Dependence of the Heat of Immersion of Maghemite on the pH of an Aqueous Solution
- 1 September 1993
- journal article
- research article
- Published by Oxford University Press (OUP) in Bulletin of the Chemical Society of Japan
- Vol. 66 (9) , 2751-2753
- https://doi.org/10.1246/bcsj.66.2751
Abstract
We examined the dependence on the pH value of the heat of immersion of maghemite in an aqueous system, and confirmed the peculiar finding that the pH value at the minimum heat occurs not at PZC, but at a higher pH. The reason for this is the existence of two types of surface hydroxyl groups (basic and acidic) which comprise all of the surface hydroxyl groups on maghemite. Moreover, the heat required for the adsorption of a proton on the surface hydroxyl group is higher than that for its desorption.Keywords
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