Retardation of hexavalent uranium in muscovite environment: a batch study

Abstract

The sorption of hexavalent uranium on muscovite as a function of pH, background electrolyte, temperature and humic acid (HA) was investigated in detail using batch experiments. The results showed that the uranium sorpiton on muscovite was kinetic fast, the kinetic process was fitted well by pseudo-second-order kinetic model. The sorption of uranium depended strongly on pH while weakly on background electrolyte concentration, indicating that surface complexation dominated the sorption process. The escalation of temperature and humic acid concentration were favorable to uranium sorption on muscovite. The sorption isotherms at pH 6.0 could be described better by Langmuir model than Freundlich or Dubinin-Radushkevich (D-R) model, thermodynamic data indicated that the uranium sorption process on muscovite was spontaneous and endothermic process. The findings in present work can provide important experimental reference for understanding the environmental behavior of uranium in mica-rich terrains.

Adsorption of uranium (VI) from aqueous solutions using boron nitride/polyindole composite adsorbent

“…The increase in pH from 5.0 to 5.5 resulted in the formation of negatively charged U (VI) species, which enhanced the electrostatic attraction, thus increasing the adsorption 9,48,55,56 . Above pH 5.5, anionic species of U (VI) complexes such as (UO 2 ) 3 (OH) 7− , UO 2 (OH) 3− , and UO 2 (OH) 4 2− were formed and this leads to a significant decrease in adsorption 53,57 …”

“…9,48,55,56 Above pH 5.5, anionic species of U (VI) complexes such as (UO 2 ) 3 (OH) 7À , UO 2 (OH) 3À , and UO 2 (OH) 4 2À were formed and this leads to a significant decrease in adsorption. 53,57 As seen in the pH PZC graph (Figure S9), at low pH values, adsorbent surface was positively charged, while it was negatively charged as pH values increased. The protons and cations in the solution are more adsorbed on surface at low pH, while as the pH rises, deprotonation on the adsorbent surface begins and the retention of hydroxyl ions on the surface increases.…”

Relativistic DFT Probe for Reaction Energies and Electronic/Bonding Properties of Polypyrrolic Hetero-Bimetallic Actinide Complexes: Effects of Uranylendo-Oxo Functionalization

“…The reported results are crucial in quality control and monitoring programs for the assessment of radionuclide migration. The impact of the study significantly evaluated the risks associated with radioactive contamination. , The environmental modeling of uranium interstitial compositions of nonstoichiometric oxides is maximal representative of real environmental biogeochemical reactions of uranium sorption onto sediments. , …”

“…The impact of the study significantly evaluated the risks associated with radioactive contamination. 8,9 The environmental modeling of uranium interstitial compositions of nonstoichiometric oxides is maximal representative of real environmental biogeochemical reactions of uranium sorption onto sediments. 10,11 In solution and the solid state, the hexavalent uranyl is able to interact with actinyl or actinide to form cation−cationinteraction (CCI) complexes.…”