Abstract
Effect of pH and ionic strength on the ligand exchange reaction between ferric fulvic acid and siderophore (desferrioxamine B) was examined in the range from pH 6.0 to 9.0 and ionic strength from 0.01 to 0.7 M. The results showed that higher pH rendered higher ligand exchange reaction rate in the pH greater than 8.0. On the other hand, in the pH below 8.0, the ligand exchange rate constants was found to vary less than an order of magnitude. Ionic strength resulted in insignificant changes of the ligand exchange rate constants. These results suggest that pH plays important role in the ligand exchange reaction in coastal and seawaters and the lakes under algal bloom where pH typically exceeds 8.0.
