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Complexation reactions of phthalic acid and aluminium(III) with the surface of goethite

Journal Article · · Geochimica et Cosmochimica Acta; (United States)
Complexation reactions of phthalic acid at the goethite-solution interface have been investigated in the absence and the presence of Al(III) in order to evaluate an equilibrium model applicable in chemical modeling. Phthalic acid was chosen as a model compound for natural organic substances. The study was performed as potentiometric titrations in 0.100 M NaNO{sub 3} at 298.2 K using a glass electrode. Evaluation of experimental data was based on the constant-capacitance model (K = 1.28 F m{sup {minus}2}). Evaluation of experimental data was based on the constant-capacitance model (K = 1.28 F m{sup {minus}2}). Complexation of phthalic acid (H{sub 2}L) at the surface of goethite is rather weak and results in the formation of mononuclear species. In the presence of Al(III), the adsorption behavior of phthalic acid indicated formation of ternary surface complexes in the region 4 {le} {minus}log (H{sup +}) {le} 7. Additional complexes occurring in the four-component system are described by the equilibria and intrinsic equilibrium constants listed in the paper.
OSTI ID:
7049622
Journal Information:
Geochimica et Cosmochimica Acta; (United States), Journal Name: Geochimica et Cosmochimica Acta; (United States) Vol. 55:12; ISSN GCACA; ISSN 0016-7037
Country of Publication:
United States
Language:
English