Decomposable Polyvinyl Alcohol-Based Super-Hydrophobic Three-Dimensional Porous Material for Effective Water/Oil Separation

Abstract

The development of the oil industry brings the critical problem of ocean pollution by oil spill or fossil fuels. The use of materials for water/oil separation is one of the effective approaches to solve this crisis. Polyvinyl alcohol (PVA) has been used to prepare water/oil separation materials. Currently, glutaraldehyde has been employed as the cross-linking agent, which is well known to be toxic and environmentally unfriendly. Moreover, it is difficult to deal with the disposal of the Across-linked material. Here, we propose a strategy of fabricating macroporous material which was prepared by PVA and sodium silicate (Na 2 SiO 3 ) in aqueous solution. Following through with the one-step method of sol−gel reaction of hydroxyl groups with trimethoxy(octadecyl)silane, the low surface energy substance was grafted on the macroporous material and a superhydrophobic macroporous membrane for water/oil separation was prepared. As oil sorbent, the as-prepared dried superhydrophobic PVA/Na 2 SiO 3 porous materials (PSD6S) have the adsorption capacity of 1.8−7.0 g/g for oil uptake, which depends on the type of oil liquid. Typically, the separation efficiency of this material could reach more than 99% even after 10 times of use without the help of ambient pressure. It is noteworthy that the as-prepared samples could be easily decomposable and dissolvable completely in acidic medium at a rapid rate.

Nature-Inspired Structures Applied in Heat Transfer Enhancement and Drag Reduction

“…There are lots of materials available for 3D printing, but the materials that can be processed by specific printing equipment are limited. It is difficult to process a variety of composite material structures at micro and nano scales simultaneously [137].…”

Janus Membranes with Asymmetric Wettability Applied in Oil/Water Emulsion Separations

“…[ 8 ] In order to solve these problems, a variety of original oil–water separation methods emerged, which usually separate oil/water mixtures by filtration and absorption. The materials for separating oil/water mixtures by filtration principle include meshes, [ 9,10 ] membranes, [ 11,12 ] filters, [ 13,14 ] film, [ 15,16 ] and so on; the materials for separating oil/water mixtures by absorption are porous materials, [ 17,18 ] powders/particles, [ 19,20 ] gels, [ 21,22 ] nanocomposites, [ 23,24 ] and so on. [ 3 ]…”

“…[8] In order to solve these problems, a variety of original oil-water separation methods emerged, which usually separate oil/water mixtures by filtration and absorption. The materials for separating oil/water mixtures by filtration principle include meshes, [9,10] membranes, [11,12] filters, [13,14] film, [15,16] and so on; the materials for separating oil/water mixtures by absorption are porous materials, [17,18] powders/particles, [19,20] gels, [21,22] nanocomposites, [23,24] and so on. [3] The oil/water mixture can be divided into three categories according to the diameter size: free oil: the diameter of droplet is greater than 150 µm; dispersed oil: the diameter of droplet is less than 150 µm and greater than 20 µm; emulsified oil: the diameter of droplet is less than 20 µm.…”

Simultaneous phase change energy storage and thermoresponsive shape memory properties of porous poly(vinyl alcohol)/phase change microcapsule composites

“…and carbonaceous materials 30 can be prepared by the emulsion template method, 31 freeze-drying method, 32 supercritical CO 2 foaming method 33 and physical stirring and foaming method. 34 Attributed to good biocompatibility, hydrophilicity, easy degradation and modification, porous PVA has been successfully applied as adsorption materials in filtration 35 and oil-water separation, 36 and as medical materials in drug release, 37 tissue engineering scaffolds 38 and wound dressings. 39 As supporting skeleton material, PVA with porous structure was also used in various phase change composites to prevent the leakage of solid-liquid PCMs, 40 showing the advantages of good mechanical flexibility, higher energy storage density, longer cycling life and lower cost.…”