碱性溶液中N_2H_4还原Cr(VI)的反应动力学研究  

Study on kinetics of chromium(VI) reduction by hydrazine in the alkaline solution

作　　者：王天贵[1] 余锡孟[1] 蒋世伟[1] 

机构地区：[1]河南工业大学化学化工学院,河南郑州450001

出　　处：《化学工程师》2008年第1期11-14,共4页Chemical Engineer

摘　　要：本文研究了碱性溶液中N2H4还原Cr（Ⅵ）的反应动力学及机理。在25℃下，用NH4Cl-NH3·H2O缓冲溶液控制体系pH值为8．0～10．0，分别采用Cr（Ⅵ）和N2H4过量的方法，测定反应过程中Cr（Ⅵ）和N2H4的消耗量及其浓度随时间的变化。结果表明，N2H4还原Cr（Ⅵ）的氧化还原反应按下面方程进行：2CrO4^2-＋3N2H4＋10H^＋=2Cr^3＋＋2N2＋2NH3＋8H2O，反应对Cr（Ⅵ），N2H4和H^＋浓度均为一级，总反应为三级。The kinetics of Cr （Ⅵ） reduction by hydrazine in alkaline solution was studied. Batch experiments with excess Cr （Ⅵ） over N2H4 and excess N2H4 over Cr （Ⅵ） were undertaken under 25℃, pH =8.0 - 10. 0 controlled by NH4Cl -NH3 · H2O buffer solution. Results showed that the reaction took place as followed： 2CRO4^2- ＋ 3N2H4 ＋ 10H^＋=2Cr^3＋ ＋2N2 ＋ 2NH3 ＋ 8H2O. The overall reaction was third -order, i.e. first with respect to Cr （Ⅵ） , N2H4 and H^＋.

关 键 词：铬 水合肼 还原 动力学 

分 类 号：TQ110.1[化学工程—无机化工]