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化学学报
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化学学报 ›› 2007, Vol. 65 ›› Issue (13): 1191-1196.    下一篇

研究论文

东北草甸棕壤的零电荷点和界面酸-碱反应特征平衡常数

徐洁1, 侯万国*,1,2, 周维芝1, 台培东3, 王文兴1   

  1. (1山东大学环境研究院 济南 250100)
    (2山东大学胶体与界面化学教育部重点实验室 济南 250100)
    (3中国科学院沈阳应用生态研究所 沈阳 110016)
  • 投稿日期:2006-11-21 修回日期:2007-02-02 发布日期:2007-07-14
  • 通讯作者: 侯万国

Point of Zero Charge and Intrinsic Surface Reaction Equilibrium Constants of Meadow Brown Soil in Northeast of China

XU Jie1; HOU Wan-Guo*,1,2; ZHOU Wei-Zhi1; TAI Pei-Dong3; WANG Wen-Xing1   

  1. (1 Environment Research Institute, Shandong University, Jinan 250100)
    (2 Key Laboratory for Colloid & Interface Chemistry of Education Ministry, Shan-dong University, Jinan 250100)
    (3 Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016)
  • Received:2006-11-21 Revised:2007-02-02 Published:2007-07-14
  • Contact: HOU Wan-Guo

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被引次数

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分别采用电势滴定(Potentiometric titration)法, 质量滴定(Mass titration)法和惰性电解质滴定(Inert electrolyte titration)法测定了荷结构负电荷的东北草甸棕壤的零净电荷点(PZNC), 研究表明荷结构负电荷的土壤依然存在与电解质浓度无关的零净电荷点, 三种方法的实验结果分别为2.9, 5.0和3.3. 相比较而言, 电势滴定法和惰性电解质滴定法的结果相近, 而质量滴定法的结果偏高. 对文献中推算表面质子活性位密度(Ns)的方法进行了改进, 得到东北草甸棕壤样品的Ns为2.5 mmol•g－1. 根据实验测定的pHPZNC, Ns和结构电荷密度(σst)值直接计算得出东北草甸棕壤样品的界面反应特征平衡常数即1-pK模型中的pK, 2-pK模型中pKa1int和pKa2int, 分别为3.37, 2.42和4.32, 与文献报道的沉积物和蒙脱土的值相吻合.

关键词: 黏土, 零电荷点, 界面反应模型, 东北草甸棕壤

The point of zero net charge (PZNC) for the meadow brown soil in northeast of China with structural negative charges was measured by three methods: potentiometric titration, mass titration and inert electrolyte titration, showing that for the meadow brown soil which possesses structural negative charges, a PZNC independent of electrolyte concentration exists, and the values of pHPZNC obtained by the above three methods are 2.9, 5.0 and 3.3, respectively. It was found that the values of pHPZNC determined by potentiometric titration and inert electrolyte titration were very close while that determined by mass titration was relatively high. The estimating method of the total density of surface proton-active sites (Ns) in literatures was improved to obtain the Ns value of the meadow brown soil in northeast of China, which is 2.5 mmol• g－1. According to the values of pHPZNC, Ns and structural negative charge density (σst) measured, the intrinsic surface reaction equilibrium constants, pK of 1-pK model, pKa1int and pKa2int of 2-pK model, were directly calculated to be 3.37, 2.42 and 4.32, respectively, for the meadow brown soil in northeast of China.

Key words: clay, point of zero charge, interface reaction model, meadow brown soil in northeast of China