Hybrid Hematite/multi-walled Carbon Nanotube（α-Fe₂O₃/MWCNT） Nanostructures As Sorbents For Cu（Ⅱ） And Cr（Ⅵ）

Water pollution by Cu （Ⅱ） or Cr （Ⅵ）has been the focus of the study of manydomestic and foreign scholars, also a lot kinds of methods were taken to treatment andthe repairmen of the wastewater containing Cu （Ⅱ） or Cr （Ⅵ）, as well as the pollutedwater, adsorption is one of the most frequently used methods. With the integrity ofnanotechnology and the increase of people’s environmental protection awareness,nanometer materials and nanometer composite material also have began to applied inthe field of adsorption, and showed a distinct advantage.In the experiment，we prepared hematite nanoparticles and developed a novel classof hybrid nanostructures, The hybrid nanostructures were synthesized via the hydrolysisof ferric nitrate[Fe（NO3）3] in the presence of carboxylated MWCNTs,TEM、BET、Zetapotential and XRD were taken to characterize these nano-particles, Characterization ofα-Fe₂O₃/MWCNT nanostructures revealed that the amount of hematite nanoparticles are0.07and0.5g/g a-Fe₂O₃/MWCNT respectively, and the size of hematite nanoparticlesare5.9（±1.1） and8.9（±1.5） nm respectively. the amount of hematite nanoparticlesimmobilized on MWCNTs surfaces were tunable by regulating the hydrolysis quantityof [Fe（NO3）3] during synthesis,and the diameter increased with the raise of the total ironquality which deposition on the surface of MWCNTs.The adsorption of Cu（Ⅱ） and CrO₄^2-in aqueous solutions by oxidized MWCNTs、α-Fe₂O₃、 α-Fe₂O₃/MWCNT nanostructures respectively investigated in a batch-adsorption experiments. The influences of the solution pH value and the initial metalion concentration of solution towards the adsorption effect were observed. The resultsrevealed that mass normalized concentrations of adsorbed Cu（Ⅱ） and CrO₄^2-weregreatest for α-Fe₂O₃/MWCNT relative to adsorption on either MWCNTs or freelysuspended α-Fe₂O₃nanoparticles.The enhanced sorption capacity of the hybridnanostructures is due to their greater available surface area of MWCNTs-immobilizedα-Fe₂O₃when compared to extensively aggregated α-Fe₂O₃nanoparticles insuspension.differences in the pH-dependent trends of Cu（Ⅱ） and CrO₄^2-uptake onα-Fe₂O₃/MWCNT nanostructures also suggest that the immobilized α-Fe₂O₃nanoparticles exhibit unique and enhanced surface reactivity relative to their freelysuspended nanoparticle analogues.