Fabrication And Oil/Water Separation Characteristics Of Superhydrophobic Porous PC-based Composites

With the rapid development of global industry,the demand for oil and chemical products for each country shows a sharply upward trend.At the same time,oil spills and industrial organic emissions have caused serious pollution to water resources and the environment.Therefore,the sewage treatment has importantly practical significance to human production and life.The traditional methods of treating oil pollution mainly include electrochemistry,flotation,centrifugation,filtration,gravity separation and in situ combustion,etc.However,most of the above methods due to the use of a long time,cumbersome operation,high cost and low separation efficiency are greatly limited in practical application.In recent years,the superhydrophobic materials show a broad application prospect in the field of oil/water separation and have attracted the attention of domestic and foreign researchers owing to its special wettability.The superhydrophobic polymer three-dimensional porous materials can selectively adsorb oil from oil/water mixture to achieve efficient oil/water separation because of its superhydrophobic surface,low density,high porosity,large specific surface area and interconnected pore structure,etc.Thus,they stand out from many materials for oil/water separation.In this paper,the superhlydrophobic PC-based porous composite(OMWNTs content of 1 wt%)was prepared by thermally impacted nonsolvent induced phase separation(TINIPS)with the raw materials of polycarbonate(PC)and carboxylic multi-walled carbon nanotubes(OMWNTs).The microstructure and the oil/water separation performance of PC/OMWNTs porous composite were characterized by scanning electron microscopy,specific surface area and pore size analyzer,Fourier transform infrared spectroscopy and contact angle tester.The results and conclusions are listed as follows:(1)The water contact angle of porous composite was 159 o and the oil contact angle was close to 0o,so the material had excellent superhydrophobic and superoleophilic characteristic;(2)The microstructure of the porous composite was composed of micro-nanostructures.The morphology of the microscale was fromed by the accumulation of coral-like particles with 3-12 ?m in diameter.The morphology of the nanoscale showed that these corals were composed of the uneven thickness and staggered connection of nanofibers and the pore size distribution was relatively wide;(3)The OMWNTs was encapsulated into the PC nanofiber skeleton by physical action in phase separation process to play a supporting role,finally resulting in high porosity;(4)The superhydrophobicity and superoleophilicity of the porous composite allowed it to selectively adsorb oil from oil/water mixture to achieve oil/water separation;(5)The porous composite had good adsorption capacities for various organic solvents and oils.The saturated adsorption capacity could reach 8 to 13 times of its own weight and the composite still had a good adsorption capacity after ten times of adsorption.As a result,the porous composite showed excellent cycle performance.Subsequently,the effects of different contents of OMWNTs(1-4 wt%)on the structures and properties of PC/OMWNTs porous composites were investigated.The results show that:(1)When the contents of OMWNTs were in the range of 1-3 wt%,the increase of filler made the nanofiber skeleton of the porous composite thinner,the size of pores larger and the amount of pores increased.As the contents of OMWNTs continued to increase(4 wt%),the nanofiber skeleton of the porous composite began to become thicker,the size of pores become smaller and the amount of pores decrease.Therefore,PC/OMWNTs porous composite could obtain the best porous structure when the content of OMWNTs was 3 wt%.(2)Because the structure of the porous composite had a decisive influence on the oil/water separation performance,the superhydrophobicity of 3 wt% porous composite was the best(Water contact angle was 164°)and the saturated adsorption capacities of oil and organic solvent reached the maximum(the saturated adsorption capacity of soybean oil could reach 14.8 times).