In this study, a novel sponge phosphoric acid functionalized porous composite adsorbent (named SPCCHC) was prepared from chitosan and chlorella hydrothermal charcoal. Kinetics and thermodynamics experiments showed that the theoretical maximum adsorption capacity of SPCCHC to U(VI) is 579.27 mg/g (288 K, pH = 6.5), indicating a spontaneous exothermic reaction. SPCCHC showed good adsorption selectivity for uranium in the adsorption studies of simulated seawater and a mixed solution of uranium-vanadium. The characterization of SPCCHC before and after U(VI) adsorption proves that the introduction of the phosphate group can greatly improve the adsorption effect of the adsorbent on uranium, particularly the distribution coefficients of uranium and vanadium differ by up to 89.5 times. At the same time, SPCCHC has good recycling performance, which is expected to be used in natural seawater uranium extraction.
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http://dx.doi.org/10.1016/j.carbpol.2022.120270 | DOI Listing |
Chemistry
March 2025
North China Electric Power University, Beinong Road No.2, CHINA.
Photocatalytic technology has attracted considerable attention in recent years due to its significant potential in environmental protection and energy conversion. Covalent organic frameworks (COFs), a novel class of porous materials, demonstrate remarkable photocatalytic performance owing to their high surface areas, tunable pore sizes, permanent porosities, and customizable functionalities. This review provides a comprehensive overview of the application of COFs in photocatalysis.
View Article and Find Full Text PDFSci Rep
March 2025
Materials Science and Technology Division, Los Alamos National Laboratory, Los Alamos, NM, 87545, USA.
Performing reliable Rietveld analysis on tens or hundreds of powder diffraction datasets from parametric or time-resolved experiments often poses a bottleneck in extracting meaningful results from the data. While automated analysis of data has recently been demonstrated, high temperature annealing studies, during which phase transformations occur and lattice parameters may change due to repartitioning of elements, are prime examples where automation by a simple phase identification from a database of room temperature structures or automation by sequential refinements is likely to fail. To enable reliable, efficient, automated Rietveld analysis, we present a Python package named Spotlight, building on established Rietveld packages such as MAUD, GSAS, or GSAS-II, which extends the refinement of best fit parameters to a global optimization using an ensemble of optimizers leveraging hierarchical parallel execution on high-performance computing clusters.
View Article and Find Full Text PDFNat Commun
March 2025
Frontiers Science Center for Rare Isotopes, School of Nuclear Science and Technology, Lanzhou University, Lanzhou, China.
Selective extracting uranium from seawater is quite challenging, particularly the presence of vanadium, which poses a significant obstacle for most amidoxime absorbents. Adsorbents with size-matched pores and coordination environment can improve the uranium selectivity but usually deteriorate the adsorption capacity. Herein, a dynamically matched spatial coordination strategy is proposed to improve the performance of uranium extraction.
View Article and Find Full Text PDFACS Omega
March 2025
Center for Radiation Chemistry Research, Idaho National Laboratory, 1955 N. Fremont Avenue, Idaho Falls, Idaho 83415, United States.
The direct dissolution of voloxidized used nuclear fuel (UNF) into an organic solution-comprised of diluent and specialized extractants-poses a promising alternative to the traditional liquid-liquid solvent extraction approach to reprocessing UNF. However, moving to direct dissolution removes the presence of a concentrated nitric acid aqueous phase, which has been shown to significantly influence the radiolytic longevity of extractants in conventional extraction flowsheets. Given the limited knowledge of radiation effects under direct dissolution conditions, here we present a time-resolved and dose-accumulation study on the impact of direct dissolution conditions on the radiolytic longevity of two candidate butyramide extractants, -di(2-ethylhexyl) butyramide (DEHBA) and -di(2-ethylhexyl)isobutyramide (DEHBA), in pre-equilibrated -dodecane solvent in the presence and absence of process-relevant metal ions, specifically, uranium and rhenium.
View Article and Find Full Text PDFJ Contam Hydrol
February 2025
Division of Geosciences and Environmental Engineering, Luleå University of Technology, S-97 187 Luleå, Sweden.
Uranium (U) release from mining has been typically associated with former U mine sites, but trace U levels in iron or base metal ores can also lead to U mobilization into ground and surface water posing potential risks due to U's chemical toxicity and radioactivity. This study investigates U sources and mobility at an iron ore mine site in Northern Sweden, where U concentrations (median 1.8 μg/l) exceeding the Swedish annual guideline value of 0.
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