Competitive adsorption of boric acid and chromate onto alumina in aqueous solutions.
The competitive adsorption of boric acid and chromate from aqueous solutions by alumina has been investigated by spectrophotometry at pH 8, ionic strength = 0.0, 0.1 and 1.0 M NaClO4, T = 22 ± 3 °C and under normal atmospheric conditions. The experimental data show that addition of excess boric acid in the system leads to the increase of Cr(VI) concentration in solution, indicating the replacement of adsorbed chromate by boron on the alumina surface. Data evaluation results in the determination of the competition reaction constant and the formation constant of the Cr(VI) surface complexes, which are logKCr(VI)-B(III) = -3.5 ± 0.2 and logβ*Cr = 7.6 ± 0.3, respectively.
Department of Chemistry, University of Cyprus, P.O. Box 20537, Cy-1678 Nicosia, Cyprus E-mail: pspasch@ucy.ac.cy.
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Demetriou
Department of Chemistry, University of Cyprus, P.O. Box 20537, Cy-1678 Nicosia, Cyprus E-mail: pspasch@ucy.ac.cy.
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Pashalidis
D000327:Adsorption; D000537:Aluminum Oxide / Q000737:chemistry*; D001888:Boric Acids / Q000737:chemistry*; D002840:Chromates / Q000737:chemistry*; D002857:Chromium / Q000737:chemistry
D001888:Boric Acids; D002840:Chromates; D002857:Chromium; D000537:Aluminum Oxide; C032688:boric acid