| With the continuous development of global science and industrial technology,people consume more and more oil,and the leakage of oil and dangerous organic solvents occurs more and more frequently.The harm to the ecological environment and human life and health can not be ignored,there is an urgent need to find effective treatment methods.The development of green and efficient low-cost adsorbents is one of the effective treatment methods.Three-dimensional graphene aerogel has become a research hotspot in the field of efficient water-oil separation in recent years because of its high specific surface area,high hydrophobic lipophilicity and excellent chemical and thermal stability.Hydrothermal reduction of graphene oxide is one of the simplest and most environmentally friendly methods for preparing graphene aerogel.The shape and volume of the aerogel can be easily adjusted by changing the size of the reaction container,which indicates the possibility of large-scale production for commercial applications.However,the pure graphene aerogel prepared by hydrothermal method has high brittleness,easy to collapse and poor mechanical properties,which limits its wide application.In this study,three-dimensional TKF-RGO aerogel,KGM-RGO flexible interpenetrating network aerogel and octadecyl trichlorosilane(OTS)superhydrophobically modified OTS@KGM-RGO aerogel with excellent comprehensive properties were prepared by using low-cost kapok fiber(KF)and konjac glucomannan(KGM)as supporting framework,and their structures were characterized.Their adsorption properties and adsorption kinetics for oil and organic solvents were studied.The main contents are as follows:(1)A series of three-dimensional kapok fiber/ reduced graphene oxide(TKF-RGO)aerogels with different TKF/RGO mass ratios were prepared by simple and green one-step hydrothermal method using ascorbic acid as reducing agent.The activated kapok fiber as the supporting framework improved the mechanical properties of the adsorbent and wound with reduced graphene oxide to form a three-dimensional porous structure.Among them,the adsorption capacity of TKF-RGO-40% aerogel with the best comprehensive performance for all kinds of common oils and organic solvents was between 28-62 g/g,and the adsorption equilibrium time for pump oil,engine oil,soybean oil and diesel were 11 min,6 min,4 min and 30 s,respectively.The adsorption process was more consistent with the quasi-second-order adsorption kinetics.The water contact angle of TKF-RGO-40% reached 134.3 ° and the pump oil could be completely absorbed in 1.2 s.After 10 adsorption cycles,TKF-RGO-40% aerogel had a recycling efficiency of 94% for pump oil and engine oil,and 99% for diesel and petroleum ether.In addition,through the connection with the vacuum system,it was proved that the sample had excellent continuous water-oil selectivity,which was beneficial to the continuous separation of water-oil mixing system.(2)A series of flexible network aerogels based on the interpenetration of konjac glucomannan(KGM)and reduced graphene oxide were prepared by two-step hydrothermal method.The addition of KGM as a flexible skeleton made different proportions of composite aerogels showed different toughness.Compression tests showed that KGM-RGO aerogel had better mechanical properties than RGO aerogel.The compressible elasticity of KGM-RGO-2 was of great significance for the reuse of composite aerogel in adsorption.The adsorption capacity of the prepared KGM-RGO-2 aerogel to various common oils and organic solvents was between 46-85 g/g.KGM-RGO-2 aerogel could be desorbed by extrusion or extractant.and its initial adsorption capacity could still maintain 94% utilization after 10 cycles.The adsorption of pump oil,soybean oil,diesel and petroleum ether reached equilibrium at 90 s,75 s,30 s and 15 s,respectively.The adsorption process of KGM-RGO-2 aerogel was fitted by quasi-first-order kinetic equation and quasi-second-order kinetic equation respectively.The results showed that the adsorption process of high viscosity organic compounds was mainly physical adsorption,while the adsorption of low viscosity organic compounds was mainly chemical adsorption.(3)On the basis of the previous chapter,using OTS as surface modifier,KGM-RGO flexible composite aerogel with interpenetrating network structure was superhydrophobically modified by simple solution dipping method,and OTS@KGM-RGO aerogel with water contact angle up to 150.3 ° was successfully prepared.OTS successfully modified the sample by consuming the hydroxyl groups on the surface of KGM-RGO aerogel for hydrolysis and self-assembly,and formed a super-hydrophobic layer on the surface of the sample,which made the surface rougher and reduced the surface energy of the sample.The adsorption capacity of OTS@KGM-RGO aerogel was higher than that of KGM-RGO aerogel,and the adsorption capacity for all kinds of common oil and organic solvents was between 51-91 g/g.In addition,with the help of the connection with the vacuum system,the continuous water-oil selectivity of the sample was tested,and the results showed that it had excellent continuous water-oil separation ability. |
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