The increasing demand for neodymium (III) and samarium (III) due to their extensive high-tech applications has drawn much attention to their recovery. In this work, the copper-based metal-organic framework HKUST-1 was prepared and used for the adsorption of neodymium (III) and samarium (III) in the media of an aqueous solution. The maximum adsorption capacity of the material for neodymium (III) and samarium (III) was 284.11 and 503.45 mg g−1 at a pH of 5.5, respectively. The adsorption removal rate could achieve nearly 100% at the solid-to-liquid ratio of 1.0 g L−1, which is relatively excellent among such adsorbents used for rare earth elements uptake. The mechanism and reversibility of neodymium (III) and samarium (III) adsorption were systematically investigated by X-ray diffraction, Fourier transforms infrared spectroscopy, Raman spectra, and X-ray photoelectron spectroscopy, suggesting that the mechanism for the adsorption was ion exchange and complexation between trivalent rare-earth ions and the oxygen atom in the hydroxyl group. The reason behind the material displaying a more robust affinity for samarium (III) may be caused by the energy difference between fn and fn+1 states of samarium (III) was larger than that of neodymium (III), thus forming stronger covalent bonding. HKUST-1 exhibited high adsorption capacity towards Nd (III) and Sm (III). The reason behind the material displaying a more robust affinity for Sm(III) was caused by that the energy difference between fn and fn+1 states of Sm(III) was larger than that of Nd(III), thus forming stronger covalent bonding.

Hydroxyurea(HU) is a reducing and complexing agent that can be used in the PUREX process. Zr is an important fission product in the spent fuel and main element of concern in the nuclear fuel reprocessing. The decontamination of zirconium in the route of plutonium and uranium can be lowered by the complexation of hydroxyurea in the PUREX process. The complexation of Zr(Ⅳ) with hydroxyurea in the nitric acid system was investigated in this work. Under the condition of 0.3 mol/L HNO3, the complex ratio of Zr(Ⅳ) with HU is 1∶8 obtained by Job’s method. Combining with the half-integer method, the apparent stability constants of Zr(Ⅳ) with hydroxyurea are calculated as following: lg K1≈1.59, lg K2≈1.75, lg K3≈1.88, lg K4≈1.98, lg K5≈2.09, lg K6≈2.27, lg K7≈2.51, lg K8≈3.01. Under 1.0 mol/L HNO3, the complex ratio of Zr(Ⅳ) with hydroxyurea is 1∶4, and the apparent stability constants of Zr(Ⅳ) with hydroxyurea are lg K1≈2.33, lg K2≈2.51, lg K3≈2.78, lg K4≈3.31. Under 3.0 mol/L HNO3, the complex ratio of Zr(Ⅳ) with hydroxyurea is 1∶2, and the apparent stability constants of Zr(Ⅳ) with hydroxyurea are lg K1≈2.69 and lg K2≈2.79.

In this paper, the half-reaction time of the reaction between hydrazine and its derivatives with nitrous acid is measured using spectrophotometry and stopped-flow injection device. Using Gaussian09 and HyperChem, hydrazine and its derivatives have been structurally optimized and some quantization parameters are calculated. Combining the half-reaction time and the quantization parameters, and using statistical regression analysis, QSAR model of the reaction between hydrazine and its derivatives with nitrous acid is established. The results show that total energy of molecules is the most important influencing factor in the reaction, and the half-reaction time increases with total energy of the molecule except for allyl hydrazine, the reaction rate decreases with the increase of total energy of the molecule.

Hydroxysemicarbazide (HSC) as a novel salt-free organic reductant has the ability to accomplish the reduction of Pu(IV) fast in the nuclear fuel reprocessing. The radiolysis products of reductant varies along the absorbed does of aqueous solution suffered as a result of increasing fuel burn-up, which potentially imperil the separation process. Accordingly, it is necessary to determine the speciation and amount of radiolysis products of HSC in the media of nitric acid solution to lay the foundation for its later application. The experiment of HSC irradiated by α-ray in nitric acid aqueous solution was carried out and the yields speciation was analyzed in this paper. In addition, the G(HSC) and radiolysis products influenced by variation of radiation (α-ray, β-ray, γ-ray) was researched parallelly in our work.

The solvent extraction, complexing ability, and basicity of tetradentate N-donor 2,9-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-1,2,4-benzotriazin-3-yl)-1,10-phenanthroline (CyMe4-BT- Phen) and its derivatives functionalized by Br, hydroxyphenyl, nitryl were discussed and compared. It was demonstrated that four BTPhen ligands are able to selectively extract Am(lll) over Eu(lll). It was notable that the distribution ratio of 5-nitryl-CyMe4-BTPhen for Eu(lll) was suppressed under 0.02, which was much lower compared to DEu(lll) = 1 by CyMe4-BTPhen. The analysis of the effect of the substituent on the affinity to lanthanides was conducted by UV/vis and fluorescence spectroscopic titration. The stability constants of various ligands with Eu(lll) were obtained by fitting titration curve. Additionally, the basicity of various ligands was determined to be 3.1 ± 0.1, 2.3 ± 0.2, 0.9 ± 0.2, 0.5 ± 0.1 by NMR in the media of CD3OD with the addition of DClO4. The basicity of ligands follows the order of L1 > L2 > L3 > L4, indicating the tendency of protonation decreases with the electron-withdrawing ability increase.

The ammonium ions produced by the reactions of relatively excessive dimethylhydroxylamine(DMHAN) with Fe3+, Ce4+ and Pu4+ in dilute nitric acid solutions at room temperature were determined by ion chromatographic method. The results show that the reactions between DMHAN and Fe3+, Ce4+ and Pu4+ all produce a certain amount of ammonium ramifications under acidic conditions, which includes (CH3)2NH+2, NH+4 and CH3NH+3. The reaction mechanism is as follows. When DMHAN reacts with Fe3+, Ce4+ and Pu4+ respectively, it can be oxidized and reduced simultaneously in the acidic solution for the -1 valence of N atom in DMHAN. Then part of DMHAN is reduced to (CH3)2NH+2, and it is further converted into NH+4 and CH3NH+3 partly. With the increase of redox potential of Fe3+, Pu4+ and Ce4+, the conversion ratio of DMHAN into amine ions increases and the proportion of (CH3)2NH+2 in total amine ions decreases, while the proportion of NH+4 in total amine ions increases.