Adsorption of Sb(III) in aqueous by MnO2-modified carbon nanotubes

A novel kind of manganese dioxide supported on multiwalled carbon nanotubes (MnO2/MWNTs) was prepared by Liquid redox method for Sb(III) removal. The MnO2 modified CNTs were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), laser particle size analyzer and N2 adsorption-desorption. The static adsorption study was carried out and parameters affecting the adsorption efficiencies including solution pH value, initial Sb(III) concentration, adsorbent dosage, contact time and temperature were investigated. The results indicate that the removal rate of Sb(III) by MnO2 modified CNTs is 97.72% under the initial Sb(III) concentration of 1.5 mg/L, adsorbents dosage of 0.5 g/L, temperature of 298 K, and pH value of 2.00, which is 51.29% higher than that of the raw CNTs. The adsorption capacity correspondingly increases from 3.01 mg/g to 6.00 mg/g. The equilibrium adsorption data can be fitted to the Freundlich adsorption isotherm. In addition, it has been found that the pH values have great impacts on the adsorption efficiency.