Alkaline leaching characteristics of uranium from Lincang coal: Correlation with the dissolution of coal humic substances

Ning, Y.N.; Luo, Zhiqiang; Li, Yilian; Yang, Zhe; Liu, Danqing; Zhang, Yangyang

doi:10.1016/j.fuel.2021.121507

Cited by 8 publications

(4 citation statements)

References 70 publications

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“…As shown in Figure 7, EEM was used to characterize HSs before and after adsorption. As previously reported [56], the fluorescence of HSs included five regions. Among them, FA-like components at Ex/Em = 200-250/380-550 nm and HA-like substances at Ex/Em = 250-400/380-550 nm.…”

Section: Adsorption Mechanismsmentioning

confidence: 63%

The Adsorption Behaviors and Mechanisms of Humic Substances by Thermally Oxidized Graphitic Carbon Nitride

Wang

Yue

et al. 2023

Toxics

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Thermal oxidation is efficient for enhancing the photocatalysis performance of graphitic carbon nitride (g-C3N4), while its effect on adsorption performance has not been fully studied, which is crucial to the application of g-C3N4 as adsorbents and photocatalysts. In this study, thermal oxidation was used to prepare sheet-like g-C3N4 (TCN), and its application for adsorption of humic acids (HA) and fulvic acids (FA) was evaluated. The results showed that thermal oxidation clearly affected the properties of TCN. After thermal oxidation, the adsorption performance of TCN was enhanced significantly, and the adsorption amount of HA increased from 63.23 (the bulk g-C3N4) to 145.35 mg/g [TCN prepared at 600 °C (TCN-600)]. Based on fitting results using the Sips model, the maximum adsorption amounts of TCN-600 for HA and FA were 327.88 and 213.58 mg/g, respectively. The adsorption for HA and FA was markedly affected by pH, alkaline, and alkaline earth metals due to electrostatic interactions. The major adsorption mechanisms included electrostatic interactions, π-π interactions, hydrogen bonding, along with a special pH-dependent conformation (for HA). These findings implied that TCN prepared from environmental-friendly thermal oxidation showed promising prospects for humic substances (HSs) adsorption in natural water and wastewater.

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Section: Adsorption Mechanismsmentioning

confidence: 63%

The Adsorption Behaviors and Mechanisms of Humic Substances by Thermally Oxidized Graphitic Carbon Nitride

Wang

Yue

et al. 2023

Toxics

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“…As for U, the concentrations were less than 10 mg/L in an alkaline solution containing 17 to 72 g/L of free NaOH (pH ≥ 13.63) (Figure 2E). In the leaching process, U in the IREEs-LLR first dissolved in the form of soluble uranyl hydroxide complexes at a pH below 9 at 368 K, but then, with the increase of pH, the soluble U(VI) species, as shown in (Figure 2F), gradually formed Na 2 U 2 O 7 precipitates, 28 resulting in the presence of trace soluble U(VI).…”

Section: Leaching Al In Alkaline Solutionsmentioning

confidence: 99%

“…25,26 As to U, U also could be dissociated via the highly soluble uranyl complexes. For instance, U could be dissolved into NaOH-Na 2 CO 3 and Na 2 CO 3 -NaHCO 3 media with the leaching yield above 90 wt % in the tailings (0.08 wt % U), 27 coal(11.3 wt % U), 28 and M(OH)x•nH 2 produced by mineral (0.67 wt % U), 29 respectively.…”

Section: Introductionmentioning

confidence: 99%

“…It could be anticipated that the dissociation of Al in IREEs-LRR could be achieved by leveraging the difference in solubility between REEs, U(Th) and Al in alkaline solutions, because the Al(OH) 3 could react with concentrated NaOH to form soluble NaAl(OH) 4 . , As to U, U also could be dissociated via the highly soluble uranyl complexes. For instance, U could be dissolved into NaOH-Na 2 CO 3 and Na 2 CO 3 -NaHCO 3 media with the leaching yield above 90 wt % in the tailings (0.08 wt % U), coal(11.3 wt % U), and M(OH)x·nH 2 produced by mineral (0.67 wt % U), respectively.…”

Section: Introductionmentioning

confidence: 99%

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Disposal Strategy of Ion-Adsorption Rare Earth Elements Low-Level Radioactive Residues: Reduction Emission and Recovery for Aluminum and Uranium by Alkaline and Alkalescent Media

Chang,

Li,

Han

et al. 2024

ACS Sustainable Resour. Manage.

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Hindered by the separation among radioactive elements, aluminum (Al), and rare earth elements (REEs), acid methods encounter persistent obstacles in reduction emission of ion-adsorption rare earth elements low-level radioactive residues (IREEs-LRR). This work reported a stepwise strategy for the reduction of emission and recovery of Al and uranium (U) from IREEs-LRR by alkaline and alkalescent media. As one of the main phases, Al(III)-containing compounds of IREEs-LRR were first converted into soluble NaAl(OH) 4 with NaOH solution at ordinary pressure. Na 2 U 2 O 7 and the adsorbed state U(VI), as detected by speciation, were then transformed into soluble uranyl carbonate in a Na 2 CO 3 -NaCit solution. The total removal yields of Al and U approached 97 and 94 wt %, respectively, engendering an 84 wt % loss weight of IREEs-LRR. Additionally, the REEs content in the residues increased from 0.88 to 3.6 wt %, while the specific activity of U decreased from 5.6 to 1.9 Bq/g. The mechanism was related to the NaOH-mediated dissociation of Al(III) polymeric complexes coupled with the enhanced dissolving capacity of uranium (U(VI)) complexes in alkalescent medium. This paper provides a novel strategy for reducing residual radioactivity, enriching REEs, and recovering valuable Al and U from IREEs-LRR.

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Quantitative characterization of seepage behavior in rough fracture considering hydromechanical coupling effect: an experimental study

Zhang

Yang

et al. 2022

Acta Geophys.

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Alkaline leaching characteristics of uranium from Lincang coal: Correlation with the dissolution of coal humic substances

Cited by 8 publications

References 70 publications

The Adsorption Behaviors and Mechanisms of Humic Substances by Thermally Oxidized Graphitic Carbon Nitride

The Adsorption Behaviors and Mechanisms of Humic Substances by Thermally Oxidized Graphitic Carbon Nitride

Disposal Strategy of Ion-Adsorption Rare Earth Elements Low-Level Radioactive Residues: Reduction Emission and Recovery for Aluminum and Uranium by Alkaline and Alkalescent Media

Quantitative characterization of seepage behavior in rough fracture considering hydromechanical coupling effect: an experimental study

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