Fe(Ⅵ)的制备及其分解动力学研究

Preparation and Decomposition Kinetics of Ferrate(Ⅵ) Compound

以次氯酸钠、氢氧化钠、聚合硫酸铁为原料,制备了Fe(Ⅵ)溶液,并研究了8 mol/L NaOH溶液中Fe(Ⅵ)的分解动力学,建立了分解动力学模型.通过正交实验,研究了物料比、反应温度、反应时间对Fe(Ⅵ)溶液浓度的影响,得到最适宜的工艺条件为:n(NaClO)∶n(Fe2(SO4)3)=3.4∶1,n(NaOH)∶n(Fe2(SO4)3)=26∶1,反应温度35℃,反应时间50 min.此条件下,Fe(Ⅵ)溶液浓度为0.112 2 mol/L.该分解反应为一级反应,分解活化能是51.71 kJ/mol,分解反应速率方程r=3.228×107exp(-6220/T)cFe(Ⅵ),并对其进行了验证,证实了该模型是可靠的.

Ferrate（Ⅵ）solution was prepared with sodium hypochlorite,sodium hydroxide and polymeric ferric sulfate as raw materials. Decomposition kinetics of Ferrate（Ⅵ）was studied in the 8 mol/L NaO H solution,and the kinetics model was established. Through the orthogonal experiment,effects of molar ration of reactants,the reaction temperature and reaction time on the concentration of Fe（Ⅵ）solution were studied. The optimal reaction conditions were 3.4∶1 of the molar ratio of sodium hypochlorite to polymeric ferric sulfate,26∶1 of the molar ratio of sodium hydroxide to polymeric ferric sulfate at 35 ℃ for 50 min. Under these conditions,the concentration of Fe（Ⅵ）solution was 0.112 2 mol/L. The experimental results showed that the decomposition reaction rate of Fe（VI）was first order reaction. The activation energy was determined to be 51.71 k J/mol. The equation of decomposition reaction rate can be described as：r=3.228×10^7exp（-6220/T）c Fe（Ⅵ）. The kinetics model was proved to be valid through experimental verification.