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采用动态激光光散射(DLS)、Fourier变换红外光谱(FTIR)、核磁共振波谱(31P-/1H NMR)等谱学技术,研究了TBP-Pd(Ⅱ)-HCl萃取有机相中微乳的形成以及溶液聚集态结构的变化。结果表明:(1)伴随钯的萃取,TBP萃取有机相中形成微乳。(2)萃取有机相中酸含量的变化导致溶液结构发生相应改变:胶团聚集体平均流体力学半径随有机相中酸含量的增加先增大而后又减小。微乳“内核水”的O—H伸缩振动吸收谱带逐渐宽化,与邻近的C—H伸缩振动区形成交迭,且有机相含酸量越高,交迭程度越大。水分子O—H—O弯曲变角振动吸收峰形也发生很大变化。TBP的PO伸缩振动明显向低频移动。核磁共振31P化学位移与活泼氢1H化学位移变化行为相反,说明TBP分子与酸和水分子发生缔合,形成RP=O.H+或RP=O.H3O+,并与PdCl42-存在相互作用。(3)有机相形成微乳水团后,由于大量H+的进入,微乳水团中酸浓度表现出明显的“增浓效应”。微乳水池内部微观环境的改变是导致钯萃取行为变化的主要原因。
The formation of microemulsion in organic phase of TBP-Pd (Ⅱ) -HCl was studied by dynamic laser light scattering (DLS), Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (31P- / 1H NMR) As well as the change of solution aggregation structure. The results showed that: (1) With the extraction of palladium, TBP extracted microemulsion in the organic phase. (2) The change of acid content in the extracted organic phase led to a corresponding change in the structure of the solution: the average hydrodynamic radius of the colloidal aggregates first increased and then decreased with the increase of the acid content in the organic phase. The O-H stretching vibration absorption band of the microemulsion “core water ” gradually widened and formed overlap with the adjacent C-H stretching vibration zone, and the higher the acid content in the organic phase, the greater the overlap. Water molecules O-H-O bending angle vibration absorption peak shape also changed a lot. The PO stretching vibrations of TBP clearly shift to low frequencies. Nuclear magnetic resonance 31P chemical shift and active hydrogen 1H chemical shift changes in the opposite behavior, indicating that TBP molecules and acid and water molecules associate to form RP = O.H + or RP = O.H3O +, and PdCl42- exist interaction. (3) After the organic phase formed the microemulsion water, the acid concentration in the microemulsion showed a “thickening effect” due to the entry of a large amount of H +. Micro-emulsion tank internal micro-environment changes lead to changes in palladium extraction behavior of the main reasons.