铁锰复合氧化物吸附去除五价锑性能研究

对比研究了铁锰复合氧化物(FMBO)、羟基氧化铁(FeOOH)和二氧化锰(MnO₂)吸附去除五价锑(Sb(V))的性能.结果表明FMBO对Sb(V)具有很好的吸附性能,在pH=5.0的条件下,最大吸附容量达到1.05 mmol·g^-1,略高于FeOOH (0.82 mmol·g^-1)及远高于MnO₂ (0.43 mmol·g^-1);采用Freundlich模型可以很好地描述Sb(V)在FMBO的吸附行为(R² = 0.98).就吸附动力学而言,假二级动力学可很好地描述Sb(V)在FMBO (R² = 0.93)和MnO₂表面的吸附过程(R² = 0.96),而Sb(V)在FeOOH表面的吸附过程可用Elovich模型拟合 (R² = 0.94).Sb(V)的吸附量随着pH值的升高而降低;磷酸盐显著抑制了Sb(V)的吸附,而硫酸盐和碳酸盐影响不大.提高体系离子强度可促进Sb(V)在FMBO表面的吸附,推断Sb(V)在FMBO表面形成内层络合物后被吸附去除.

The adsorption behaviors of Fe-Mn binary oxide towards Sb(V)

The adsorption characteristics of antimonate (Sb(V)) polluted water by Fe-Mn binary oxide (FMBO) was studied and compared with FeOOH and MnO₂. The results indicated FMBO had strong adsorption ability to Sb(V) and the maximum adsorption capacity at pH 5.0 was 1.05 mmol·g^-1, which was higher than FeOOH (0.82 mmol·g^-1) and MnO₂ (0.43 mmol·g^-1). The Freundlich model best described the adsorption behavior of Sb(V) by FMBO (R² = 0.98). The Pseudo-second-order model was able to describe the adsorption kinetics of Sb(V) onto FMBO (R² = 0.93) and MnO₂ (R² = 0.96), while the Elovich model fitted best for the adsorption process of Sb(V) onto FeOOH (R² = 0.94). Sb(V) removal by FMBO was evidently dependent on pH with the greatest adsorption occurring under acidic conditions and decreased with increase in solution pH. With the exception of phosphate, normally present ions such as carbonate and sulfate had no obvious side effect on antimonate adsorption by FMBO. Sb(V) removal was promoted under higher ion strength conditions indicating that the Sb(V) removal was achieved by the formation of inner-sphere surface complexes at the water/oxide interface on FMBO.