Preparation Of Fe-Loaded Activated Ca Rbon And Itsadsorption Property To U Ranyl Ion In Aqueous Solution

The Uranium containing waste water,a byproduct of mining and extraction processes,could rise background radiation level around uranium ores and cause genic mutation,which endangers human beings and social development.Metal iron has been recognized as a potential material in environmental pollution remediation due to its relatively higher reaction activity.However,metal iron is readily oxidized and polymerized,a major flaw declined in applications.Recently,Fe loaded Active Carbon(Fe-AC)is found to be an effective packing method to make up metal iron defect.Therefore,it is of vital importance to develop a process of producing an efficient and low-cost Fe-AC.In this paper,three methods are employed to produce Fe-AC,i.e.,Liquid Reduction method(LR),Carbonthermal Treatment method(CT),Incipient Wetness method(IW),respectively.The corresponding Fe-ACs are then analyzed by Scanning Electron Microscope(SEM),X-ray diffraction(XRD),Specific Surface Area&Pore Size(SSA&PZ),X-ray photoelectron spectroscopy(XPS)and Fourier Transform Infra-Red(FTIR).Factors that would affect efficiency of U(VI)removal are studied by the virtue of static test method.The U(VI)removal mechanism of respective method is drawn from adsorption kinetics,isotherms and thermodynamics analysis.The context of this paper goes as follows:(1)U(VI)removal by Fe-AC-LRData suggests,iron uniformly adheres to pores of active carbon in the form of spherical particles.the surface of these iron particles then turn into new phase after reaction with U(VI).The maximized condition for U(VI)adsorption is: AC diameter(d)?75 ?m,mass ratio of FeSO4·7H2O to AC(mFe/mAC)1.25 g/1.00 g,Fe-AC-LR mass(m)0.80 g/L,duration(t)1.00 h,pH=5.00.In contrast to the weak influence of Co and temperature(T)on adsorption process,humic acid and ionic strength affect this process to large extent.Pseudo-2ndorder kinetic model,Freundlich and Redlich-Pertersonadsorptionisothermmodel are in good agreement with the adsorption process.(2)U(VI)removal by Fe-AC-CTData suggests,iron particles are uniformly distributed on the surface of active carbon with good crystallinity and then oxidized as petal-like Fe2O3 after adsorption.A corresponding maximized condition of adsorption is: d?75 ?m,mFe/mAC=5.00 g/1.00 g,m=2.00 g/L,Co=125 mg/L,t=72.00 h,pH=5.00,T=50.0 oC.humic acid and ionic strength accelerate U(VI)adsorption process.U(VI)adsorption by Fe-AC-CT is qualified as pseudo-first order kinetic model?pseudo-2nd order kinetic model and in line with Langmuir and Redlich-Perterson isothermmodel.(3)U(VI)removal by Fe-AC-IWData suggests,metal iron is sparsely loaded on the surface of active carbon with a core-crust structure.The maximized adsorption condition is: d?75 ?m,mFe/mAC=5.00 g/1.00 g,m=1.00 g/L,t=72.00 h,pH=5.00,T=50.0 oC.humic acid and ionic strength play a positive role in this process.U(VI)adsorption by Fe-AC-IW is consistent with pseudo-2nd order kinetic model?Langmuir and Redlich-Perterson.