Sorption of U(VI) on dolomite in a dilute carbonate solution: behavior investigation and mechanism probe
Author:
Yin Xiaoyu1, Wu Peng1, Zhao Yufan1, Shi Shilong1, Liu Jun2, Li Feize1, Liao Jiali1, Liu Ning1, Yang Yuanyou1, Lan Tu1ORCID
Affiliation:
1. Key Laboratory of Radiation Physics and Technology of the Ministry of Education , Institute of Nuclear Science and Technology, Sichuan University , Chengdu 610064 , P.R. China 2. College of Nuclear Technology and Automation Engineering , Chengdu University of Technology , Chengdu 610059 , P.R. China
Abstract
Abstract
The U(VI) sorption behavior on dolomite was systematically investigated in a dilute carbonate solution using batch technique. The distribution coefficients (K
d) increased with the increasing time and temperature, but decreased with the increase of initial U(VI) concentration and ionic strength. As the initial pH increased from 2.0 to 10.5, the K
d values first increased and then decreased, mainly due to the transition from electrostatic attraction to repulsion caused by the changes in U(VI) species. The sorption process was well-described by pseudo-second-order kinetic and Freundlich isotherm models, and was spontaneous, endothermic, heterogeneous, and pH-dependent. In the presence of HA/FA, at low pH, more HAs/FAs were adsorbed on dolomite surface, providing more sorption sites for the positively charged U(VI) species, and promoting the U(VI) sorption. At high pH, more HAs/FAs were dispersed in solution, encapsulating the negatively charged U(VI) species in aggregates, and inhibiting the U(VI) sorption. The promoting and inhibiting effects of HA on the sorption process are obviously stronger than FA. XPS spectra indicated that the surface ‒OH and CO3
2− on the hydroxylated dolomite and the –OH groups in HA/FA may be involved in U(VI) sorption. The results reported here provide valuable references for further understanding U(VI) migration in geological media.
Funder
National Natural Science Foundation of China Natural Science Foundation of Sichuan Province
Publisher
Walter de Gruyter GmbH
Subject
Physical and Theoretical Chemistry
Reference47 articles.
1. Miller, J. M., Wong, P. C. F. 19 – Canada: experience of radioactive waste (RAW) management and contaminated site cleanup. In Radioactive Waste Management and Contaminated Site Clean-Up; Lee, W. E., Ojovan, M. I., Jantzen, C. M., Eds.; Woodhead Publishing: Oxford, 2013; pp. 612–635. 2. Zhao, X. G., Wang, J., Qin, X. H., Cai, M., Su, R., He, J. G., Zong, Z. H., Ma, L. K., Ji, R. L., Zhang, M., Zhang, S., Yun, L., Chen, Q. C., Niu, L. L., An, Q. M. In-situ stress measurements and regional stress field assessment in the Xinjiang candidate area for China’s HLW disposal. Eng. Geol. 2015, 197, 42; https://doi.org/10.1016/j.enggeo.2015.08.015. 3. Gao, H., Rao, Z., Li, G., Liu, X., Liu, P., Li, H., Liu, S., Gong, Z., Guo, C., Ni, F. Evaluation of the suitability of clay rock sites for geological disposal of high-level radioactive waste in the Tamusu area, Inner Mongolia, China. J. Radioanal. Nucl. Chem. 2023, 332, 47; https://doi.org/10.1007/s10967-022-08654-x. 4. Deniau, I., Derenne, S., Beaucaire, C., Pitsch, H., Largeau, C. Occurrence and nature of thermolabile compounds in the Boom clay kerogen (Oligocene, underground Mol Laboratory, Belgium). Org. Geochem. 2004, 35, 91; https://doi.org/10.1016/j.orggeochem.2003.10.010. 5. Bardelli, F., Mondelli, C., Didier, M., Vitillo, J. G., Cavicchia, D. R., Robinet, J.-C., Leone, L., Charlet, L. Hydrogen uptake and diffusion in Callovo-Oxfordian clay rock for nuclear waste disposal technology. Appl. Geochem. 2014, 49, 168; https://doi.org/10.1016/j.apgeochem.2014.06.019.
|
|