The Interface Construction Of Composites Based On Graphene Oxide For Application Of Separation And Analysis

In the separation or analysis applications of targets,most of the usedmaterials need to be directly contact with the target,so the materials must have good physical and chemical properties.As one ofthe research focuses in recent years,graphene oxide has many excellent properties,such as large specific surface area,amphipathy and rich oxygen-containing functional groups.Wherein the large specific surface area imparts a strong load capacity to graphene oxide,amphipathy makes graphene oxide easily dispersed in most solvents and rich oxygen-containing functional groups that have active chemical properties make graphene oxideeasy to be modified.Many molecules and polymers can be lightlybonded to the surface of graphene oxide by covalent or non-covalent bonds to produce grapheneoxide-based composites.Compared with the raw materials,the properties of graphene oxide-based composites have been improved remarkably,which lead to a wide prospect in the separation and analysis of targets.In this paper,based on technologies of molecular imprinting,electrochemistry,bio-inspiration,membrane separation,quantum dots fluorescence and so on,graphene oxide(GO)was reacted with polymers and nanomaterials to construct the interface of GO-based composites.The structure and morphology of the prepared composites were characterized,and the ability of separation or analysis applications for targets was discussed deeply.The main research contents and results are as follows:(1)Using graphene oxide/silver nanoparticles(GO/AgNPs)composites as the substrate and sunset yellow as the template molecule,GO/AgNPs-MIPs were synthesized on thesurface of composites by surface imprinting technique.The final synthesized products were employed to modify glassy carbon electrodesby a drop-casting method,thus the prepared electrochemical sensor was used forthe detection of sunset yellow.The characterization data suggested that GO/AgNPs-MIPs had been successfully synthesized.The effect of pH,used amount and incubation timeon the process of detecting sunset yellow was discussed.Under optimal conditions,the electrochemical sensor had linear detection range in 0.10-12.00 ?mol L-1andthe detection limit was 0.020 ?mol L-1.Finallythe electrochemical sensor was successfully applied to the actual detection of sunset yellow in four common soft drinks.(2)According to mussel-inspired conception,polydopamine(PDA)layers were constructed on the surface of the mixed cellulose estermembrane by simple self-polymerization.Graphene oxide membrane was then uniformly formed on the PDA modified membrane by vacuum filtration of graphene oxide solution.The prepared GO/PDA membrane was employed in the separation of oil/water emulsions.The covalent interactions betweenGO and PDA that made the preparedGO/PDAmembrane highly stable were confirmed.The separation performance of the Tween 80-stabilized oil/water emulsions was investigated on the GO/PDA membrane.The obtained results showed that the membrane had good separation ability,anti-fouling property and recycle ability towards Tween 80-stabilized oil/water emulsions.(3)By simple hydrothermal methods,graphene quantum dots manganese dioxide nanosheetswere synthesized using graphene oxide,potassium permanganate and sodium dodecylbenzenesulfonate as raw materials,respectively.Graphene quantum dots and manganese dioxide nanosheets were combined into a“turn off-on” fluorescence sensor,which was used to analyzeascorbic acid.The results show that the graphene quantum dots and manganese dioxide nanosheets have been successfully prepared.Under optimal conditions,the prepared fluorescence sensor exhibited advantages of fast response time,simple preparation process,high sensitivity and selectivity,and has potential application value and significance.Finally,the fluorescence sensor was successfully in thedetermination of ascorbic acidin three fruit juices.