Iron oxide photodissolution

Except for phthalic acid, all other carboxylic acids studied induce considerable increases in the light compared to the dark values (the relatively high rate of iron oxide dissolution induced by oxalic acid has been extensively studied (5,8). Phthalic acid actually appears to stabilize the iron oxide against photodissolution despite the solution phase complex exhibiting some photoactivity. 

Litter, M.I. Baumgartner, E.C. Urmtia, G.A. Blesa, M.A. (1991) Photodissolution of iron oxides. 3. Interplay of photochemical and thermal processes in maghemite/carboxylic acid systems. Environ. Sci. Technol. 25 1907-1913... 

Linak WP, Miller CA (2000) Comparison of particle size distributions and elemental partitioning from the combustion of pulverized coal and residual fuel oil. J Air Waste Manage Assoc 50 1532-1544 Litter Ml, Villegas M, Blesa MA (1994) Photodissolution of iron-oxides in malonic-acid. Can J Chem 72 2037-2043... 

At low pH, where resorption reactions are minimal, the photodissolution process may be represented as a two-step process involving adsorption of ligand L to metal oxide surface sites followed by detachment of reduced metal ions that is, for an iron oxyhydroxide ... 

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