Study On The Removal Of Organic Dyes From Aqeous Solution By Magnetic Graphene Composites

As emerging carbon nanomaterials,graphene has attracted more and more attentions.The chemical exfoliated graphene has large surface area and abundant surface functional groups which offer it with extremely strong adsorption properties,leading to great application potential in preconcentration and separation of pollutants.At present,there are still some obstacles for the applications of graphene,including the easily aggregation in water and difficult to separate.The preparation of novel graphene based composite materials with good dispersibility and easier separation properties will greatly promote graphene for the practical application in water treatment.In this project,a few of gaphene based composites were fabricated and applied for the removal of organic byes form aqueous solution.Effects of solution pH,adoption amount and adsorption time on the adsorptive removal of organic dyes were investigated.(1)Chitosan wrapped zinc ferrite-graphene oxide composites(ZnFe2O4@CS/GO)for the removal of methylene blue(MB)from aqueous solution.In this study,magnetic zinc ferrite was firstly wrapped with a layer of chitosan and then chemically bonded to graphene to form the ZnFe2O4@CS/GO composite materials.Then,the ZnFe2O4@CS/GO composites were applied as sorbents for the removal of methylene blue from aqueous solution.Effect of solution pH,adsorbent amount,adsorption time and temperature on the removal of MB were systematically investigated.The results showed the adsorption of MB onto the ZnFe2O4@CS/GO is favorable at basic conditions,the adsorption kinetics followed the pseudo-second kinetic model and the adsorption isotherms are better described by the Langmuir model.The ZnFe204@CS/GO showed an excellent adsorption capacity toward MB,indicating the ZnFe204@CS/GO can be novel nano-sorbents for the application in the preconcentration and removal of organic dyes from large volume of aqueous solution.(2)Iron oxide-graphene-silicon dioxide(G-Fe3O4-SiO2)nanocomposites for the adsorption of methyl red(MR).In this study,iron oxide-graphene-silicon dioxide(G-Fe3O4-SiO2)nanocomposites were fabricated by a facile two-step approach.Firstly,the magnetic graphene(G-Fe3O4)was prepared,secondly,a layer of mesoporous silicon oxide was deposited on the surface of the G-Fe3O4 and the G-Fe3O4-SiO2 nanocomposites were obtained.The G-Fe3O4-SiO2 nanocomposites were further applied as adsorbents for the adsorption of methyl red(MR).Effect of solution pH,adsorbent amount,adsorption time and temperature on the removal of MR were investigated.The results showed adsorption of MR onto the G-Fe3O4-SiO2 is favorable at acid conditions,the adsorption kinetics followed the pseudo-second kinetic model and the adsorption isotherms are better described by the Langmuir model.The excellent adsorption properties of the G-Fe3O4-SiO2 toward MR indicate the G-Fe3O4-SiO2 can be novel environmentally friendly and cost-effective materials for the application in preconcentration and removal of organic dyes from large volume of aqueous solution.