Dissociation pathways and species distribution of aluminum bound to an aquatic fulvic acid

A ligand-exchange reaction between Al-fulvic acid (FA) complexes and lumogallion (Lum), Al-FA+Lum→Al-Lum+FA, was investigated by following the appearance of the fluorescent complex AlLum. Rate data fit a model of simultaneous first-order reactions and indicated that the concentration of the slowest reacting component increased with increasing fulvic acid concentration. Small changes in pH (5.0-5.5) and in ionic strength (I=0.02-0.11)had no effect on the observed rates