Enhanced separation of Pd(II) and Pt(IV) from hydrochloric acid aqueous solution using 2-((2-methoxyethyl)thio)-1H-benzi
- PDF / 1,010,617 Bytes
- 10 Pages / 595.276 x 790.866 pts Page_size
- 19 Downloads / 196 Views
RARE METALS
ORIGINAL ARTICLE
Enhanced separation of Pd(II) and Pt(IV) from hydrochloric acid aqueous solution using 2-((2-methoxyethyl)thio)-1H-benzimidazole Shao-Ping Feng, Kun Huang*
Received: 29 March 2020 / Revised: 2 July 2020 / Accepted: 14 July 2020 Ó The Nonferrous Metals Society of China and Springer-Verlag GmbH Germany, part of Springer Nature 2020
Abstract Separation of palladium (Pd) and platinum (Pt) by solvent extraction is difficult because of their extremely similar physicochemical properties. Development of new extractants with a high extraction efficiency and excellent separation selectivity is the primary focus for enhancing the separation of Pd and Pt by solvent extraction. In this study, a new extractant, 2-((2-methoxyethyl)thio)-1H-benzimidazole (MOBI), which contains N, S, and O atoms, was synthesized and used to separate Pd(II) and Pt(IV) from a hydrochloric acid aqueous solution. The experimental results revealed that Pd(II) and Pt(IV) were effectively separated under the optimal conditions: MOBI concentration of 0.005 molL-1, HCl concentration of 0.2 molL-1, organic/aqueous (O/A) phase ratio of 1.0, and contact time of 15 min. The separation coefficient between Pd(II) and Pt(IV) was 1246.40, which indicates that MOBI has a higher selectivity for Pd(II) than Pt(IV). In addition, the mechanism of coordination between Pd(II) and MOBI was demonstrated through the slope method, Fourier transform infrared spectroscopy (FTIR), hydrogen-1 nuclear magnetic resonance spectroscopy (1H NMR), and carbon-13 nuclear magnetic resonance spectroscopy (13C NMR). The results revealed that MOBI could coordinate with Pd(II) via the N atom in the benzimidazole ring of MOBI molecules to form [Pd(MOBI)2Cl2](O).
S.-P. Feng, K. Huang* School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China e-mail: [email protected] S.-P. Feng Department of Chemistry, College of Science, Honghe University, Mengzi 661199, China
Keywords 2-((2-methoxyethyl)thio)-1H-benzimidazole; Palladium; Platinum; Extraction; Separation
1 Introduction Platinum group metals (PGMs) have wide applications, such as in catalytic agents, electronic industries, and metal alloys, due to their special physicochemical properties, which are irreplaceable in most applications [1, 2]. However, the limited resources and unlimited demand for PGMs in modern technologies have attracted considerable attention with regard to the recovery of PGMs from secondary resources and postconsumer scrap [3–5]. Separation and purification of PGMs possess similar chemical behavior and are therefore complicated processes [6, 7]. Palladium and platinum, which are two key members of PGMs, have applications such as in car catalysts, chemical synthesis, jewelry, space materials, and special devices [8, 9]. The wide application and limited resources require the recovery and purification of high purity palladium and platinum from either ores or secondary resources. Universally, palladium and platinum exist in the
Data Loading...
