Preparation Of Mganetic Chrysotile Nanotubes And Their Adsorption Of Heavy Metals Ions

In this work, magnetic chrysotile nanotubes were prepared by doping methods. Theresearch is to conquer several shortages existing in natural chrysotile and increase theefficient of separated from solution by magnet. The morphology structure and magneticproperties of doped chrysotile nanotubes were primarily studied. After that, theadsorption properties of Pb(II), Cd(II) and Cr(III) on doped chrysotile nanotubes wereinvestigated by batch method and the adsorption mechanism was evaluated.The characterization results showed that the prepared samples have hollow structureand preferable saturation magnetization. Doped chrysotile nanotubes could be quicklyseparated from aqueous solutions by a permanent magnet, the result is similar withcoprecipitated chrysotile nanotubes.According to the experimental results, pH and ionic strength affected the adsorptionof Pb(II), Cd(II) and Cr(III) on doped chrysotile nanotubes obviously. The adsorptionkinetics and isotherms of doped chrysotile nanotubes for Pb(II), Cd(II) and Cr(III) arefitted well by the pseudo-second-order model and Langmuir model, respectively. Theadsorption process of Pb(II), Cd(II) and Cr(III) on doped chrysotile nanotubes isspontaneous and endothermic. At low pH, the adsorption mechanism of Pb(II), Cd(II)and Cr(III) could be explained as ion exchange and outer-sphere surface complexation,whereas surface precipitation was the main adsorption mechanism at high pH. Inaddition, comparing with other adsorbents, the prepared doped chrysotile nanotubesshowed better adsorption capacity and excellent regeneration property, and it could beeasily separated from aqueous solutions using a magnetic separation method.