New development of inorganic ion exchanger: Selective Uptake of Palladium by Insoluble Ferrocyanides

Abstract

The selective uptake properties of Pd2+ions on different insoluble ferrocyanides (KNiFC, KCuFC, KCoFC, KFeFC and KZnFC) have been studied by the batch method. The particle size was estimated to be about 50 nm and the fine particles formed larger aggregates. The uptake rate of Pd2+ on KNiFC was fairly fast and the uptake equilibrium was attained within 1 h. A relatively large Kd value above 105 cm3 g-1 was obtained in the presence of HNO3 up to 7 M and the maximum Kd values above 105 cm3 g-1 were obtained in the temperature range of 30 to 50°C. The uptake of Pd2+ follows a Langmuir-type adsorption equation and the maximum uptake amount on KCuFC was estimated to be 2.07 mmol g-1. The Pd2+ions were incorporated into the products mainly by the ion exchange of 2K+ _??_Pd2+. The insoluble ferrocyanides were thus favourable adsorbents for the selective separation of Pd2+ ions from high-level liquid wastes.