Concentration of Platinum(IV) From Acidic Chloride and Sulfate–Chloride Aqueous Media With Reversed Micellar Solutions of Oxyethylated Surfactant

Abstract

The possibility of employing reversed micelles of oxyethylated surfactants to concentrate platinum from acidic aqueous media was investigated. A procedure for reversed micellar concentration is described. Platinum concentration was effected by means of desolubilization in a non-traditional back-extraction stage by dilution of the reversed micellar solution with chloroform or a mixture of chloroform with hexane. In acidic sulfate–chloride media the distribution ratio of Pt ^IV increased to about 10 ² –5 × 10 ³ in the presence of Br ^- and I ^- as complexing agents. In chloride media the distribution ratio could be increased to about 2 × 10 ³ by using SnCl ₂ . The maximum recovery of platinum from the extract did not exceed 85%. With I ^- as a complexing agent, no back-extraction could be performed. With this back-extraction procedure, the Pt ^IV concentration factor varied from about 10 ² to 10 ³ depending on the aqueous feed composition. It was shown spectrophotometrically that Pt ^IV complex species were the same in the feed, extract and desolubilized aqueous solution. The possibility of the spectrophotometric determination of platinum with SnCl ₂ directly in the reversed micellar solution is demonstrated.