American Chemical Society
Browse

Selective Palladium(II) Recovery Using a Polymer Inclusion Membrane with Tris(2-ethylhexyl) Phosphate (TEHP). Experimental and Theoretical Study

Download (126.6 kB)
journal contribution
posted on 2021-02-19, 13:03 authored by Minerva Monroy-Barreto, Ana Nelly Bautista-Flores, Nadia M. Munguia Acevedo, Eduardo Rodriguez de San Miguel, Josefina de Gyves
Extraction and recovery of palladium continues to be a technologically and economically challenging task, particularly in the recycling process of palladium from scrap automotive catalytic converters. In this work, extraction and transport of palladium­(II) from HCl media with and without KSCN in the feed and/or in the stripping solutions by tris­(2-ethylhexyl) phosphate (TEHP) and tris­(2-ethylhexyl) phosphate (TEHP)–triisobutylphosphine sulfide (CYANEX 471X) mixture were studied in two- (liquid and membrane extraction) or three-phase (polymer inclusion membrane, PIM) configurations. Regarding PIMs, the efficiency factors (permeability, selectivity, and stability) were determined. Numerical data analysis revealed that the transport of palladium is achieved by a complex mechanism in which the solvating effects of TEHP and TEHP–CYANEX 471X are coupled to chloride ion co-transport and thiocyanic acid counter-transport. Palladium recovery from a spent automotive catalytic converter was accomplished (approximately 90%) with excellent separation from Pt­(IV), Fe­(III), Al­(III), and other components via the studied membrane systems.

History