Extraction of platinum and palladium from aqueous solutions using ionic-liquid-modified magnetic nanoparticles

• Published in: Journal of water process engineering Vol. 63; p. 105510
• Main Authors: Almeida, Joana C., Cardoso, Celso E.D., Neves, Márcia C., Trindade, Tito, Freire, Mara G., Pereira, Eduarda
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.06.2024
• Subjects: Box-Behnken design; Ionic liquids; Magnetic nanoparticles; Platinum group elements; Sorption; Sorption; Ionic liquids; Box-Behnken design; Platinum group elements; Magnetic nanoparticles
• ISSN: 2214-7144; 2214-7144
• DOI: 10.1016/j.jwpe.2024.105510

Platinum (Pt) and palladium (Pd) are noble metals with a high economic and strategic value in several technologies, including catalytic converters production. This work focused on the impact of three key variables on the performance of ionic liquid (IL)-modified magnetite nanoparticles (NPs) in removing Pt(IV) and Pd(II) from aqueous solutions, in which the optimal operational conditions were identified through a Response Surface Methodology (RSM). Experimental conditions were defined by a Box-Behnken Design of 3 factors-3 levels (pH of 4, 6 and 8; sorbent dose of 100, 300 and 500 mg/L; and element concentration of 0.4, 1.2 and 2.0 mg/L). The results have shown high capacity of IL-based NPs to remove Pd. The optimal conditions leading to the total removal of Pd(II) have been found as: 1 h of sorption, pH 6.34–6.77, 391–418 mg/L of sorbent, and 1.2–1.7 mg/L of platinum-group elements (PGEs). The optimal operating conditions obtained by RSM were then tested on more complex matrices, such as bottled water and sea water with salinity 15. It was found that NPs have a high potential in removing Pd(II) from bottled water; however, in solutions with salinity 15, the efficiency decreases significantly due to competition between Pd(II) and other ions present in solution. [Display omitted] •Magnetic nanosorbents functionalized with ILs were successfully prepared.•Pt and Pd extraction by IL-modified magnetic NPs was optimized by RSM.•The 3 factors studied were pH, dose of sorbent and PGEs initial concentration.•NPs reached 90 % of Pd removal from ultra-pure water in just 1 h.•The most influencing factor for Pd removal was pH, maximized at pH 6.5.