N,N’-dimethyl-N,N’-dioctyl diglycolamide (DMDODGA) in 40/60 (V/V)% 1-octanol/kerosene was used to extract 14 lanthanides from nitric acid solution. The effects of the aqueous acidity, the DMDODGA concentration, and the temperature on the distribution ratio of Ln(III) were investigated. The extraction equilibrium constants K and the thermodynamic parameters were determined by the slope analysis method combined with Pitzer model. The IR spectra of the extracted species and pure extractant were recorded and analyzed. Moreover, 0.001 mol/L nitric acid is the suitable stripping agent, and the stripping efficiency of all lanthanides can reach up 90% by three times of stripping.

中文翻译：

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N,N'-二甲基-N,N'-二辛基二甘醇酰胺对硝酸介质中14种镧系元素的萃取剥离行为

N,N'-二甲基-N,N'-二辛基二甘醇酰胺 (DMDODGA) 的 40/60 (V/V)% 1-辛醇/煤油溶液用于从硝酸溶液中提取 14 种镧系元素。研究了水溶液酸度、DMDODGA 浓度和温度对 Ln(III) 分布比的影响。采用斜率分析法结合Pitzer模型确定萃取平衡常数K和热力学参数。记录和分析提取物和纯提取剂的红外光谱。此外，0.001 mol/L的硝酸是合适的反萃取剂，通过3倍的反萃取，所有镧系元素的反萃取效率可达90%。