Kinetics of aluminium fluoride complexation in single- and mixed-ligand systems.
The complexation reaction between Al(3+) and fluoride was studied over concentration ranges 2-50muM fluoride, 0.5-500muM aluminium, pH 2.5-5.0 at ionic strength 0.1 and temperatures of 298 and 283 K. The initial rate of formation of AlF(2+) was strongly dependent on pH, reaching a minimum at pH 3, and was considerably slower at the lower temperature. Addition of salicylate increased the reaction rate, probably because of the corresponding increase in the initial concentration of AlOH(2+). These effects of pH, temperature and competing ligands will therefore be critical in determining the composition of acid natural water systems and in particular the speciation of soluble aluminium.
Townsend
G S
GS
Department of Geography, The University, Cambridge, CB2 3EN, U.K.
Bache
B W
BW