Solvent extraction studies of rhodium(III) by using n-octylaniline from malonate media: Analysis of synthetic mixtures and alloys

Herein, we have developed the solvent extraction method for the selective separation of precious rhodium(III). Various physicochemical parameters like pH, malonate concentration, n-octylaniline concentration, equilibrium time, aq: org phase ratio, and loading capacity of n-octylaniline are optimized for the quantitative recovery of the rhodium(III). The composition of the extracted species was determined by plotting the log-log graph of Log D [Rh(III)] vs. Log C [n-octylaniline] and Log D [Rh(III)] vs. Log C [malonate] ; the stoichiometry was found to be (metal: acid: extractant) 1:2:1. The proposed method was successfully applied for the separation of rhodium(III) from various binary and ternary mixtures of associated metal ions. The separation of the rhodium(III) from real samples was also carried out with the proposed method. The proposed method was applied for analysis of synthetic mixture corresponding to alloys such as pseudo-palladium, iron-rhodium alloy, platinum-rhodium alloy, and rhodium-platinum catalyst.