As（V）在金红石TiO2颗粒表面吸附特性及机理

通过静态动力学和热力学吸附实验，研究了温度、共存离子以及溶质的初始浓度对As（V）在金红石TiO2颗粒表面吸附的影响，探讨了As（V）在金红石TiO2颗粒表面吸附特性及机理。结果表明，在As（V）初始浓度为10mg／L，pH为7的条件下，25℃时的吸附量0．41mg／g高于30℃时的吸附量0．31mg／g，As（V）在金红石TiO，上的吸附为放热过程。CaCl2和MgCl2的添加对As（V）在金红石TiO2表面吸附起到明显的促进作用。T=25℃，Ca2＋或Mg2＋浓度为10mmol／L时，As（V）吸附量分别为0．64和0．56mg／g，Ca2＋比Mg2＋对As（V）吸附促进作用强。As（V）在金红石TiO2的吸附等温线符合Frendlich方程，Lagergren二级动力学方程能较好地描述As（V）在金红石TiO2颗粒表面吸附的动力学过程。

Adsorption characteristics and mechanism of As（V） on rutile TiO2 particles

Influences of temperature,co-existing ions and initial As（V） concentration on the adsorption of As（V） on rutile TiO2 particles were studied, and the adsorption characteristics and mechanism were discussed based on the static adsorption kinetics and thermodynamic experiments. Results showed that at an initial As （V） concentration of 10 mg/L and pH 7, an equilibrated adsorption capacity of 0.41 mg/g was achieved at 25℃ , which was obviously greater than that of 0.31 mg/g at 30℃ ,indicating an exothermic adsorption process. The ex- istence of CaCl2 and MgC12 enhanced the adsorption of As（V） on rutile TiO2. At 25℃ ,the equilibrated adsorp- tion capacities of As（V） were raised to 0.64 mg/g and 0.56 mg/g with the existence of Ca2＋ and Mg2＋ （10 mmol/L）, respectively, indicating a stronger enhancement of Ca2＋ than Mg2＋. The adsorption isotherm fitted Fre- undlich equation well, and the dynamic characteristics could be well described by the Lagergren second-order rate model.