Sb(Ⅲ)在不同形态MnO2表面的吸附特征

Adsorption of Sb(Ⅲ) on three types of manganese dioxide

研究比较了Sb(Ⅲ)在δ态、α态和β态MnO2表面的吸附行为,深入探讨了pH、MnO2浓度、Sb(Ⅲ)初始浓度和离子强度对MnO2吸附Sb(Ⅲ)的影响。结果表明,δ态、α态MnO2对Sb(Ⅲ)的吸附等温线较好地符合Langmuir吸附等温式,β态MnO2对Sb(Ⅲ)的吸附等温线较好地符合Freundlich吸附等温式;Sb(Ⅲ)在δ态、α态MnO2表面的吸附速率较快,吸附过程符合一级反应动力学曲线,而在β态MnO2表面的吸附速率较慢,吸附过程符合二级反应动力学曲线;pH对3种形态MnO2的吸附活性影响很大,适当的MnO2浓度有利于对Sb(Ⅲ)的吸附,离子强度对MnO2的吸附活性影响不大。

Series of adsorption capacity and rate experiments were performed to study the adsorption of Sb（ Ⅲ） on three types of MnO2 （birnessite, cryptomelane and pyrolusite） and to determine the effects of pH, MnO2 dose, initial concentration of Sb（Ⅲ） and ionic strength on the adsorption rates. The adsorption capacity and/or the adsorption rate was enhanced at a lower pH, an optimal concentration of MnO2 to Sb（Ⅲ ）. Ionic strength was affected a little. The adsorptive capacity and rate data of birnessite and cryptomelane were well represented by the Langmuir adsorption isotherm and the first-order reaction rate models, respectively, while the same data of pyrolusite were well represented by the Freundlich adsorption isotherm and the second order reaction rate models.