Sorption of Se species on mineral surfaces, part I: Batch sorption and multi-site modelling

Development and application of an advection-dispersion model for data analysis of electromigration experiments with intact rock cores

“…It seems, therefore, that both iodide and selenite are effectively non-sorbing in the rock core investigated in this work. For iodide, this is expected (André et al, 2009;Ohlsson and Neretnieks, 1997), while for selenite the results from batch experiments with crushed rocks suggested that it is a weakly sorbing species, with 𝐾 d values on the order of 2.95×10 -4 m 3 /kg for Forsmark and Laxemar granites (Crawford, 2010) and 2.0×10 -3 m 3 /kg for Grimsel granodiorite (Li et al, 2018). We found, however, that the assumption of selenite as a sorbing species always made the curvature of the simulated breakthrough curves to deviate clearly from that obtained in the experiments, especially at the moments around the breakthrough time, when the advection-dispersion model or the reactive transport model was used.…”

“…To determine accurately the diffusion and sorption properties of radionuclides, extensive studies have been performed by block scale diffusion experiments (García-Gutiérrez et al, 2006;Ikonen et al, 2016), through-diffusion experiments (Nilsson et al, 2010;Tachi et al, 2015) and batch sorption experiments (Li et al, 2018;Soderlund et al, 2016aSoderlund et al, , 2016b. Among these experimental methods, batch sorption experiments (Crawford, 2010) can only be used to evaluate the sorption properties of radionuclides on crushed rocks.…”

Sorption of selenium species onto phlogopite and calcite surfaces: DFT studies

“…The estimated surface site density values were used in our PHREEQC modelling based on titration, sorption edge and sorption isotherm experimental results of Se(IV) sorption on phlogopite (Li et al, 2018;Li et al, 2019). A multi-site surface complexation model was successfully developed by treating the (001) and ( 110) surfaces as weak sorption sites in combination with strong sorption sites with a low site density (0.00068 sites/nm 2 ).…”

“…Figure 9. Experimental data of Se(IV) sorption on biotite in Grimsel groundwater simulant as a function of Se concentration from 10 -10 M to 10 -3 M and the continuous line is the simulated data with surface complexation model (Li et al, 2018).…”

“…However, there is still little information about the sorption sites of these two minerals nor the mechanisms of selenium sorption when interpreting the experimental sorption results. The sorption of selenium species on biotite or calcite was normally ascribed to a surface complexation mechanism involving two types of surface hydroxyl groups, the strong sorption sites ( S S OH) and weak sorption sites ( S W OH) (Ervanne et al, 2016;Li et al, 2018;Missana et al, 2009a). Moreover, it is crucial to explore the sorption mechanism of selenium species onto these two minerals on Journal Pre-proof J o u r n a l P r e -p r o o f the molecular scale by molecular modelling methods, for example, based on Density Function Theory (DFT).…”