Date of Award
Master of Science in Oceanography
The ultraviolet absorbance data from experiments conducted at constant pH, T(Fe), and variable [B(OH)3] were used to determine Fe*BB1 and Fe*BB2, the stability constants of FeB(OH)42+ and Fe(B(OH4)2+, respectively, in a 0.7 NaClO4 solution at 25*C. The data were analyzed taking into account the absorbances due to Fe3+ and FeOH2+. In addition, one or more ferric borate species were assumed to be present and the appropriate model was fitted to the data. The one species model (FeB(OH)42+) and the two species model (FeB(OH)42+ and Fe(b(OH4)2+) gave the best fits. However, the two species model was found to describe the ferric borate equilibrium better over a wider range of pH. The estimates obtained for the two ferric borate species model were FeB*B1 = 1.0 ± 0.2 x 10-2 and FeB*B2 = 2 ± 1 x 10-5. The model which included only FeB(OH)42+ estimated FeB*B1 = 5.7 ± 0.6 x 10-3. The contribution of FeB(OH)42+ and Fe(B(OH)4)2+ to iron speciation in seawater at pH 8.2 is not significant, based on the stability constants determined by the two species model.
Elrod, Jane A., "Determination of the Stability Constants of Ferric Borate at the Ionic Strength of Seawater" (1979). Open Access Master's Theses. Paper 2077.