Research On The Construction And Performance Of Super-hydrophobic And High-strength Oil-water Separation Materials

Graphene aerogel(GA)has attracted a lot of attention due to its three-dimensional(3D)interconnecting framework,high specific surface area,low density and impressive adsorption capacity.This thesis systematically researches the preparation,modification as well as large-scale controllable preparation of GA,and focuses on its application in the continuous and efficient oil/water separation to solve the problem of water pollution.Firstly,we explored the effect of L-ascorbic acid on the preparation process of GA at different pH graphene oxide(GO).Scanning electron microscopy(SEM),X-ray diffraction(XRD),Thermogravimetric analysis(TGA),Fourier transform infrared spectroscopy(FT-IR),resistivity test and surface hydrophobicity were used to characterize the microstructure and surface properties of GAs.And the differences between GA prepared at different pH in oil and dyes adsorption was compared and explained.Our research has provided a facile approach to obtain the robust GAs with controllable surface properties for various water purification applications just by adjusting pH of GO.After that,we also explored the effect of basic reductant ethylenediamine on the preparation of GA at different pH values GO.We found that there was no significant difference between the GA obtained at different pH reduction by ethylenediamine.In order to reduce the production costs of GA and enhance the mechanical toughness of GA,the superhydrophobic reduced graphene oxide-wrapped melamine sponge(RGO-MS)possessing good adsorption capacity was successfully prepared using low-temperature thermal treatment method under reduced atmosphere with MS as a substrate and GO as a surface modifier.RGO-MS was investigated by XRD,Raman spectra,FT-IR spectra,X-ray photoelectron spectrometer(XPS)and SEM.The mechanical property,hydrophobicity,and oil/water separation efficiency of RGO-MS were also explored.The results revealed that reduced graphene oxide(RGO)coating was closely linked to MS skeleton by chemical bond.RGO-MS possesses good recyclability,outstanding adsorption capacity and oil/water separation capacity including floating oil and heavy oil underwater,and exhibits extremely high separation efficiency up to 6×106 L·m-3·h-1 and 3.6×106 L·m-3·h-1 in non-turbulent and turbulent water/oil system,respectively.This method provides a new idea for the preparation of superhydrophobic adsorbents,and really improves some shortcomings of GA.It is difficult to achieve controlled preparation due to the limition of the equipment size.In order to achieve large-scale controlled preparation of adsorbents,the superhydrophobic RGO-MS is fabricated via a facile and green surface modification method with low temperature chemical reduction using GO modification the surface of MS.The obtained RGO-MS was investigated by XRD,Raman spectra,FT-IR spectra and SEM.The hydrophobicity,the mechanical property,oil adsorption capacity,reusability and oil/water separation efficiency of RGO-MS were also explored.The RGO coating was closely linked to MS skeleton.In addition,RGO-MS possesses outstanding adsorption capacity for floating oil and heavy oil underwater,and could maintain ultrahigh adsorption capacity even after 50 adsorption-squeezing cycles which is as high as 90%of its initial adsorption capacity.Moreover,RGO-MS exhibits extremely high separation efficiency up to 4.5×106 L·m-3·h-1 and 3×106 L·m-3·h-1 in non-turbulent and turbulent water/oil system,respectively.Therefore,large-scale controlled preparation of RGO-MS is of great significance for dealing with the large-scale oil and organic solvents pollution.