A novel assembly method was used to prepare the sulfhydryl functionalized magnetic SBA-15 (SH-M-SBA-15). The physicochemical properties of SH-M-SBA-15 were characterized by TEM, XRD, EDS, FT-IR, BET, and VSM. Batch adsorption experiments were conducted to investigate the influence of initial uranium concentration, dosage of adsorbent, pH values, contact time, and temperature on the adsorption efficiency and behaviors. The adsorption types were analyzed from the aspects of kinetic, isotherms, and thermodynamic. The results show that the specific surface area of SH-M-SBA-15 is 316.67 m/g, which is smaller than that of SBA-15 (692.18 m/g). However, compared with SBA-15, SH-M-SBA-15 has more surface sulfhydryl functional groups. The addition of this group can improve the adsorption of uranyl ions by SH-M-SBA-15. The optimal adsorption conditions were adsorption dosage 40 mg/L, pH 6, temperature 35 °C, contact time 180 min, and initial uranium concentration 35 mg/L. Under this condition, the maximum adsorption amount of uranyl ion by SH-M-SBA-15 can reach 804.79 mg/g, which is much higher than the highest adsorption capacity of uranyl ion by SBA-15 (146.23 mg/g). The adsorption process was better depicted by the Langmuir isotherm model. The process was consistent with the quasi-second-order model. ΔG was negative and ΔH was positive, indicating spontaneous and endothermic adsorption.
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http://dx.doi.org/10.1007/s11356-019-06329-x | DOI Listing |
J Am Chem Soc
January 2025
Key Laboratory of Polyoxometalate and Reticular Material Chemistry of the Ministry of Education, Faculty of Chemistry, Northeast Normal University, Changchun 130024, P. R. China.
Uranium (U), a high-performing, low-emission energy source, is driving sustainable economic growth. Herein, we synthesized two crystalline phases (HPOC-α and β) by an unreported amidoxime organic cage used for uranium capture. The revealed crystal structures and uranium adsorption test showed that accessible functional groups were essential to uranyl ions sorption.
View Article and Find Full Text PDFSmall
December 2024
Key Laboratory of Photonic and Electronic Bandgap Materials Ministry of Education, School of Physics and Electronic Engineering, Harbin Normal University, Harbin, 150025, China.
Extracting uranium from seawater is crucial for tapping oceanic resources vital to future energy supply. This study synthesized a novel nitrogen vacancy carbon nitride (NCN) grafted polyethyleneimine (PEI) composite material (NCNP). Experiments and molecular dynamics simulations reveal that NCNP effectively hinders the diffusion of uranyl ions (UO ) to the NCN surface, thereby inhibiting electron transfer reactions.
View Article and Find Full Text PDFInorg Chem
December 2024
State Key Laboratory for Mineral Deposits Research, School of Earth Sciences and Engineering, Nanjing University, Nanjing, Jiangsu 210023, China.
In this study, we employed classical molecular dynamics (CMD) and first-principles molecular dynamics (FPMD) simulations to investigate the speciation of uranyl in carbonate-rich hydrothermal solutions. The association constants (log) of uranyl carbonate complexes were derived from the potential of mean forces (PMFs) obtained from CMD simulations, and the acid constants (ps) of uranyl aqua ions were calculated using the FPMD-based vertical energy gap method. The results showed that uranyl ions could form stable mono- and bi-carbonate complexes at elevated temperatures and that uranyl aqua ions strongly hydrolyzed in neutral solutions at temperatures exceeding 473 K.
View Article and Find Full Text PDFInorg Chem
December 2024
Texas Tech University, Department of Chemistry and Biochemistry, Lubbock, Texas, United States, 79401.
Uranium is most stable when it is exposed to oxygen or water in its +6 oxidation state as the uranyl (UO) ion. This ion is subsequently particularly stable and very resistant to functionalization due to the inverse trans effect. Uranyl oxo ligands are typically not considered good hydrogen bond acceptors due to their weak Lewis basicity; however, the ligands bound in the equatorial plane greatly affect the strength of the oxo ligands' hydrogen bonding.
View Article and Find Full Text PDFInorg Chem
December 2024
Department of Chemistry, University of Kansas, 1567 Irving Hill Road, Lawrence, Kansas 66045, United States.
Interconversion of the oxidation states of uranium enables separations and reactivity schemes involving this element and contributes to technologies for recycling of spent nuclear fuels. The redox behaviors of uranium species impact these processes, but use of electrochemical methods to drive reactions of molecular uranium complexes and to obtain molecular insights into the outcomes of electrode-driven reactions has received far less attention than it deserves. Here, we show that electro-reduction of the uranyl ion (UO) can be used to promote stepwise functionalization of the typically unreactive oxo groups with exogenous triphenylborane (BPh) serving as a moderate electrophile, avoiding the conventional requirement for a chemical reductant.
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