物理化学学报 >> 1993, Vol. 9 >> Issue (06): 728-734.doi: 10.3866/PKU.WHXB19930603

研究论文 上一篇    下一篇

EDTA对均匀胶体粒子形成的影响

张玉亭; 戴仲善   

  1. 天津纺织工学院纺化系,天津 300160
  • 收稿日期:1992-03-06 修回日期:1992-06-15 发布日期:1993-12-15
  • 通讯作者: 张玉亭

The Effect of edta on the Formation of Uniform Particles

Zhang Yu-Ting; Dai Zhong-Shan   

  1. Tianjin College of Textili Technology, Tianjin 300160
  • Received:1992-03-06 Revised:1992-06-15 Published:1993-12-15
  • Contact: Zhang Yu-Ting

摘要: 特殊阴离子是决定金属盐升温水解制备均匀胶体粒子形态的重要因素之一. EDTA的存在强烈影响三价铁盐水解产物-均匀α-Fe_2O_3和β-FeOOH胶体粒子的形态. 其影响机理是EDTA在成长中的微粒子上络合吸附和溶液中的EDTA与Fe~(3+)离子间络合反应的复合结果. 前者趋于形成较大的聚合粒子; 后者趋于形成较小粒子. 进而, 凡是能够改变EDTA络合吸附状态和吸附量的. 存在于陈化液中的一切其它阴离子均会改变EDTA的作用程度.

关键词: 吸附, 络合, 聚集, 临界过饱和度, 水解

Abstract: The morphology of the precipitates of ferric hydrous oxides formed by forced hydrolysis of acidic ferric salts solutions at elevated temperature is strongly affected by the addition of EDTA to such system before aging. At lower content of EDTA, the sizes of the particles formed increase with EDTA until certain value which corresponds to point B in the typical Langmuir-type adsorption isotherm of EDTA on growing nuclei or tiny particles. The opposite phenomena have been observed at higher EDTA concentrations. These are due to the formation of ferric-DETA complex, which restricts the hydrolysis of free ferric ions and therefore the growth of crystals. In addition, any factor, e.g. anions presented in the aging solution, which will affect the adsorption of EDTA on growing nuclei or the complexing of EDTA with ferric ions might influence the extent of the effect of EDTA.

Key words: Adsorption, Complex, Coagulation, Critical supersaturation, Hydrolysis