Sorption of americium / europium onto magnetite under saline conditions: Batch experiments, surface complexation modelling and X-ray absorption spectroscopy study vol 561, pg 708, 2020)

Retention of europium by magnetite of >99.5% was found above pH 6.4 for all ionic strengths for europium concentration of 6 × 10m. No ionic strength effect was observed in this pH range. At 1.2 × 10m europium concentration, 95 ± 4% sorption was found above pH 7.5 for I = 1 m and above pH 8.0 for I = 3.5 m and 6.67 m. A small ionic strength effect was observed in this case. X-ray absorption spectroscopy (XAS) results are consistent with the batch sorption experiment outcomes, showing an insignificant effect of ionic strength on the pH dependent sorption. Results from potentiometric titrations of the solid phase, batch sorption experiments and spectroscopy were interpreted consistently with a charge distribution multi-site (CD-MUSIC) triple layer surface complexation model assuming surface coordination of the metal ion via a tridentate binding mode.