Preparation And Adsorption Performance Of Graphene Oxide/molecular Sieve Composite Materials For Rhodamine B Solution

Dyestuff wastewater treatment is one of the most difficult industrial wastewaters to treat.The adsorption technology is considered as the most promising method for purifying water with its high efficiency and low energy consumption in the process of removing dye wastewater.Molecular sieve is widely used as adsorbent because of its good adsorption selectivity,stable structure,easy regeneration and low cost,green environmental protection and so on.But the single molecular sieve adsorption of organic matter is also low,in recent years,molecular sieve composite adsorbent material began to enter our field of vision.In this paper,new composite materials were prepared for the adsorption of dye wastewater.By using the advantages of graphene and molecular sieves on the adsorption properties of organic compounds,the composites with different contents of graphene oxide were prepared by means of hydrothermal treatment by using oxidized graphene and molecular sieve surface rich active groups.The synergistic effect between the two compounds on the adsorption properties of contaminants were studied.The surface of Silicalite-1,Beta and Y molecular sieves were modified with graphene oxide(GO)solution to prepare graphene oxide/molecular sieve composites in this paper.The samples were characterized by X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FI-IR),field emission scanning electron microscopy(FE-SEM),Raman spectroscopy(UV-Vis),X-ray photoelectron energy(XPS),specific surface area and pore size(BET)were used to characterize the structure of the composites.The adsorption performance of three graphene oxide/molecular sieve composites was studied by using Rhodamine B in aqueous solution as adsorption object.The effects of(1)The amount of graphene oxide on the morphology and structure of the composites.(2)The adsorption time,pH,temperature,Rhodamine B initial concentration on the adsorption effect.(3)The effect of repeated use of composite materials on the adsorption performance were investigated.The experimental results show that:(1)The graphene oxide/molecular sieve composites are prepared successfully,and the specific surface area of the composites decreases with the increase of the content of graphene oxide.(2)Adsorption of rhodamine B on the three molecular sieves and their composites reached the equilibrium state at 60 min.Adsorption was favored under acidic conditions and the adsorption capacity was the best at pH = 3.Compared with molecular sieves,the sorption capacity of the molecular sieve composites is obviously improved.(3)The adsorption isotherms of the three molecular sieves and their composites all accorded with the Langmuir adsorption model.The maximum adsorption capacity of Silicalite-1,Beta,Y molecular sieves and their composites GS-3(with 10 wt.%of GO),GB-3(with 6 wt.%of GO),GY-3(with 10 wt.%of GO)calculated by the Langmuir model were 12.80 mg/g,27.97 mg/g?9.50 mg/g and 51.55 mg/g?64.47 mg/g?39.64 mg/g,respectively.(4)The molecular sieves and their composites can be reused,but with the used time of adsorbents increase,the adsorption efficiency will decrease gradually.The advantage of the graphene oxide/molecular sieve composites used as adsorbent for the treatment of wastewater is simple operation,low cost,large adsorption capacity and pollutants can be recycled.