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Insight into selective removal of copper from high-concentration nickel solutions with XPS and DFT: New technique to prepare 5N-nickel with chelating resin

Tao, Xuewen, Liu, Fuqiang, Bai, Zhiping, Wei, Dongyang, Zhang, Xiaopeng, Wang, Junfei, Gao, Jie, Sun, Xiaowen, Li, Baohua, Li, Chenghui, Li, Aimin
Journal of environmental sciences (China) 2016 v.48 pp. 34-44
X-radiation, X-ray photoelectron spectroscopy, active sites, adsorption, coordination compounds, copper, cost benefit analysis, metal ions, nickel, nitrogen, sorption isotherms
An efficient and profitable separation process was proposed to prepare 5N (the purity of the metal solution reaches 99.999%) high-purity nickel from 3N nickel-solutions using Purolite S984. The adsorption performance of this superior resin, especially its selectivity for metal ions, was explored quantitatively. The maximum adsorption capacity for copper was 2.286mmol/g calculated by the Langmuir model, which was twice as large as that for nickel. In the binary systems, the adsorption capacity for nickel was decreased by 45%, indicating direct competition for the active sites. The infinite separation factor for copper versus nickel exceeded 300, revealing the feasibility of preparing 5N-level high-purity nickel solutions, which was further verified using the 800BV (bed volume) effluent in the column dynamic process. According to the cost–benefit analysis, purification contributed to a profit of approximately 60,000USD per cycle, and the investment return period was less than 1/3years. Density functional theory analysis confirmed that four nitrogen atoms would be involved in the coordination complex and thus a structure involving two five-membered rings could be achieved. The X-ray photoelectron spectra confirmed the involvement of nitrogen atoms, implying a coordination ratio of approximately 1:1.