Study On Removal Of As(?) From Wastewater By Iron-carbon Composite Material Mingled With Rare Earth

In this paper,a new spherulitic material called iron-carbon composite material mingled with rare earth was made by ceria,iron powder and activated carbon to remove As(?)from wastewater,and got great achievements.Determined the best preparation process by single factor experiments and orthogonal experiments,simultaneously characterized the material.Also researched effect of the material treat different characters wastewater,fitting the adsorption process with thermodynamics and kinetics.Finally,through the desoiption experiments to study the regenerative properties of the material.The results showed:(1)During the preparation process of the iron-carbon composite material mingled with rare earth,the various factors from most to least influence was:roast temperature,iron-carbon mass ratio,mass fraction of ceria.The best scheme was:iron-carbon mass ratio 1:1,mass fraction of ceria 3%,roast temperature 600 ?.In these conditions,the removal efficiency of the As(?)from wastewater could be 94.87%.(2)The characterization results:The X-ray diffraction showed the material had great crystallinity,and changed the roast temperature couldn't change the formation of crystals,and there were no new crystal after the adsorption,the As(?)adsorbed by the material didn't enter into the inside lattice.The Fourier Transform Infrared Spectrometer showed that in the adsorption process,the carbon-oxygen bonding played a major role.The Scanning Electron Microscope showed that ceria could increase the surface area of the material.(3)Researched effect of the material treat different characters wastewater,the results showed,when the dosages was 0.75 grams,the initial As(?)concentration was 10 mg/L,the initial pH was 6,after two hours the removal efficiency of As(?)could be 99.04%.(4)Analyzed the adsorption process with kinetics,the results showed:under the initial concentration of 10 mg/L?20 mg/L?30 mg/L,the saturation adsorption capacities of the material could be 1.255mg/g?2.311 mg/g?3.890 mg/g.The adsorption process conformed the Lagergren first order kinetics and particle diffusion dynamics.(5)Analyzed the adsorption process with thermodynamics under the temperature of 303K?313K?323K,the results showed:the adsorption process conformed the Langmuir isotherm model best,the adsorption sites of the material distributed uniform in the surface,but non-uniform distribution was more.The thermodynamic parameter showed that the adsorption process was an exothermic process,and the rise of temperature was no advantage of the reaction.(6)The desorption experiments with the material after adsorption showed that the 0.8mol/L sodium hydroxide solution has great desorption efficiency to the material,the desorption rate could be 96.36%.The material has great renewability.