Filter Paper with Selective Absorption and Separation of Liquids that Differ in Surface Tension

Abstract

Superhydrophobic and superoleophilic filter paper was successfully prepared by treating commercially available filter paper with a mixture of hydrophobic silica nanoparticles and polystyrene solution in toluene. Applications of the filter paper in separating liquids with low surface tensions such as oil and ethanol from water were investigated in detail. The oil uptake ability of the superhydrophobic filter paper was evaluated and the results show that the filter paper can selectively adsorb oil floating on a water surface or in aqueous emulsions. Furthermore, filtration of mixtures of oil and water through the paper can reduce the water content in the oil. Additionally, the filter paper can also extract ethanol from homogeneous aqueous solution.

Recent developments in polymeric superoleophobic surfaces

“…They realized filtration or absorption of oils from water selectively and effectively. [137][138][139][140][141][142][143][144][145] However, this type of materials is easily fouled even blocked up by oils because of their intrinsic oleophilic property. The adhered oils seriously affect the separation efficiency, service life, and the recycle of oils and materials.…”

Cellulosic Substrates for Removal of Pollutants from Aqueous Systems: A Review. 3. Spilled Oil and Emulsified Organic Liquids

“…Closely related to density and pore volume is the ability of a sorbent material to float on water, which has been listed as a desirable or even an essential property for oil cleanup by many authors (Fuller 1971;Pushkarev et al 1980;Ericsson et al 1985;Pate 1992;Deschamps et al 2003a;Wang et al 2010;Korhonen et al 2011;Likon et al 2011;Moura and Lago 2011). Presumably, if a sorbent material cannot float on water, then there is a likelihood that it will sink, together with any sorbed oil.…”

“…In particular, lower values of  c have been associated with a lower tendency to absorb water (Tavisto et al 2003;Baltazar-y-Jimenez and Bismarck 2007). Many authors have listed a low tendency to absorb water as a desirable or even essential attribute of oil-spill-control sorbent materials (Pate 1992;Choi 1996;Sun et al 2002Sun et al , 2003Rethmeier and Jonas 2003;Wei et al 2003;Suni et al 2004;Wang et al 2010;Choi et al 2011). Also, in some cases, a correlation has been noted between fibers' tendency to exclude water and their tendency to float on water Rethmeier and Jonas 2003;Wang et al 2010;Korhonen et al 2011;Likon et al 2011).…”

Vibrations and Spatial Patterns Change Effective Wetting Properties of Superhydrophobic and Regular Membranes

“…The wetting properties depend on the pore size, surface roughness and surface agent used. Stainless steel and copper meshes, and filter paper [40], were commonly used to separate mixtures in which oil is layered over water. If one of the phases in oil-water mixture is dispersed in the other as small droplets (smaller than the pore size) the meshes become ineffective.…”