties, and the underwater kerosene contact angle was 137.65°± 4.27°. The oil−water interfacial tension in the microchannels among the PWNF fibers prevented the oil from passing through the microchannels; however, it allowed the passage of water. The PWNF membrane maintained an excellent oil−water separation performance after repeated separation and long-term soaking cycles. The separation membrane maintained 75% and 50% of the initial separation performance after 40 repeat cycles and water immersion for more than 20 days, respectively. The separation rate of the PWNF membrane was also investigated as a function of salt solution concentration, temperature, and pH. Meanwhile, the influences of prewetting time, prewetting temperature, and different dyeing condition of the mixture on the separation rate were clarified. The destruction of the oil−water contact interface was suggested as the main failure mode of the developed PWNF separation membrane. The maximum kerosene height that the PWNF separation membrane could sustain was 800 mm. The obtained results confirmed that the PWNF separation membrane exhibited the high potential of widespread use in various environments for achieving efficient and stable separations, especially for the oily wastewater treatment.

Composited Gels from Nature Growing Scaffold: Synthesis, Properties, and Application

“…With the intention to demonstrate the potential application of the biopolymer-based elastic gels, the PAN50/Fe@CSP was used for oil/water separation. The static water contact angle (WCA) test was characterized the hydrophobicity of the materials, and the PAN50/Fe@CSP was a hydrophilic sample as the main constitution of the material was saccharides. − First, we used the lignin solution as a biobased hydrophobic polymer to deposit on the surface of the PAN50/Fe@CSP, in order to immobilize the deposited lignin and prepare a hydrophobic sample, following by a classic protocol, chemical vapor deposition (CVD) for further modification. The WCA of the modified PAN50/Fe@CSP was about 140°, which was hydrophobic enough for oil/water separation.…”

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

“…57,[89][90][91][92][93] Furthermore, prewetting induced smart materials can well realize on-demand oil/ water separation and even emulsion separation without any continuous external stimulus. [61][62][63][64] Simultaneously, it is well known that there are two important factors for the construction of superwetting surfaces, i.e., the surface energy of the materials and the surface microstructure.…”

“…59,60 On the other hand, smart materials induced by a prewetting strategy can also perfectly enable on-demand oil/water separation, even emulsions separation without any continuous external stimulus. [61][62][63][64][65] Compared with stimulus responsive materials, prewetting induced smart materials oen exhibit the following advantages: (a) the separation pattern can be quickly switched between the "water-removing" type and the "oil-removing" type; (b) prewetting induced smart materials avoid the use of expensive and environmentally polluting low-surface-energy substances, such as uorosilanes used to prepare superhydrophobic surfaces; and (c) stimulus responsive smart materials are only limited to some specic organic or inorganic substances that are pHsensitive, heat-sensitive, photosensitive, etc., while prewetting induced smart materials can use some materials with superamphiphilic performance and certain water or oil retention property. It is worth noting that stimulus responsive and prewetting induced smart materials have opened up a whole new dimension in the research eld of oil spills and oily wastewater treatment.…”

The Fabrication of Oleophobic Coating and Its Application in Particulates Filtration

“…Oleophobic materials are widely adopted for oil-water separation [22][23][24]. For example, hydrophilic and underwater oleophobic coatings or structures were applied on PVDF membranes.…”