Study On The Controllable Microfluidic Production And Adsorption Performance Of Graphene-based Microspheres

Graphene has attracted much attention for its especial structure and properties.Due to one-atom thickness,graphene has high mechanical strength and large theoretical specific surface area.Graphene and its derivatives have the advantage to be adsorbents.Microfluidics is a novel technology in the field of synthesis.Compared with the traditional method,microfluidic technology has the advantage in formation of material with controllable size and morphology.Therefore,in this study,graphene-based composite microspheres were prepared by microfluidic method.What’s more,the adsorption performance was explored.The main research contents are as follows:（1）Firstly,the microfluidic device was constructed.And the three dimensional（3D）graphene microspheres were prepare successfully.It is worth noting that the size of the microspheres can be controlled by adjusting the synthesis conditions.In order to learn the properties of graphene microspheres deeply,some characterization were conducted,such as scanning electron microscopy（SEM）,X-ray diffraction（XRD）,Fourier transform infrared spectroscopy（FTIR）and X-ray photoelectron spectra（XPS）.Besides,the adsorption properties of graphene microspheres were also studied,the results indicated that the controllable preparation of graphene microspheres was successfully achieved by microfluidic method.In addition,a high removal efficiency was achieved for different types of pollutants.（2）A series of composite microspheres were designated by microfluidic method.These microspheres were characterized by FTIR and Zeta potential.The adsorption properties of the composite microspheres for different dyes（cationic dye methylene blue and anionic dye methyl orange）were investigated.The adsorption kinetics,adsorption isotherms,influencing factors and adsorption mechanisms were also studied.It was shown that the composite adsorbent had high effective adsorption performance for dyes.Moreover,with the change of content of CS and pH value in the system,composite microspheres presented the selective adsorption and separation ability.（3）On the basis of the material and synthetic method,MnO₂-graphene oxide-based micromotors as adsorbent were synthesized successfully.The obtained micromotors were characterized by SEM,XRD and FTIR.The effect of hydrogen peroxide concentration on the motion and the removal efficiency for MB was also explored.The results showed that almost all the MB（99.81%）was removed by self-propelled micromotors.An increase in velocity of micromotors was exhibited as H₂O₂ concentration increases,as a result,a faster adsorption rate and the shorter time to reach adsorption equilibrium could be realized.Overall,three kind of graphene-based microspheres were synthesized by microfluidic technology and they have excellent properties for removal of contaminants from aqueous solutions,which will provide theoretical support for wastewater treatment.