Synthesis Of γ-Fe₂O₃ Nanoparticles And Their Adsorptive Properties

In recent years, increasing amount of wastewater containing heavy metals and organic dyes has been released into the environment, which caused great threat for human health. Adsorption method is believed to be an ideal method for the treatment of wastewater owing to its large removal ability, less expensive, economical, easy operation. Magneticγ-Fe2O3 nanoparticles have a strong adsorption ability for heavy metals,organic dyes in wastewater, and they could easily be separated from treated water with magnetic separation technology.In this work, γ-Fe2O3 nanoparticles were synthesized and its adsorption capacity for several pollutants in industrial wastewater was investigated, so as to provide a more reliable innovative data for the treatment of wastewater.Firstly, water dispersible γ-Fe2O3 nanoparticles were successfully prepared by solvothermal methed-oxidation method, with Fe-ruea complex and triethylene glycol as raw materials. The product was characterized by means of X-ray powder diffraction(XRD), differential thermogravimetric analysis(DTA-TG), transmission electron microscope(TEM), N2 adsorption-desorption(BET), pore size distribution(BJH) and magnetic measurements(VSM). The results show that the pure γ-Fe2O3 nanoparticles with an average particle size of 7 nm can be obtained by this method. The synthesized γ-Fe2O3 nanoparticles possess superparamagnetic properties with a high saturation magnetization at room temperature and good dispersibility in water. The maximum saturation magnetization and the maximum specific surface area of theγ-Fe2O3 nanoparticles are measured to be 52.4 emu/g and 89.2 m2/g,respectively. The maximum adsorption capacities of the water dispersibleγ-Fe2O3 for Cr(VI), congo red and methyl orange reaches to 25.9 mg/g,53.9 mg/g and 182.5 mg/g, respectively.Secondly, ultrasmall γ-Fe2O3 nanoparticles were prepared by sol-gel method, and they were characterized by XRD、TEM、IR、BET and VSM.At the same time, the adsorption capacity of the ultrasmall nanoparticles for methyl blue was also investigated. The maximum adsorption capacity for methyl blue is 169.2 mg/g.