Preparation And Modification Of Nano-Fe₃O₄/MnO₂@graphene And Its Adsorption Of Pb(?)

In recent years,with the rapid development of society and industry,the problem of heavy metal pollution in water bodies has become increasingly serious.Among them,the heavy metal Pb?II?pollution has become a typical problem in heavy metal pollution.Graphene nanomaterials have been attracting more and more attention from many researchers for their excellent physical and chemical properties.In this paper,the heavy metal Pb?II?was selected as the target contaminant.The magnetic nano-Fe₃O₄@RGO,nano-MnO₂@RGO and nano-Fe₃O₄/MnO₂@RGO adsorbents were prepared by hydrothermal synthesis and coprecipitation.The effects of adsorbent dosage,solution pH,initial concentration and reaction temperature on the adsorption of Pb?II?by graphene composite adsorbents were investigated by static adsorption experiments.Scanning electron microscopy?SEM?,magnetometer?VSM?,specific surface area?BET?,X-ray diffraction?XRD?and X-ray photoelectron spectroscopy?XPS?were used to characterize the chemical structure and micromorphology of the three adsorbent materials,combined with adsorption isotherms and adsorption kinetics,the mechanism of adsorption of Pb?II?by three graphene composite adsorbents was investigated.The main findings are as follows:Through the performance and structural characterization of SEM,VSM,BET,XRD and XPS,it can be found that the preparation of magnetic nano-Fe₃O₄@RGO,nano-MnO₂@RGO and nano-Fe₃O₄/MnO₂@RGO have been more successfully,which was in line with the experimentally expected target.Batch static adsorption experiments using nano-Fe₃O₄@RGO,nano-MnO₂@RGO,nano-Fe₃O₄/MnO₂@RGO to adsorb Pb?II?results showed that with the increase of adsorbent dosage,the removal efficiency of Pb?II?was increased,and indicated the adsorption of Pb?II?in the aqueous solution by these three adsorbents is a rapid adsorption process.The removal of Pb?II?in the solution under acidic conditions is always kept at a low level.The adsorption effect of the adsorbent on Pb?II?increases with increasing temperature.The adsorption of Pb?II?by magnetic nano-Fe₃O₄@RGO,nano-MnO₂@RGO and nano-Fe₃O₄/MnO₂@RGO can be described by Langmiur isotherm model and pseudo second order kinetic equation.Adsorption is monolayer adsorption.The saturated adsorption capacities of the three adsorbents were 60.18,265.15 and 263.25 mg/g,respectively,and the adsorption process was mainly chemical adsorption.The three prepared adsorbents still showed good adsorption performance after repeated adsorption desorption cycles,which indicates that they have excellent regeneration value.These results showed that magnetic nano-Fe₃O₄@RGO,nano-MnO₂@RGO and nano-Fe₃O₄/MnO₂@RGO could be considered as a potential and effective adsorbent for the removal of Pb?II?from aqueous solution.