Speciation of Eu(Ⅲ) on γ-Al_2O_3:A Fluorescence Spectroscopy Study

The speciation of Eu(Ⅲ) on γ-Al_2O_3 is investigated by fluorescence spectroscopy study in the presence of alumina, humic acid and humic acid-alumina. The experiments are performed at 0.1 mol/kg NaClO_4, pH=5.3±0.1 and under N_2 atmosphere. The results show that sorption of Eu(Ⅲ) at HA coated alumina surface is strongly influenced by humic acid and the species of Eu(Ⅲ) is dominated by both alumina particles and humic acid sorbed onto the mineral surface in the presence of humic acid-alumina. The study of effect of humic acid on the sorption and species of Eu(Ⅲ) onto mineral surface is important to understand fully the behavior of Eu(Ⅲ), or its analogue trivalent lanthanides and actinides in environment.