| In recent years,frequent occurrences of water pollution caused by oil spill and chemical leakage have led to severe environmental destruction on a global scale,which lead to the production of human and habitat of life has been severely damaged.Hence,how to quickly and efficiently conduct oil/water separation from oil-polluted water sources has become an urgent problem to be solved.There are many methods that have been reported to deal with oil/water separation,for example:skimmers,solidifiers,dispersants,bioremediation,controlled burning,physical diffusion,and adsorption materials,etc.However,most of them still have some limitations for practical application including high cost,low efficiency,poor recycling ability,hazardous by-product,etc.In recent years,Porous polymer-based monoliths with remarkable hydrophobicity have attracted great interest in the field of oil/water separation,because only oil is adsorbed while water is completely repelled outside the monoliths.On the basis of previous pioneering works,it is of great significance to develop novel porous polymer-based monoliths with superhydrophobicity and superoleophilicity for high-efficiency oil/water separation.In this paper,superhydrophobic and superoleophilic porous reduced graphene oxide/polycarbonate(RGO/PC)monoliths(RGO content of 1 wt%)were first fabricated by thermally impacted nonsolvent induced phase separation(TINIPS)method with the raw materials of polycarbonate(PC)and reduced graphene oxide(RGO).The microstructure and performance of RGO/PC porous monoliths were characterized by scanning electron microscopy,Fourier transform infrared spectroscopy,specific surface area and pore size analyzer and contact angle tester.The conclusions are listed as follows:(1)RGO/PC porous monoliths possess a novel micro-nanoscale binary structure.At low magnification,the morphologies of porous RGO/PC porous monoliths present a coral-like structure consisting of numerous granules.The size of granules has a random distribution ranging from 7 to 20μm.Based on high-magnification SEM images,these micron-sized granules are composed ofthree-dimensionalinterconnectednest-likeporousstructure,inwhich different-sized nanofibers interlace with each other so as to form continuous skeleton and nanoscale pores;(2)RGO/PC porous monoliths with water contact angle of156°and oil contact angle of 0°,excibiting an excellent superhydrophobicity and superoleophilicity;(3)The superhydrophobic and superhyperhydrophilic properties of the RGO/PC porous monoliths enable it to selectively separate the oil in the oil-water mixture;(4)RGO/PC porous monoliths have better adsorption capacity for different kinds of oils and organic solvents and the saturated adsorption capacity can reach to 5.47-15.8 times for its own weight.The cycle performance of the adsorbed porous RGO/PC monolith was tested and the results show that after ten cycles,the RGO/PC monolith can still maintain a good adsorption capacity.Subsequently,the effects of different contents of RGO on the structures and properties of RGO/PC porous monolith were studied.The results show that:(1)With the increase of RGO loading(0.5-2 wt%),pore size exhibits an increasing trend.It can be ascribed to the enhanced supporting effect of RGO on porous skeleton.When the filler loading reaches 3 wt%,more RGO nanosheets agglomerate together through strong van der Waals force andπ-πstacking interaction,leading to the reductions in supporting effect and pore size.Therefore,when the content of RGO was 2 wt%,RGO/PC porous monolith possess the largest pore size distribution and porosity(91.3%).(2)Because the microstructure of material has a decisive role in its macroscopic hydrophobicity,porous RGO/PC monolith with RGO content of 2 wt%has the largest water contact angle(water contact angle was 161~o)and the adsorption capacity for different oils and organic solvents reaches the largest(saturated adsorption capacity can reach to 7.88-17.57 times for its own weight). |
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