U(VI) and Th(IV) recovery using silica beads functionalized with urea- or thiourea-based polymers - Application to ore leachate.

Autor: Hamza MF; School of Nuclear Science and Technology, University of South China, Heng Yang 421001, China; Nuclear Materials Authority, POB 530, El-Maadi, Cairo, Egypt. Electronic address: m_fouda21@hotmail.com., Wei Y; School of Nuclear Science and Technology, University of South China, Heng Yang 421001, China; School of Nuclear Science and Engineering, Shanghai Jiao Tong University, Shanghai, China. Electronic address: yzwei@sjtu.edu.cn., Khalafalla MS; Nuclear Materials Authority, POB 530, El-Maadi, Cairo, Egypt. Electronic address: mahmoudsayed24@yahoo.com., Abed NS; Nuclear Materials Authority, POB 530, El-Maadi, Cairo, Egypt. Electronic address: nova848@yahoo.com., Fouda A; Botany and Microbiology Department, Faculty of Science, Al-Azhar University, Nasr City, Cairo 11884, Egypt. Electronic address: amr_fh83@azhar.edu.eg., Elwakeel KZ; University of Jeddah, College of Science, Department of Chemistry, Jeddah, Saudi Arabia; Environmental Science Department, Faculty of Science, Port-Said University, Port-Said, Egypt. Electronic address: kelwkeel@uj.edu.sa., Guibal E; Polymers Composites and Hybrids (PCH), IMT Mines Ales, Alès, France. Electronic address: eric.guibal@mines-ales.fr., Hamad NA; Faculty of Science, Menoufia University, Shebine El-Koam, Egypt. Electronic address: nhamad059@gmail.com.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2022 May 15; Vol. 821, pp. 153184. Date of Electronic Publication: 2022 Jan 18.
DOI: 10.1016/j.scitotenv.2022.153184
Abstrakt: Urea and thiourea have been successfully deposited at the surface of silica beads (through one-pot reaction with formaldehyde) for designing new sorbents for U(VI) and Th(IV) recovery (UR/SiO 2 and TUR/SiO 2 composites, respectively). These materials have been characterized by FTIR, titration, elemental analysis, BET, TGA, SEM-EDX for identification of structural and chemical properties, and interpretation of binding mechanisms. Based on deprotonation of reactive groups (amine, carbonyl, or thiocarbonyl) and metal speciation, the optimum pH was ~4. Uptake kinetics was fast (equilibrium within 60-90 min). Although the kinetic profiles are fitted by the pseudo-first order rate equation, the resistance to intraparticle diffusion cannot be neglected. Sorption isotherms were fitted by Langmuir equation (maximum sorption capacities: 1-1.2 mmol g -1 ). Thermodynamics are also investigated showing differences between the two types of functionalized groups: exothermic for TUR/SiO 2 and endothermic for UR/SiO 2 . Metal desorption is highly effective using 0.3-0.5 M HCl solutions: total desorption occurs within 30-60 min; sorption/desorption properties are remarkably stable for at least 5 cycles. The sorbents have marked preference for U(VI) and Th(IV) over alkali-earth and base metals at pH eq ~4.8. By preliminary precipitation steps, it is possible "cleaning" ore leachates of pegmatite ore, and recovering U(VI) and Th(IV) using functionalized silica beads. After elution and selective recovery by precipitation with oxalate (Th-cake) and alkaline (U-cake), the metals can be valorized.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2022. Published by Elsevier B.V.)
Databáze: MEDLINE
Externí odkaz: