The efficient separation of amphoteric organic compounds from dilute solutions is of great importance in the industrial field. In the present work, the reactive extractions of 4-hydroxypyridine(4-HP) with tributyl pho...The efficient separation of amphoteric organic compounds from dilute solutions is of great importance in the industrial field. In the present work, the reactive extractions of 4-hydroxypyridine(4-HP) with tributyl phosphate(TBP), di(2-ethylhexyl) phosphoric acid(D2EHPA) and TBP + D2EHPA dissolved in 1-octanol were investigated, respectively. The influences of the initial concentrations of TBP, D2EHPA and TBP + D2EHPA on distribution ratio(D) were discussed, as well as the reactive extraction mechanism were proposed. The obvious intensification effect was observed when the mixture of TBP and D2EHPA was used as extractant. The best extraction conditions were found to be of the molar ratio of D2EHPA and TBP at 2:1 and the equilibrium aqueous pH at 3.50-4.50. D values increased with the increase of the total concentration of TBP and D2EHPA in 1-octanol. Especially, the analysis on the extraction mechanisms clearly indicate(i) TBP in 1-octanol shows negligible reactive extraction toward 4-HP,(ii) D2EHPA in 1-octanol exhibits moderate extraction effect by forming 4-HP:D2EHPA(1:1) and 4-HP:2D2EHPA(1:2) type complexes, while(iii) D2EHPA in TBP/1-octanol demonstrates the maximum distribution ratio with the 4-HP:D2EHPA(1:1) type complex domination. The discussion provides new insights on the mechanism and opens a new way for the intensified extraction of amphoteric organic compounds by using the mixture of multiple extractants in the diluent.展开更多
In order to clarify the mechanism and the complex formed in the extraction of divalent Mn by alkylphosphonic acid monoester, the solid complex has been prepared by mono (2-ethylhexyl)-2-ethylhexyl phosphate, HEH(EH)P,...In order to clarify the mechanism and the complex formed in the extraction of divalent Mn by alkylphosphonic acid monoester, the solid complex has been prepared by mono (2-ethylhexyl)-2-ethylhexyl phosphate, HEH(EH)P, HA with divalent Mn. The elemental analysis, magnetic susceptibility and thermogravimetry have been determined for the solid complex of HEH(EH)P-Mn(II) and the infrared spectrum has been carried out in comparison to the extractant HEH(EH)P. The extracted compound has also been studied by electronic and electron spin resonance spectroscopy in octane solvent and solid state at room temperature. On the basis of the measurements, it is concluded that the structure of the solid polymeric species MnA_2 is in a tetrahedral arrangement.展开更多
Metal ions including Fe^(3+),Ca^(2+),Mg^(2+),Ni^(2+),Co^(2+) and Cu^(2+) are commonly found in the leaching solution of laterite-nickel ores,and the pre-removal of Fe^(3+) is extremely important for the recovery of ni...Metal ions including Fe^(3+),Ca^(2+),Mg^(2+),Ni^(2+),Co^(2+) and Cu^(2+) are commonly found in the leaching solution of laterite-nickel ores,and the pre-removal of Fe^(3+) is extremely important for the recovery of nickel and cobalt.Di(2-ethylhexyl)phosphate acid(D2EHPA)showed high extraction rate and selectivity of Fe^(3+) over other metal ions.The acidity of the aqueous solution is crucial to the extraction of Fe^(3+),and the stoichiometry ratio between Fe^(3+) and the extractant is 0.86:1.54.The enthalpy for the extraction of Fe^(3+) using D2EHPA was 19.50 kJ/mol.The extraction of Fe^(3+)was ≥99% under the optimized conditions after a three-stage solvent extraction process.The iron stripping effects of different reagents showed an order of H_(2)C_(2)O_(4)>NH_(4)HCO_(3)>HCl>NaCl>NaHCO_(3)>Na_(2)SO_(3).The stripping of Fe was ≥99% under the optimized conditions using H_(2)C_(2)O_(4) as a stripping reagent.展开更多
基金supported by the Science and Technology Research Project of Henan Province (192102310490 and 212102310505)。
文摘The efficient separation of amphoteric organic compounds from dilute solutions is of great importance in the industrial field. In the present work, the reactive extractions of 4-hydroxypyridine(4-HP) with tributyl phosphate(TBP), di(2-ethylhexyl) phosphoric acid(D2EHPA) and TBP + D2EHPA dissolved in 1-octanol were investigated, respectively. The influences of the initial concentrations of TBP, D2EHPA and TBP + D2EHPA on distribution ratio(D) were discussed, as well as the reactive extraction mechanism were proposed. The obvious intensification effect was observed when the mixture of TBP and D2EHPA was used as extractant. The best extraction conditions were found to be of the molar ratio of D2EHPA and TBP at 2:1 and the equilibrium aqueous pH at 3.50-4.50. D values increased with the increase of the total concentration of TBP and D2EHPA in 1-octanol. Especially, the analysis on the extraction mechanisms clearly indicate(i) TBP in 1-octanol shows negligible reactive extraction toward 4-HP,(ii) D2EHPA in 1-octanol exhibits moderate extraction effect by forming 4-HP:D2EHPA(1:1) and 4-HP:2D2EHPA(1:2) type complexes, while(iii) D2EHPA in TBP/1-octanol demonstrates the maximum distribution ratio with the 4-HP:D2EHPA(1:1) type complex domination. The discussion provides new insights on the mechanism and opens a new way for the intensified extraction of amphoteric organic compounds by using the mixture of multiple extractants in the diluent.
文摘In order to clarify the mechanism and the complex formed in the extraction of divalent Mn by alkylphosphonic acid monoester, the solid complex has been prepared by mono (2-ethylhexyl)-2-ethylhexyl phosphate, HEH(EH)P, HA with divalent Mn. The elemental analysis, magnetic susceptibility and thermogravimetry have been determined for the solid complex of HEH(EH)P-Mn(II) and the infrared spectrum has been carried out in comparison to the extractant HEH(EH)P. The extracted compound has also been studied by electronic and electron spin resonance spectroscopy in octane solvent and solid state at room temperature. On the basis of the measurements, it is concluded that the structure of the solid polymeric species MnA_2 is in a tetrahedral arrangement.
基金financially supported by the National Key Research and Development Program of China(Grant No.018YFC1900502)Key Research Program of Frontier Sciences of Chinese Academy of Sciences(Grant No.QYZDJ-SSW-JSC021)+1 种基金the National Natural Science Foundation of China(Grant Nos.21606241,51804289 and 51774260)CAS Interdisciplinary Innovation Team.
文摘Metal ions including Fe^(3+),Ca^(2+),Mg^(2+),Ni^(2+),Co^(2+) and Cu^(2+) are commonly found in the leaching solution of laterite-nickel ores,and the pre-removal of Fe^(3+) is extremely important for the recovery of nickel and cobalt.Di(2-ethylhexyl)phosphate acid(D2EHPA)showed high extraction rate and selectivity of Fe^(3+) over other metal ions.The acidity of the aqueous solution is crucial to the extraction of Fe^(3+),and the stoichiometry ratio between Fe^(3+) and the extractant is 0.86:1.54.The enthalpy for the extraction of Fe^(3+) using D2EHPA was 19.50 kJ/mol.The extraction of Fe^(3+)was ≥99% under the optimized conditions after a three-stage solvent extraction process.The iron stripping effects of different reagents showed an order of H_(2)C_(2)O_(4)>NH_(4)HCO_(3)>HCl>NaCl>NaHCO_(3)>Na_(2)SO_(3).The stripping of Fe was ≥99% under the optimized conditions using H_(2)C_(2)O_(4) as a stripping reagent.
