Dependence of the mechanism of phase transformation of Fe(III) hydroxide on pH

被引:25
作者
Liu, H
Wei, Y [1 ]
Sun, YH
Wei, W
机构
[1] Hebei Normal Univ, Coll Chem, Shijiazhuang 050016, Peoples R China
[2] Chinese Acad Sci, Inst Coal Chem, Taiyuan 030001, Peoples R China
关键词
Fe(OH)(3) gel; phase transformation; mechanism; hematite; beta-FeOOH;
D O I
10.1016/j.colsurfa.2004.10.105
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The phase transformation from Fe(OH)3 gel to alpha-Fe2O3 particles at different initial pHs at about 100degreesC was studied. The time necessary for completing the above process was determined. The results showed that the time of phase transformation from Fe(OH)(3) gel to alpha-Fe2O3 particles shortened with the increase of initial pH at pH < 4.5. In this pH range, beta-FeOOH, as an intermediate product, was obtained and hematite was formed by dissolution/reprecipitation mechanism. However, in the pH range from 4.5 to 9.0, the transformation time prolonged with increasing pH. In this pH range, no intermediate product was found. From Fe(OH)(3) gel to hematite, there are two transformation pathways. One is the dissolution/reprecipitation mechanism and the other is the solid state transformation mechanism. With the pH close to the point of zero charge (pzc) of Fe(OH)(3) gel, the later mechanism gradually predominated. (C) 2004 Elsevier B.V. All rights reserved.
引用
收藏
页码:201 / 205
页数:5
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