Surface Characteristics of Magnetite in Aqueous Suspension

✍ Scribed by Zhong-Xi Sun; Fen-Wei Su; Willis Forsling; Per-Olof Samskog

• Publisher: Elsevier Science
• Year: 1998
• Tongue: English
• Weight: 653 KB
• Volume: 197
• Category: Article
• ISSN: 0021-9797
• DOI: 10.1006/jcis.1997.5239

✦ Synopsis

of magnetite surface and its behavior in water solution could Surface characteristics of magnetite at 25ЊC in aqueous suspenprovide a better understanding of the mechanisms involved sions are systematically studied. The measured specific surface in this process.

area and concentration of proton binding sites correspond well to

The surface properties of magnetite have been studied (2the calculated values. Zeta potential of magnetite in the absence 4). It was reported that magnetite surface possesses acidof multivalent cations exhibits positive values in acidic solution base properties and the pK values of magnetite surfaces are and becomes negative with increasing pH. pH pzc is about 6. In the reported to be 4.4 (pK 1 ) and 9.0 (pK 2 ), respectively (3, presence of excess cations such as Fe 2/ or Fe 3/ , specific adsorption 4). It was also reported that magnetite can transform into takes place at the surface of magnetite, which dramatically influmaghemite and release ferrous ions in acidic pH (5). The ences the value of zeta potential. The concentrations of soluble Fe ions at pH about 4.5 increase with solid concentrations of magne-correlation between magnetite-maghemite transformation tite indicating some surface-related reaction mechanisms. ᭧ 1998 and surface protonation is crucial in understanding surface-Academic Press reaction mechanisms. However, no quantitative explanation Key Words: magnetite; surface complexes; zeta potential; soluhas been reported. Due to the diversity of mineral samples, bility; surface binding site.

the surface properties could be varied under different conditions. In order to clarify the reaction mechanisms, the surface characteristics of different types of magnetite should be sys-