Uranium extraction from seawater is of strategic significance for nuclear power generation.Amidoximebased functional adsorbents play indispensable roles in the recovery of seawater uranium with high efficiency.Neverth...Uranium extraction from seawater is of strategic significance for nuclear power generation.Amidoximebased functional adsorbents play indispensable roles in the recovery of seawater uranium with high efficiency.Nevertheless,balancing the adsorption capacity and selectivity is challenging in the presence of complicated interfering ions especially vanadium.Herein,a polyarylether-based covalent organic framework functionalized with open-chain amidoxime(COF-HHTF-AO)was synthesized with remarkable chemical stability and excellent crystallinity.Impressively,the adsorption capacity of COF-HHTF-AO towards uranium in natural seawater reached up to 5.12 mg/g,which is 1.61 times higher than that for vanadium.Detailed computational calculations revealed that the higher selectivity for uranium over vanadium originated from the specific bonding nature and coordination pattern with amidoxime.Combining enhanced adsorption capacity,excellent selectivity and ultrahigh stability,COF-HHTF-AO serves as a promising adsorbent for uranium extraction from the natural seawater.展开更多
An amidoxime-based polymeric adsorbent was prepared by pre-irradiation grafting of acrylonitrile and acrylic acid onto high-density polyethylene fibers using electron beams,followed by amidoximation.Quantitative recov...An amidoxime-based polymeric adsorbent was prepared by pre-irradiation grafting of acrylonitrile and acrylic acid onto high-density polyethylene fibers using electron beams,followed by amidoximation.Quantitative recovery of uranium was investigated by flow-through experiment using simulated seawater and marine test in natural seawater.The maximum amount of uranium uptake was 2.51 mg/g-ads after 42 days of contact with simulated seawater and 0.13 mg/g-ads for 15 days of contact with natural seawater.A lower uranium uptake in marine test can be attributed to the short adsorption time and the contamination of marine microorganisms and iron.However,the high selectivity toward uranium against vanadium may be beneficial to harvest uranyl ion onto adsorbents and the economic feasibility for recovery of uranium from seawater.展开更多
The development of efficient materials for high extraction of uranium(UO22+) from seawater is critical for nuclear energy. Poly(amidoxime)-reduced graphene oxide(PAO/rGO) composites with excellent adsorption capabilit...The development of efficient materials for high extraction of uranium(UO22+) from seawater is critical for nuclear energy. Poly(amidoxime)-reduced graphene oxide(PAO/rGO) composites with excellent adsorption capability for UO22+ were synthesized by in situ polymerization of acrylonitrile monomers on GO surfaces, followed by amidoximation treatment with hydroxylamine. The adsorption capacities of PAO/rGO composites for UO22+ reached as high as 872 mg/g at pH 4.0. The excellent tolerance of these composites for high salinity and their regeneration-reuse properties can be applied in the nuclear-fuel industry by high extraction of trace UO22+ ions from seawater.展开更多
Uranyl （VI） amidoxime complexes are investigated using relativistic density functional theory. The equilibrium structures, bond orders, and Mulliken populations of the complexes have been systematically investigated...Uranyl （VI） amidoxime complexes are investigated using relativistic density functional theory. The equilibrium structures, bond orders, and Mulliken populations of the complexes have been systematically investigated under a generalized gradient approximation （GGA）. Comparison of （acet） uranyl amidoxime complexes （[UO2（AO）n]2-n, 1≤ n≤4） with available experimental data shows an excellent agreement. In addition, the U-O（1）, U-O（3）, C（1）-N（2）, and C（3） N（4） bond lengths of [UO2（CH3AO）4]2- are longer than experimental data by about 0.088, 0.05, 0.1, and 0.056 A. The angles of N（3） O（3）-U, O（2）-N（1）-C（1）, N（3）-C（3）-N（4）, N（4）-C（3） C（4）, and C（4）-C（3）-N（3） are different from each other, which is due to existing interaction between oxygen in uranyl and hydrogen in amino group. This interaction is found to be intra-molecular hydrogen bond. Studies on the bond orders, Mulliken charges, and Mulliken populations demonstrate that uranyl oxo group functions as hydrogen-bond acceptors and H atoms in ligands act as hydrogen-bond donors forming hydrogen bonds within the complex.展开更多
A novel amidoxime-based fibrous adsorbent,denoted as PE/PP-g-(PAAc-co-PAO), was prepared by preirradiation grafting of acrylic acid and acrylonitrile onto polyethylene-coated polypropylene skin-core(PE/PP)fibers using...A novel amidoxime-based fibrous adsorbent,denoted as PE/PP-g-(PAAc-co-PAO), was prepared by preirradiation grafting of acrylic acid and acrylonitrile onto polyethylene-coated polypropylene skin-core(PE/PP)fibers using 60 Co γ-ray irradiation, followed by amidoximation. The original and modified PE/PP fibers were characterized by a series of characterization methods to demonstrate the attachment of amidoxime groups onto the PE/PP fibers. Breaking strength tests confirmed that the fibrous adsorbent could maintain good mechanical properties. The adsorption capacity of the PE/PP-g-(PAAc-coPAO) fibers was investigated in simulated seawater with an initial uranium concentration of 330 μg/L. The uranium adsorption capacity was 2.27 mg/g-adsorbent after 24 h in simulated seawater, and the equilibrium data were well described by the Freundlich isotherm model. The PE/PP-g-(PAAc-co-PAO) adsorbent exhibited good regeneration and recyclability during five adsorption-desorption cycles.The adsorption test was also performed in simulated radioactive effluents with uranium concentrations of 10 and100 μg/L. The effect of the pH value on the adsorption capacity was also studied. At a very low initial concentration 10 μg/L solution, the PE/PP-g-(PAAc-co-PAO)fiber could remove as much as 93.0% of the uranium, and up to 71.2% of the uranium in the simulated radioactive effluent. These results indicated that the PE/PP-g-(PAAcco-PAO) adsorbent could be used in radioactive effluents over a wide range of pH values. Therefore, the PE/PP-g-(PAAc-co-PAO) fibers, with their high uranium selectivity,good regeneration and recyclability,good mechanical properties, and low cost, are promising adsorbents for extracting uranium from aqueous solutions.展开更多
基金supported by the Science Challenge Project(TZ2016004)the National Natural Key Research and Development Program of China(2018YFC1900105 and 2017YFA0207002)Beijing Outstanding Young Scientist Program。
文摘Uranium extraction from seawater is of strategic significance for nuclear power generation.Amidoximebased functional adsorbents play indispensable roles in the recovery of seawater uranium with high efficiency.Nevertheless,balancing the adsorption capacity and selectivity is challenging in the presence of complicated interfering ions especially vanadium.Herein,a polyarylether-based covalent organic framework functionalized with open-chain amidoxime(COF-HHTF-AO)was synthesized with remarkable chemical stability and excellent crystallinity.Impressively,the adsorption capacity of COF-HHTF-AO towards uranium in natural seawater reached up to 5.12 mg/g,which is 1.61 times higher than that for vanadium.Detailed computational calculations revealed that the higher selectivity for uranium over vanadium originated from the specific bonding nature and coordination pattern with amidoxime.Combining enhanced adsorption capacity,excellent selectivity and ultrahigh stability,COF-HHTF-AO serves as a promising adsorbent for uranium extraction from the natural seawater.
基金supported by the National Natural Science Foundation of China(Nos.21676291,21306220,11275252,11305243 and11405249)in part supported by the "Knowledge Innovation Program of Chinese academy of sciences"
文摘An amidoxime-based polymeric adsorbent was prepared by pre-irradiation grafting of acrylonitrile and acrylic acid onto high-density polyethylene fibers using electron beams,followed by amidoximation.Quantitative recovery of uranium was investigated by flow-through experiment using simulated seawater and marine test in natural seawater.The maximum amount of uranium uptake was 2.51 mg/g-ads after 42 days of contact with simulated seawater and 0.13 mg/g-ads for 15 days of contact with natural seawater.A lower uranium uptake in marine test can be attributed to the short adsorption time and the contamination of marine microorganisms and iron.However,the high selectivity toward uranium against vanadium may be beneficial to harvest uranyl ion onto adsorbents and the economic feasibility for recovery of uranium from seawater.
基金supported by the Chinese National Fusion Project for ITER(2013GB110005)the National Natural Science Foundation of China(91326202,21207136,21272236,21225730)+1 种基金the Priority Academic Program Development of Jiangsu Higher Education Institutions,the Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions,Hefei Center for Physical Science and Technology(2012FXZY005)the Science Foundation of Institute of Plasma Physics(DSJJ-13-YY01)
文摘The development of efficient materials for high extraction of uranium(UO22+) from seawater is critical for nuclear energy. Poly(amidoxime)-reduced graphene oxide(PAO/rGO) composites with excellent adsorption capability for UO22+ were synthesized by in situ polymerization of acrylonitrile monomers on GO surfaces, followed by amidoximation treatment with hydroxylamine. The adsorption capacities of PAO/rGO composites for UO22+ reached as high as 872 mg/g at pH 4.0. The excellent tolerance of these composites for high salinity and their regeneration-reuse properties can be applied in the nuclear-fuel industry by high extraction of trace UO22+ ions from seawater.
基金Project supported by the Science and Technology Development Foundation of China Academy of Engineering Physics （Grant No. 2011A0301003）.
文摘Uranyl （VI） amidoxime complexes are investigated using relativistic density functional theory. The equilibrium structures, bond orders, and Mulliken populations of the complexes have been systematically investigated under a generalized gradient approximation （GGA）. Comparison of （acet） uranyl amidoxime complexes （[UO2（AO）n]2-n, 1≤ n≤4） with available experimental data shows an excellent agreement. In addition, the U-O（1）, U-O（3）, C（1）-N（2）, and C（3） N（4） bond lengths of [UO2（CH3AO）4]2- are longer than experimental data by about 0.088, 0.05, 0.1, and 0.056 A. The angles of N（3） O（3）-U, O（2）-N（1）-C（1）, N（3）-C（3）-N（4）, N（4）-C（3） C（4）, and C（4）-C（3）-N（3） are different from each other, which is due to existing interaction between oxygen in uranyl and hydrogen in amino group. This interaction is found to be intra-molecular hydrogen bond. Studies on the bond orders, Mulliken charges, and Mulliken populations demonstrate that uranyl oxo group functions as hydrogen-bond acceptors and H atoms in ligands act as hydrogen-bond donors forming hydrogen bonds within the complex.
基金supported by the National Natural Science Foundation of China(Nos.U1732151 and 21676291)Strategic Pilot and Technology Special Funds of the Chinese Academy of Science(No.XDA02030200)
文摘A novel amidoxime-based fibrous adsorbent,denoted as PE/PP-g-(PAAc-co-PAO), was prepared by preirradiation grafting of acrylic acid and acrylonitrile onto polyethylene-coated polypropylene skin-core(PE/PP)fibers using 60 Co γ-ray irradiation, followed by amidoximation. The original and modified PE/PP fibers were characterized by a series of characterization methods to demonstrate the attachment of amidoxime groups onto the PE/PP fibers. Breaking strength tests confirmed that the fibrous adsorbent could maintain good mechanical properties. The adsorption capacity of the PE/PP-g-(PAAc-coPAO) fibers was investigated in simulated seawater with an initial uranium concentration of 330 μg/L. The uranium adsorption capacity was 2.27 mg/g-adsorbent after 24 h in simulated seawater, and the equilibrium data were well described by the Freundlich isotherm model. The PE/PP-g-(PAAc-co-PAO) adsorbent exhibited good regeneration and recyclability during five adsorption-desorption cycles.The adsorption test was also performed in simulated radioactive effluents with uranium concentrations of 10 and100 μg/L. The effect of the pH value on the adsorption capacity was also studied. At a very low initial concentration 10 μg/L solution, the PE/PP-g-(PAAc-co-PAO)fiber could remove as much as 93.0% of the uranium, and up to 71.2% of the uranium in the simulated radioactive effluent. These results indicated that the PE/PP-g-(PAAcco-PAO) adsorbent could be used in radioactive effluents over a wide range of pH values. Therefore, the PE/PP-g-(PAAc-co-PAO) fibers, with their high uranium selectivity,good regeneration and recyclability,good mechanical properties, and low cost, are promising adsorbents for extracting uranium from aqueous solutions.
