3D Porous PVA-based Super-hydrophobic Materials For Water/oil Separation

With the development of petroleum industry,the oil spill caused by oil extraction and the transport of mineral oils is making the problems of marine pollution more and more serious.The issues have attracted the public's attention to the water pollution problems.For the sake of solution of the problems,the method of water/oil separation could effectively solve this crisis.And the leaked oil on the surface of the ocean could be collected and reused.There are still some deficiencies among the researches results of the materials for water/oil separation.That is the separation process would be operated effectively while mostly need a certain external force.Furthermore,it is difficult to give a suitable post-processing which would usually cause a second pollution.In this work,a strategy to prepare materials with super-hydrophobic surface and three-dimensional porous structure for water/oil separation via sol-gel method was reported.In this study,sodium silicate which is non-toxic and easily accessible was employed as crosslinking agent of PVA.Therefore,the PVA-based hydrogels cross-linked by sodium silicate were prepared via sol-gel and gels were obtained following a process of freeze-drying method.After that,octadecyl trimethoxy silane was employed to graft on the gels to prepare super-hydrophobic materials with three-dimensional structure and good mechanical properties.As a result,the as-prepared materials could selectively adsorb the oils and organic solvents in the water/oil system for different types of oils or organic solvents and had the maximum value of adsorption capacity of 7.0 g/g.Furthermore,the as-prepared materials could conduct the separation for water/oil separation under atmospheric pressure and the oils could be collected and reused.The separation process could be done efficiently with the efficiency of more than 99%even after 10 times.Moreover,the samples could deal with surfactant-stabilized emulsion efficiently.In addition,the as-prepared samples could be decomposed and dissolved in strongly acidic solution after used which could reduce the fees on the post-processing and avoid the secondary pollution.Therefore,the as-prepared materials have great potential to apply in the water treatment.