2-Octylaminopyridine assisted solvent extraction system for selective separation of palladium(ii) ion-pair complex from synthetic mixtures and real samples

Abstract

Herein, 2-octylaminopyridine (2-OAP) amine is used in the liquid-liquid extraction of palladium(II) from aqueous salicylate media. It is found that pH does not affect the metal extraction process in the pH range of 1.8-2.4. Palladium(II) complex formation was verified by a log-log plot, whereas from the slope analysis, the ion pair complex stoichiometry 1 : 1 (metal : ligand) and 1 : 3 (metal : acid) was confirmed. The extraction system was optimized for the choice of diluent (xylene) as well as for the effective stripping agent (5.0 M ammonia). The selectivity for palladium(II) was found to be maintained when the organic phase (0.03 M 2-OAP in xylene) is used to extract the palladium(II). The extraction saturation capacity of palladium(II) was determined from 0.02 M sodium salicylate solution with 10 mL 0.03 M 2-OAP, and its experimental value exceeds 2.5 mg under the experimental conditions. Stripping of palladium(II) from the loaded organic phase was performed with 5.0 M ammonia. The extraction with varying parameters like equilibrium time, temperature, diluents, concentration of extractant, loading capacity, regeneration power and stability of extraction was also studied. The extraction behavior of associated metals, namely, noble metals and base metals, has been investigated, and the conditions for binary separation involving these metal ions have been optimized. Based on the extraction protocol, palladium(II) has been recovered from real samples.

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.…”

Efficiency of 2-dodecylaminopyridine for the liquid-liquid extraction of gold(III) from succinic acid medium

“…In the extraction experiments, extractant 2-DDAP shows very good extractability for gold(III), plausible extraction mechanism discussed here for understanding the nature of ion pair complex of gold(III) in succinic acid media with 2-DDAP. The mechanism of ion pair complex was initiated through protonation of 2-DDAP to form cationic species, while anionic species was formed by combining succinic acid with gold(III) and both of these formed the ion pair complex as given [36].…”

Liquid- Liquid Extraction of Zinc(II) From Acid Media with N-N-Heptylaniline as an Extractant: Analysis of Pharmaceutical and Commercial Sample

“…An accurate, inexpensive and less laborious liquid-liquid extractive spectrophotometric procedure for the determination of zinc(II) in aqueous media has been developed [25]. Previously we have reported number of solvent extraction methods for the quantitative extraction of platinum group metals with amines [26][27][28][29][30][31][32][33][34][35][36][37][38][39]. In present research paper a systematic study of extraction of zinc(II) with N-n-heptylaniline in xylene has been carried out.…”