Preparation Of Graphene Via Diels-alder Reaction And The Adsorption Of Resveratrol

Graphene,a two-dimensional carbon nanomaterial with the unique structure,has been widely studied in electronic devices,medicine,energy,environmental protection and other fields due to its excellent property since it was reported in 2004.Although graphene material has been studied for more than 15 years,it has not yet achieved large-scale industrial applications.There are two bottleneck problems which restrict the widespread application of graphene material.On one hand,the large-scale preparation of high-quality graphene materials is difficult.On the other hand,the dispersion of graphene material in the matrix or solvent is unstable.Based on the above two bottleneck problems,the task successfully exfoliated functionalized graphene by Diels-Alder reaction of graphite with 4-maleimidophenol(4-HPM),which can be stably dispersed in common solvents.In addition,functionalized graphene exhibits excellent adsorption property for resveratrol.The details are as follows:(1)When graphene is used as the diene and 4-HPM is used as the dienophile,the Diels-Alder reaction is explored.Characterization methods prove that the Diels-Alder reaction can occur such as FTIR,XPS,Raman,EDS and TG.The TG and UV-Vis methods show that the grafting rate of 4-HPM is 3.8%-4.8%.(2)Through orthogonal experiments,the effect of reaction conditions on the Diels-Alder reaction between graphene and 4-HPM was explored,including reaction time,reaction temperature and solvent system.The results show that the optimal reaction system is N,N-dimethylformamide(DMF)as the solvent,and the reaction is carried out at 90? for 12h.At the same time,due to the introduction of 4-HPM,the dispersion stability of graphene materials in common solvents is significantly improved.(3)Based on the feasibility of the Diels-Alder reaction between graphene and 4-HPM,4-HPM was used as a dienophile reagent and intercalation reagent to exfoliate graphite and obtain 4-HPM grafted graphene.SEM and AFM methods demonstrate that the average number of graphene layers is 1-2 layers and the average lateral dimension is about 500-800nm.(4)In this study,the method for preparing graphene is mild and easy.It not only does not require acid and specific catalyst,but also can be produced on the large scale.Although the graphene yield of this method is 38%,the experimental materials can be recycled,including reaction solvent,unreacted graphite and unreacted 4-HPM.(5)The functionalized graphene exhibits excellent adsorption property for resveratrol.The adsorption of functionalized graphene to resveratrol conforms to pseudo-second-order kinetics and Langmuir model,and the maximum adsorption capacity is 292.4 mg/g.The adsorption capacity of functionalized graphene to resveratrol is 10 times higher than that of the reported macroporous adsorption resin.(6)Although the adsorption behavior of functionalized graphene to resveratrol is not affected by the ionic strength,it will be affected by the pH value.And the optimal pH is 4.0.After adsorption of resveratrol,the functionalized graphene can be washed with absolute ethanol,showing excellent regeneration performance.After 8 cycles,the adsorption capacity of the functionalized graphene can still be maintained above 200mg/g.