高铁酸钾的制备及其对水中As(III)、Pb(II)的去除效能研究

Preparation of Potassium Ferrate and Its Effectiveness on the Removal of As(III) and Pb(II)

  • 摘要: 利用正交法得出次氯酸盐氧化法合成高铁酸钾的最佳工艺条件,以FTIR、XRD、SEM、EDS、TEM表征证实其纯度可达95%. 在砷、铅单独及复合污染的处理中比较了K2FeO4投加量、起始pH对处理效果的影响. 实验表明,当砷、铅起始质量浓度为2 mg/L,溶液pH 65,铁砷质量浓度比为16或铁铅质量浓度比为4时,沉淀后水中砷、铅质量浓度均可低于10 g/L;K2FeO4同样能有效处理砷铅复合污染,在K2FeO4投加量为24 mg/L时,对砷、铅的去除率分别为9930%和100%;与单独污染相比,低K2FeO4投加量下,砷与铅的竞争关系明显.通过结合Visual 〖JP2〗MINTEQ化学平衡模拟软件对实验机理进行分析表明:高铁酸钾通过氧化、电中和及表面络合等作用去除水中砷、铅.〖JP〗

     

    Abstract: Potassium ferrate (K2FeO4) was synthesized by hypochlorite oxidation. Orthogonal method was applied to optimize the synthesis process. The obtained K2FeO4 had a purity of 95% or higher. The synthesized K2FeO4 was used as a coagulant to remove As(III) and Pb(II) in single and bi-solute systems. Effects of K2FeO4 dosage and operating pH on the removal of As(III) and Pb(II) were studied. In the single system, results shows that at pH 65, Fe/As=16 (wt/wt) and Fe/Pb=4 (wt/wt), the residual As and Pb were less than 10 g/L. In the bi-solute system, ferrate could remove As and Pb simultaneously. When ferrate dose was 24 mg/L, the removal rates of As and Pb were 99.30% and 100%, respectively. At low ferrate dose, the competitive adsorption behavior of As(III) and Pb(II) in the bi-solute system was observed. Visual MINTEQ software was used to calculate and simulate metal speciation in solution at equilibrium aiming at elucidate the removal mechanism of As and Pb by potassium ferrate.

     

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