摘要
The adsorption potential of FMBO, FeOOH, MnO2 for the removal of Cd^2＋, Cu^2＋ and Pb^2＋ in aqueous systems was investigated in this study. Comparing to FMBO and FeOOH, MnO2 offered a much higher removal capacity towards the three metal ions. The maximal adsorption capacity of MnO2 for Cd^2＋, Cu^2＋ and Pb^2＋ were 1.23, 2.25 and 2.60 mmol· g^-1, respectively. And that for FMBO were 0.37, 1.13, and 1.18mmol·g^-1 and for FeOOH were 0.11, 0.86 and 0.48 mmol·g^-1, respectively. The adsorption behaviors of the three metal ions on the three adsorbents were all significantly affected by pH values and heavy metal removal efficiency increased with pH increased. The Langmuir and Freundlieh adsorption models were used to describe the adsorption equilibrium of the three metal ions onto the three adsorbents. Results showed that the adsorption equilibrium data fitted well to Langmuir isotherm and this indicated that adsorption of metal ions occurred on the three metal oxides adsorbents limited to the formation of a monolayer. More negative charged of MnOa surface than that of FMBO and FeOOH could be ascribed by lower pHiep of MnO2 than that of FMBO and FeOOH and this could contribute to more binding sites on MnO2 surface than that of FMBO and FeOOH. The higher metal ions uptake by MnO2 than FMBO and FeOOH could be well explained by the surface charge mechanism.
The adsorption potential of FMBO, FeOOH, MnO2 for the removal of Cd^2＋, Cu^2＋ and Pb^2＋ in aqueous systems was investigated in this study. Comparing to FMBO and FeOOH, MnO2 offered a much higher removal capacity towards the three metal ions. The maximal adsorption capacity of MnO2 for Cd^2＋, Cu^2＋ and Pb^2＋ were 1.23, 2.25 and 2.60 mmol· g^-1, respectively. And that for FMBO were 0.37, 1.13, and 1.18mmol·g^-1 and for FeOOH were 0.11, 0.86 and 0.48 mmol·g^-1, respectively. The adsorption behaviors of the three metal ions on the three adsorbents were all significantly affected by pH values and heavy metal removal efficiency increased with pH increased. The Langmuir and Freundlieh adsorption models were used to describe the adsorption equilibrium of the three metal ions onto the three adsorbents. Results showed that the adsorption equilibrium data fitted well to Langmuir isotherm and this indicated that adsorption of metal ions occurred on the three metal oxides adsorbents limited to the formation of a monolayer. More negative charged of MnOa surface than that of FMBO and FeOOH could be ascribed by lower pHiep of MnO2 than that of FMBO and FeOOH and this could contribute to more binding sites on MnO2 surface than that of FMBO and FeOOH. The higher metal ions uptake by MnO2 than FMBO and FeOOH could be well explained by the surface charge mechanism.
