The surface state of hematite and its wetting characteristics

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:477

Article

Shrimali, Kaustubh¹  Jin, Jiaqi¹  Hassas, Behzad Vaziri¹  Wang, Xuming¹  Miller, Jan D.¹ 

[1] Univ Utah, Coll Mines & Earth Sci, Dept Met Engn, 135 South 1460 East,Room 412, Salt Lake City, UT 84112 USA

关键词: Hematite;    Goethite;    Atomic force microscopy;    Molecular dynamics simulation;    Hydroxylation;    Zeta potential;   

DOI  :  10.1016/j.jcis.2016.05.030

来源: Elsevier

【 摘 要 】

Apart from being a resource for iron/steel production, the iron oxide minerals, goethite and hematite, are used in the paint, cosmetics, and other industries as pigments. Surface characteristics of these minerals have been studied extensively both in resource recovery by flotation and in the preparation of colloidal dispersions. In this current research, the wetting characteristics of goethite (FeOOH) and hematite (Fe2O3) have been analyzed by means of contact angle, bubble attachment time, and Atomic Force Microscopy (AFM) measurements as well as by Molecular Dynamics Simulation (MDS). Goethite is naturally hydroxylated and wetted by water at all pH values. In contrast, the anhydrous hematite surface (001) was found to be slightly hydrophobic at natural pH values with a contact angle of about 50 degrees. At alkaline pH hydroxylation of the hematite surface occurs rapidly and the hematite becomes hydrophilic. The wetting characteristics of the hematite surface then vary between the hydrophobic anhydrous hematite and the completely hydrophilic hydroxylated hematite, similar to goethite. The hydrophobicity can be restored by heating of the hydroxylated hematite surface at 60 degrees C. The hydrophobic character of the anhydrous hematite (001) surface is confirmed by MDS which also reveals that after hydrolysis the hematite (001) surface can be wetted by water, similar to the goethite (001) surface. (C) 2016 Elsevier Inc. All rights reserved.

【 授权许可】

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