The Development of Palladium(II)-Specific Amine-Functionalized Silica-Based Microparticles: Adsorption and Column Separation Studies

• Published in: Separation science and technology Vol. 50; no. 10; pp. 1497 - 1506
• Main Authors: Fayemi, Omolola E., Ogunlaja, Adeniyi S., Antunes, Edith, Nyokong, Tebello, Tshentu, Zenixole R.
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 03.07.2015
• Subjects: amine functionalized silica; palladium(II)-specific; platinum group metals; separation
• ISSN: 0149-6395; 1520-5754
• DOI: 10.1080/01496395.2014.978017

The adsorption and separation of platinum(IV) and palladium(II) chlorido species ([PtCl 6 ] 2− and [PdCl 4 ] 2− ) on silica-based microparticles functionalized with ammonium centers based on ethylenediamine (EDA), diethylenetriamine (DETA), triethylenetriamine (TETA) and tris-(2-aminoethyl)amine (TAEA) were investigated. The functionalized sorbent materials were characterized using SEM, XPS, BET, and FTIR. The sorbents were used in the batch and column study for adsorption and selective separation of [PtCl 6 2− and PdCl 4 ] 2− . The adsorption model for both [PtCl 6 ] 2− and [PdCl 4 ] 2− on the different sorbent materials fitted the Freundlich isotherm with R 2 values > 0.99. The S-TETA sorbent material was palladium(II) specific. Pd(II) loaded on the silica column was recovered using 3% m/v thiourea solution as the eluting agent. Separation of platinum and palladium was achieved by selective stripping of [PtCl 6 ] 2− with 0.5 M of NaClO 4 in 1.0 M HCl while Pd(II) was eluted with 0.5 M thiourea in 1.0 M HCl. The separation of palladium (Pd) from a mixture containing platinum (Pt), iridium (Ir), and rhodium (Rh) was successful on silica functionalized with triethylenetriamine (TETA) showing specificity for palladium(II) and a loading capacity of 0.27 mg/g. S-TETA showed potential for use in the recovery of palladium from platinum group metals such as from solutions of worn out automobile emission control catalytic convertors and other secondary sources.