Behavior and mechanism investigation of separating Pt and Ir by liquid–liquid extraction using a mixed [C6bet]Br/[C6mim][NTF2] system. (26th July 2017)

• Record Type: Journal Article
• Authors: Yan, Yan; Wang, Qi; Xiang, Zeyang; Zheng, Yan; Wang, Shubin; Yang, Yanzhao
• Is Part Of: New journal of chemistry. Volume 41:Number 17(2017)
• Page Start: 8985
• Page End: 8992
• Publication Date: 2017-07-26
• Subjects: Chemistry -- Periodicals; Chimie -- Périodiques; 540
• DOI: 10.1039/c7nj02361h
• Languages: English
• ISSNs: 1144-0546

Abstract

Abstract : Separation of Pt(iv ) and Ir(iv ) was realized by selectively reducing Ir(iv ) to Ir(iii ) using NH2 OH·HCl. Abstract : In the process of recovering platinum group metals by extraction, separation of Pt and Ir is very difficult because Pt(iv ) and Ir(iv ) show similar chemical properties and extraction behaviours in hydrochloric acid medium. In this paper, a betaine-based ionic liquid [C6 bet]Br was firstly applied to the separation of Pt(iv ) and Ir(iv ). [C6 bet]Br showed remarkable precipitation performance of Pt(iv ) and Ir(iv ). The impactful extraction was realized by importing [C6 mim][NTF2 ] as the hydrophobic phase with extraction efficiencies of ca. 99% and 88% under optimal conditions. A selective reduction process for Ir(iv ) was firstly proposed for the separation of these two similar PGMs by using hydroxylamine hydrochloride (NH2 OH·HCl). The mechanism of extracting Pt(iv )/Ir(iv ) using [C6 bet]Br was confirmed to be an anion-exchange process by spectroscopic analysis (UV-Vis, FT-IR, 1 H NMR) and the method of continuous variation. The electrostatic potential map of [C6 bet]Br was calculated for the first time to confirm the anion-exchange mechanism. 8 M HCl was effective for the back extraction of Pt(iv ) and Ir(iv ).