Kinetic studies of the quartz/sand, Eu3+ and humic acid ternary system

The interactions of Eu3+ ions, humic acid and quartz in ternary system experiments have been studied. The variations in the amount of humic acid and Eu3+ with time have been determined as a function of humic acid concentration. The desorption of both humic acid and europium have also been measured. A simple mathematical model has been developed that is able to predict the behaviour of both metal ion and humic acid. There is multi-component behaviour in the experiments, and the modelling suggests that for the sorption step at least, heterogeneity of the surface binding sites dominates. However, there is hysteresis in the desoprtion behaviour of the humic, which could be due to chemical and/or size fractionation on the quartz surface.