甲基橙催化光度法测定痕量铬(Ⅵ)  

Photometric Determination of Trace Amount of Chromium(Ⅳ)Based on Its Catalytic Effect on Decolorization of Methyl Orange

作　　者：宋仲容[1] 何家洪[1,2] 高志强[1] 徐强[1] 

机构地区：[1]重庆文理学院化学与环境科学系,永川402168 [2]重庆大学化学化工学院,重庆400044

出　　处：《理化检验（化学分册）》2009年第11期1299-1301,共3页Physical Testing and Chemical Analysis(Part B:Chemical Analysis)

基　　金：重庆市教育委员会资助项目(KJ051201);重庆文理学院重点科研项目(Z2006HH01)

摘　　要：在0.05 mol·L^(-1)硫酸介质中,90℃水浴加热9 min时,痕量铬(Ⅵ)对过氧化氢氧化甲基橙褪色反应有显著的催化作用,研究了该催化褪色反应的最佳条件,提出了催化光度法测定痕量铬(Ⅵ)的方法。该反应表观活化能为25.73 kJ·mol^(-1),铬(Ⅵ)质量浓度在72μg·L^(-1)以内,与△A呈线性关系,检出限(3s/k)为0.058 mg·L^(-1)。用于工业废水和湖水等3个样品中铬(Ⅵ)量的测定,测定结果与二苯碳酰二肼标准法测得的结果相符。In a 0. 05 mol · L^-1 H2SO4 medium, the oxidative color-fading reaction of methyl orange with hydrogen peroxide was remarkably catalyzed by the presence of trace amount of Cr （ Ⅵ ）, when heated in a water bath at 90 ℃ for 9 min. Under the optimum condition, linear relationship between the values of decrease in absorbance （△A） and concentration of Cr（Ⅵ） was obtained in the range within 72 μg · L^-1. The apparent activation energy of the above mentioned catalytic reaction was found to be 25. 73 kJ · mol^-1. Detection limit （3s/k） of the reaction found was 0. 058 mg ·L^-1. Based on these facts, a photometric method for determination of trace amount of Cr（Ⅵ） in industrial waste water and lake water was proposed. In analyzing 3 water samples by this method, results of Cr（Ⅵ） found were in consistency with the results found by the DPC photometric method.

关 键 词：催化光度法 甲基橙 铬(Ⅵ 过氧化氢 工业废水 

分 类 号：O657.32[理学—分析化学]