Metral54-100萃取分离铜、镍的密度泛函研究

DFT study on the extraction and separation of copper and nickel with Metral54-100

采用密度泛函理论DFT/B3LYP/6-31G+(d, p)方法计算不同配位形态的铜、镍萃合物的结合能、全局活性指数、局部活性指数和红外光谱,探讨了1-苯基-1,3癸二酮(Mextral54-100)萃取Cu(Ⅱ), Ni(Ⅱ)的行为及机理。结果表明,Mextral54-100对Cu(Ⅱ)的萃取能力大于Ni(Ⅱ)。在反萃过程中,铜的萃合物更易被反萃。萃合物羰基表现出最高的反应活性,为活性中心。萃合物中氨分子的取代数越多,萃合物构型近似于稳定的八面体结构。配体氨逐一被萃取剂的羰基取代,有效避免共萃氨。Mextral54-100从铜、镍氨混合溶液中萃取–反萃Cu(Ⅱ)和Ni(Ⅱ)的实验结果与理论预测结果吻合,进一步通过FT-IR证实了理论计算结果的准确性,密度泛函理论有望成为一种研究萃取分离性能的新方法。

In order to discuss the extraction and separation mechanism of copper and nickel by1-phennyl-1,3-sebacic-diketone(Mextral54-100) from ammonia solution, the binding energy, global activity indices, local activity indices and infrared spectrum(FT-IR) of copper complexes and nickel complexes were calculated bydensity functional theory DFT/B3 LYP/6-31 G+(d, p), based on quantum chemistry. The results showed that the extracting power of copper was beyond nickel with Mextral54-100. Global reactivity indexes pointed out that the order of the activity of the copper complexes was a>b>c, the order of the activity of the nickel complexes was d>e>f.The molecule frontal orbital analysis of the complexes indicated that the |Δε|(Δ ε = εHOMO-εLUMO) of a was|Δε|a=0.158, the |Δε| of d was |Δε|d=0.138, thus, the reaction activity of a was higher than that of d, and the copper complexes were easier than nickel complexes in the stripping process by the theoretical calculation results. Local activity indices showed out that the carbonyl exhibited the highest reactivity and was the active center. The more substitution number of ammonia molecules in the complexes, the stronger electron-donating ability of copper(Ⅱ) and nickel(Ⅱ), and the structure of the complex was similar to the stable octahedral structure. The ammonia molecules were replaced one by one by the carbonyl group in extractants, avoiding the co-extraction of ammonia effectively.The experimental results of extraction and stripping of copper and nickel from ammonia solution by Mextral54-100 were in good agreement with the theoretical calculation results by DFT, and which could be verified the accuracy of theoretical calculation results by FT-IR. What was more, DFT was expected a novel method to study the extraction and separation mechanism copper and nickel from ammonia solution in the future.