SORPTION-ATOMIC-ABSORPTION DETERMINATION OF PALLADIUM (II) IN AQUEOUS SOLUTIONS USING DITHIOOXAMIDATED POLYSILOXANE

Abstract

Polysiloxane modified with groups of rubeanic acid (dithiooxamidated polysiloxane (DTOAP)) is proposed for extraction of palladium (II) from the solution against the background of the accompanying components. Sorbent was synthesized for the first time at the Institute of Organic Synthesis (Ural Branch of the Russian Academy of Sciences) using «sol-gel» technique. Sorption of palladium (II) was carried out under competitive conditions with 9 possible accompanying metals ions present. Palladium (II) is quantitatively and selectively recovered under static conditions with DTOAP from a solution containing transition metal ions, including platinum (IV). It takes 30 minutes for complete extraction of palladium (II). Reversible character of palladium (II) sorption is shown. Quantitative desorption of metal ion from the sorbent surface is possible using a 1% solution of thiourea in 1 M hydrochloric acid. Sorption under dynamic conditions provides separation of palladium (II) from platinum (IV) and concomitant ions of base metals. DTOAP provides quantitative extraction of palladium (II) in an amount up to 0.2 mmol/g. The developed method of the atomic-absorption determination of palladium (II) with a preliminary concentration on a modified polysiloxane was tested in analysis of model and industrial solutions with a high saline background.