JOURNAL OF MOLECULAR STRUCTURE
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2020
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IF 2.463
Shaoping Feng,Kun Huang,Zhangjie Huang,Guiyang Liu,Guowei Zhang,Gaozhang Gou
ABSTRACT In view of the separation and recycling of Pd(II) from multi-metal aqueous solution, a functionalized extractant of 2-[(2-ethylhexyl)thio]benzoxazole (EHBXS) with excellent selectivity for Pd(II) was synthesized and used to extract Pd(II) for the first time. The effects of EHBXS concentration, HCl concentration, organic/aqueous (O/A) phase ratio, contact time, and regeneration of EHBXS were investigated in detail. The extraction efficiency of Pd(II) was almost 100 % while the co-extraction efficiencies of Pt(IV), Rh(III), Cu(II), Fe(III) and Ni(II) existed in the aqueous solution were less than 10 %, which indicates that EHBXS is an effective extractant and can effectively remove Pd(II) from other metals at desired extraction conditions. Thiourea ((NH 2 ) 2 CS) solution (1.0 mol/L) could be used as an effective Pd(II) stripping agent and the one-step stripping efficiency of Pd(II) was higher than 98 %. EHBXS has excellent regeneration ability and the extraction efficiency of Pd(II) with regenerated EHBXS reaches to 87% even after 7 cycles. Moreover, the coordination mechanism between EHBXS and Pd(II) has been proven via the slope method, FT-IR spectra, 1 H NMR, 13 C NMR and single X-ray diffraction. Pd(II) and EHBXS formed a 1:2 complex of Pd(EHBXS) 2 Cl 2 during extraction. Pd(II) was coordinated with two Cl atoms and two EHBXS, and thus formed Pd(EHBXS) 2 Cl 2 molecule, in which EHBXS was coordinated with Pd(II) via the N atom in the benzoxazole ring as neutral unidentate ligand.
研究领域:
化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2016
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IF 3.299
Yan Zheng,Liying Fang,Yan Yan,Shujie Lin,Zhaohui Liu,Yanzhao Yang
The silicone ionic liquid, 1-methyl-3-[tri-(trimethylsiloxy)]silylpropyl-imidazolium chloride ([Si 4 mim]Cl), was first used for the construction of the W/O microemulsion system and the [Si 4 mim]Cl/ n -heptane/ n -hexanol/NaCl microemulsion system was applied for palladium extraction for the first time. The stability of [Si 4 mim]Cl/ n -heptane/ n -hexanol/NaCl microemulsion system was characterized by the Turbiscan Lab. For the Pd (II) extraction by the [Si 4 mim]Cl/ n -heptane/ n -hexanol/NaCl microemulsion system, primary parameters (namely, the vibration time, the [Si 4 mim]Cl concentration, the phase ratio and the additives) affecting the palladium extraction was investigated to optimize the process. Under the optimum conditions, the extraction percentage of Pd (II) is up to 98%. Afterwards, the ionic-exchange mechanism of Pd (II) extraction by the [Si 4 mim]Cl/ n -heptane/ n -hexanol/NaCl microemulsion system was confirmed by the Job Method and analyzed by FT-IR spectra. The stripping of Pd (II) from the microemulsion phase was also studied using the NaCl solutions, indicating a high stripping efficiency. At last, the selectivity of the [Si 4 mim]Cl/ n -heptane/ n -hexanol/NaCl microemulsion system to Pd (II) from other metals (Cu (II), Co (II), Ni (II), Fe (III), Al (III) Zn (II), Ce (III), Li (I), Mg (II) and Sn (IV)) was demonstrated to be quite high. The results of our work indicate that the [Si 4 mim]Cl/ n -heptane/ n -hexanol/NaCl microemulsion system is a promising approach for Pd (II) extraction.
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
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2021
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IF 7.312
Qian Xiao,Lianjun Song,Xueyu Wang,Haowei Xu,Lanlan He,Qiuju Li,Songdong Ding
The solvent extraction of Pd 2+ in nitric acid solution by a phenanthroline-derived diamide ligand of N,N′ -diethyl- N,N′ -ditolyl-2,9-diamide-1,10-phenanthroline (Et-Tol-DAPhen) and the complexation between them were described. By using meta -nitrobenzotrifluoride (F-3) as a diluent, Et-Tol-DAPhen ligand extracted Pd 2+ with strong extractability and excellent selectivity in comparison with traditional amine extractants Aliquat 336 nitrate and tri- n -octylamine. Job's method and mole ratio method suggested the formation of a 1:1 complex of Pd 2+ with Et-Tol-DAPhen. The extraction was a spontaneous and exothermic process of decreased entropy. Furthermore, the analyses of Fourier transform infrared spectra (FT-IR), UV-vis titration, and single-crystal X-ray diffraction revealed that the composition of the extracted species was [Et-Tol-DAPhen·Pd(NO 3 ) 2 ]. Based on the results of solvent extraction and complexation study, a neutral complexation extraction model was proposed. Meanwhile, the stability constant for the complexation of Pd 2+ with Et-Tol-DAPhen was also presented.
研究领域:
化学
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
HYDROMETALLURGY
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2023
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IF 4.7
Shaoping Feng,Kun Huang
Dialkylsulfide is considered as the most promising extractant for separating Pd(II) and Pt(IV) in industrial processes. However, the slow kinetics for Pd(II) extraction limits its extensive application. The development of new extractants with faster kinetics, high extraction efficiency, and exceptional Pd(II) separation selectivity has been a persisting goal over the past few decades. In this study, a new functionalized extractant, 1-methyl-2-(nonylthio)-1H-imidazole (MNI) containing both N and S atoms, was synthesized and employed to separate Pd(II) from mixed hydrochloric acid solutions with different initial Pd(II)/Pt(IV) concentration ratios. Experimental results revealed that MNI not only has a high selectivity for Pd(II) over Pt(IV) but also has faster kinetics for Pd(II) extraction than diisopentylsulfide (S201) under similar extraction conditions. In contrast to traditional dialkylsulfide extractants, MNI coordinates with Pd(II) ions via the N(5) atom in its imidazole ring to form Pd(MNI) 2 Cl 2 complexes, instead of using the S atom as with dialkylsulfide. The extraction mechanism involving the coordination between Pd(II) and MNI was demonstrated using the slope analysis method and ultraviolet (UV), Fourier-transform infrared (FT-IR), 1 H NMR, and 13 C NMR spectroscopic methods. The fast extraction kinetics between MNI and Pd(II) was possibly attributed to the high charge density of the N(5) atom in the imidazole ring, whereas the outstanding separation selectivity for Pd(II) was due to the strong affinity of the N(5) atom. The facile synthesis, high saturation capacity, excellent Pd(II) selectivity, and remarkable reusability endow MNI with potential applications in Pd(II) recovery from leach solutions of waste automotive catalysts and other secondary resources.
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
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