[Effects of pH and Complexing Agents on Sb(Ⅴ) Adsorption onto Birnessite and Ferrihydrite Surface].

Effects of pH and complexing agents on Sb (Ⅴ) adsorption onto birnessite and ferrihydrite surface were investigated.The results indicated that birnessite and ferrihydrite had strong ability to adsorb Sb (Ⅴ).The removal efficiencies of Sb (Ⅴ) by birnessite and ferrihydrite were dependent on the initial pH in solution.The removal efficiency of Sb (Ⅴ) increased with the decrease of solution pH.At pH 5.0,the removal efficiencies,adsorption rate and adsorption capacity were better than those at pH 7.0 or 9.0.The adsorption process of Sb (Ⅴ) on birnessite and ferrihydrite could be well described by the pseudo-second-order model.The Langmuir model best described the adsorption behavior of Sb (Ⅴ) by birnessite and ferrihydrite at pH 5.0.The presence of citric acid or EDTA had significant effect on Sb (Ⅴ) adsorption onto birnessite and ferrihydrite.