## 3 Results
### Modeling Adsorption from Uranium in Solution
#### 3.2.3 Transport Modeling in URP Columns
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & & \multicolumn{4}{c}{URP6} \\ \hline
**Sample Type** & **ID Sample** & \({}^{234}\)**U Bq kg\({}^{-1}\)** & \({}^{238}\)**U Bq kg\({}^{-1}\)** & **RQ (\%)** & \({}^{238}\)**U mg kg\({}^{-1}\)** \\ \hline \multirow{6}{*}{Solid} & URP6 CSC & \(1058\pm 21\) & \(1124\pm 22\) & 78 & 91 \\  & URP6 FSC & \(918\pm 9\) & \(865\pm 9\) & X & 70 \\  & URP6 CS & \(782\pm 17\) & \(772\pm 17\) & 78 & 63 \\  & URP6 FS & \(620\pm 14\) & \(628\pm 14\) & 81 & 51 \\  & URP6C\({}_{1}\) & \(1324\pm 24\) & \(1362\pm 25\) & 100 & 110 \\  & URP6C\({}_{2}\) & \(1304\pm 23\) & \(1272\pm 23\) & 79 & 103 \\ \hline \multirow{2}{*}{Supernatant solution} & \multicolumn{4}{c}{\({}^{234}\)U Bq L\({}^{-1}\)} & \({}^{238}\)U Bq L\({}^{-1}\) & RQ (\%) & \({}^{238}\)U mg L\({}^{-1}\) \\ \cline{2-6}  & WURP6 CSC & \(1.19\pm 0.01\) & \(1.29\pm 0.01\) & X & 0.10 \\ \cline{1-1} \cline{2-6}  & WURP6 FSC & \(1.30\pm 0.01\) & \(1.41\pm 0.02\) & X & 0.11 \\ \hline \hline \end{tabular}  
* The uncertainty of the supernatant solution experiments is approximately 15%, see Appendix A.1.  
\end{table} 
Table 7: U activity concentration in solids samples and the supernatant solutions * of the URP6 column. \begin{table}
\begin{tabular}{c c c c c c} \hline \hline  & & \multicolumn{4}{c}{URP12} \\ \hline
**Sample Type** & **ID Sample** & \({}^{234}\)**U Bq kg\({}^{-1}\)** & \({}^{238}\)**U Bq kg\({}^{-1}\)** & **RQ (\%)** & \({}^{238}\)**U mg kg\({}^{-1}\)** \\ \hline \multirow{6}{*}{Solid} & URP12 CSC & \(234\pm 3\) & \(244\pm 3\) & X & 20 \\  & URP12 FSC & \(79\pm 1\) & \(82\pm 1\) & X & 7 \\ \cline{1-1}  & URP12 CS & \(253\pm 4\) & \(305\pm 5\) & 78 & 25 \\ \cline{1-1}  & URP12 FS & \(95\pm 2\) & \(99\pm 2\) & 81 & 8 \\ \cline{1-1}  & URP12C\({}_{1}\) & \(464\pm 7\) & \(451\pm 7\) & 98 & 37 \\ \cline{1-1} \cline{2-6}  & URP12C\({}_{2}\) & \(169\pm 3\) & \(172\pm 3\) & 94 & 14 \\ \hline \multirow{2}{*}{Supernatant solution} & \multicolumn{4}{c}{\({}^{234}\)U Bq L\({}^{-1}\)} & \({}^{238}\)U Bq L\({}^{-1}\) & & \({}^{238}\)U mg L\({}^{-1}\) \\ \cline{1-1} \cline{2-6}  & WURP12 CSC & \(0.46\pm 0.01\) & \(0.58\pm 0.01\) & 80 & 0.05 \\ \cline{1-1}  & WURP12 PSC & \(0.33\pm 0.005\) & \(0.43\pm 0.01\) & \(\chi\) & 0.03 \\ \hline \hline \end{tabular}  
* The uncertainty of the supernatant solution experiments is approximately 15%, see Appendix A.1.  
\end{table} 
Table 8: U activity concentration in solids samples and the supernatant solutions * of URP12 column. Tomography of URP6 and URP12 Column Profiles  
The spatial distribution of uranophane concerning the solution flow in the column was observed in the images of the sediments extracted by the URP6 and URP12 cores. Typical silt and clay compaction was observed by separating each column's FSD, CSC, and FSC segments. For this reason, computer tomography scans of the spaces in the two lower segments were not obtained. Figure 7A,B show the tomographic images of the URP6 FSD and URP12 FSD segments. The tomography presents the quantitative results by density difference. The FSD tomography of URP6 shows a high density of uranophane horizon particles at the top and the beginning of particle movement, presumably dragged by the solution flow. The FSD tomography of URP12 shows the rearrangement of the grains to the lower part of the segment towards the contact with CSC. The tomography probability graph suggests the drag of the finest uranophane particles transported toward the CSC. This result explains the higher U concentration values of CSC compared to FSC