| In recent years,it is the increasing frequent exploitation of crude oil in the sea and the rapid development of petrochemical enterprises that caused the frequent occurrence of oil leakage accidents and the free discharge of wastewater,which not only caused huge economic losses,but also brought fatal harm to ecological environment.Thus,oil/water separation has aroused great attention all over the world.For dealing with some drawbacks of traditional filter membrane material,it is important to study the fabrication of superwetting adsorptive materials and their performances in oil/water separation,which not only pocess high research values but also pocess significant practical values.Among them,the most important value is that the "adsorptive" superwettable material avoids a series of high energy consumption and tedious operation processes involved in the process of oil/water separation,such as,collecting the oil-water mixture first,and then pouring onto the surface of the "filter" superwetting materials to separate it.In addition,the layer with both filtration and adsorption functions for free and emulsified oil/water separation,which not only can avoid the complicated film making process,but also can breaks through the limitation of smaller nanoscale pore size on flux in the process of emulsions separation.In order to satisfy the need of efficient and rapid emulsion separation,developing superwetting adsorptive materials for oil-in-water or water-in-oil emulsion separation has become a new research content.Therefore,this paper was focused on preparation of several superwetting adsorptive materials,such as superhydrophobic palygorskite coated sponge,coconut shell layer and sand layer,and exploring their performances and mechanisms of oil-in-water and water-in-oil emulsions separation.The main contents are summarized as follows:(1)We successfully prepared superhydrophobic/superoleophilic sponges via the simple dip-coating method by covering the octadecyltrichlorosilane-modified palygorskite onto the skeleton surface of polyurethane sponge.The sponge showed better adsorption capacity for vavious oils,good recycling performance,superior acid-alkali-salt resistance and hot water repellence.Furthermore,the superhydrophobic/superoleophilic sponge also can be combined with the vacuum pump,which could be used for continuous,rapid and efficient separation of free oil/water mixtures.In addition,the separation of oil-in-water emulsions can be achieved by rapidly stirring the sponge into the emulsions,and the separation efficiency is up to 99.87%.In the end,the mechanism of oil-in-water emulsion separation was detailedly investigated.(2)We used the biomass material coconut shell to make a layer by simple smashing,washing and stacking menthod.The coconut shell layer can be used as a filter material with excellent underwater superoleophobicity,and is capable of separating a series of free oil/water mixtures.The coconut shell layer can also be used as an adsorptive material with excellent underoil superhydrophilicty,achieving separation of various water-in-oil emulsions.Moreover,The separation efficiencies of coconut shell layer for both free oil/water mixtures and water-in-oil emulsions separation are all more than 99.90 %,and the corresponding fluxes are higher than 1620 L/m2 h.In addition,the coconut shell layer shows better recycling performance for water-in-oil emulsions separation.Finally,the mechanism of water-in-oil emulsion separation was also discussed.(3)We also used the desert sand to make a layer by the simple stacking method.The sand layer pocess excellent underoil superhydrophilicity.The sand layer can separate various types of water-in-oil emulsions with high flux up to 2342 L/m2 h and the separation efficiency up to 99.99 % by gavity.This is the advantages that traditional filter materials do not pocess in the process of water-in-oil emulsions separation.At last,the separation mechanism of water-in-oil emulsion was also explored. |
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