Efficiency and Mechanism of Palladium(II) Extraction from Chloride Media with N-Hexadecylpiperidinium Chloride

Abstract

N-hexadecylpiperidinium chloride ([PIP16]Cl) has been synthesized and examined as a reagent for extractive recovery of palladium(II) from hydrochloric acid solutions. The effect of the contact time between the two phases, temperature and the concentration of palladium(II) ions, the extractant and HCl, were also evaluated. The anion-exchange mechanism of palladium(II) extraction with [PIP16]Cl was confirmed by Job's method, UV-VIS, IR and 1 H NMR analysis. The extraction of palladium(II) from 0.1 mol•L −1 HCl solution with [PIP16]Cl in toluene was very effective and amounted to almost 100%. Increases in both HCl and NaCl concentrations and increasing temperature had negative effects on the effectiveness of palladium(II) extraction. [PIP16]Cl also exhibited selectivity to extraction of palladium(II) over some other metals: rhodium(III), iron(III), aluminium(III), copper(II) and lead(II). From among the examined stripping solutions the most effective were 0.5 mol•L −1 aqueous solution of ammonia and 0.1 mol•L −1 thiourea in 0.1 or 1 mol•L −1 HCl. The percentage of palladium(II) stripped from loaded organic phase reached nearly 100%. The feasibility of regeneration of [PIP16]Cl and its reuse in subsequent extractions was also investigated.

Effective Transport Recovery of Palladium(II) from Hydrochloric Acid Solutions Using Polymer Inclusion Membrane with Tetrabutylammonium Bromide

“…The results suggest that the extraction of Pd(II) with TBAB proceeds according to the anion-exchange mechanism, similar to the extraction with Cyphos IL 104 [31,32], where the anionic group of the ionic liquid is re-placed by the chlorocomplex anion [28]. Cieszynska and Wieczorek [29] reported that palladium(II) is extracted from 0.1 mol•dm −3 HCl to the organic phase of the molar ratio of 1:2. Thus, it can be concluded that palladium(II) is extracted to the organic phase according to the following equation:…”

“…As can be seen, ionic liquids (ILs) are very often used as the carriers of metal ions for membrane synthesis [8][9][10][11][12][13][21][22][23][24] and as the extractants of PGMs [10,[26][27][28][29][30][31][32] in the conventional solvent extraction process. However, there have been no reports to date on palladium(II) transport using PIMs with TBAB.…”

New reagents for selective extraction of Pd(ii) and Au(iii) from acidic media

“…41 In contrast to “simple” amines used as extractants for Pd( ii ) whose effectiveness is weakly dependent on the acidity of the aqueous medium within a low pH range, 35,44 diamines capable of forming chelates with Pd( ii ) extract palladium most effectively at pH 1–2. 45,46…”

“…41 In contrast to ''simple'' amines used as extractants for Pd(II) whose effectiveness is weakly dependent on the acidity of the aqueous medium within a low pH range, 35,44 diamines capable of forming chelates with Pd(II) extract palladium most effectively at pH 1-2. 45,46 Therefore, the maximum efficiency of compound 6 at pH E 1 is natural. A decrease in the extraction efficiency of compound 6 at a pH o 1 may have a kinetic nature.…”

Pd(II) extraction from acid solutions by bis-(2-hidroxyl-5-alkylbenzyl)amine

“…The palladium-containing solutions used for extraction were prepared according to the procedure described in [13][14][15][16][17]. Separate solutions of bis-(2-hydroxyl-5-alkylbenzyl)amine in kerosene were used as extractants, followed by stirring an organic solution with an equal volume of 1 M NaOH, and then with water.…”