Removal Of Antimony(V) By Adsorption Of Iron-modified Attapulgite Adsorbent

China has the word’s largest of antimony.As Sb mining and smelting processes,large quantities of Sb have been released resulting in serious Sb contamination of the local environments and threat to human health.To find new environment materials to adsorb Sb(Ⅴ) which are of high adsorption efficiency and suitable for practical application,the development of high effective iron-coated adsorbent is the hot topic of research.The new composite material are prepared by iron-coated attapulgite,and then paramenters affecting the adsorotion effciencies including solution pH value,initial Sb(V)concentration,contact time,competing ion and ionic strength were investigated.The physical and chemical properties were characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM) and energy spectrum(EDX).The mechanism of the adsorption of Sb(V) by Fourier transform infrared spectrometer(FTIR) and X-ray photoelevtron spectroscopy(XPS).The results showed that iron-modefied attapulgite had apparent pore structure and existence of iron oxide hydroxide(FeOOH).The reaction equilibrium required15 h.Kinetics studies show that the Sb(V) adsorption kinetics over the adsorbent is well-described by the pseudo-second-order and pseudo-first-order kinetic model, but the pseudo-second-order is more better than that of pseudo-first-order kinetic model. Results indicated that in the pH range from 2-9, decreasing solution pH enhance Sb(V) removal efficiency of both composites. Increasing solution initial Sb(V) concentration from5mg/L to 80mg/L improved the uptake of Sb(V). The equilibrium adsorption data can be fitted to the Freundlich adsorption isotherm when 1/n value between 0.1-0.5,which means that the adsorption in solution can essily occur. Competitive ions of NO3-,Cl-,SO42- had little effects on the adsorptive efficiency and ionic strength posed more positive influence was observed for iron-modified attapulgite.Respectively using 0.1mol/L HCl,NaOH,NaCl and deionized water for adsorption desorption results show that the NaOH recycle must be best. Adsorptivity ofiron-modified attapulgite could be recovered by 65% when using 0.1mol/L NaOH to regenerate,and the reuse three time had drop on the recovered iron-modified attapulgite adsorption capacity.The adsorption Sb(V) mechanism was subsequently probed by FTIR,XPS charge anakysis.FTIR results indicate that peak shift of Fe-O band.The Fe-OH band was a little change in the adsorption of Sb.XPS results indicates that iron which tended to accept electrons.