Kinetic study of the photocatalytic recovery of Pt from aqueous solution by TiO2, in a closed-loop reactor

The photocatalytic recovery of platinum PtCl62- ions from aqueous solution by TiO2 (anatase) at conditions met in hydrometallurgical practice (low platinum concentration, low pH values and high chloride concentration) was studied. A continuous flow system with recirculation of the TiO2 suspension through an illuminated column was applied. The addition of methanol as a "hole scavenger" was proved essential for the reaction to proceed. The influence of various parameters, such as initial platinum and methanol concentration, TiO2 concentration, pH and flow rate, on the recovery rate was studied. The rate determining stage was found to be the adsorption of methanol molecules on the particles surface. The process seems to be effective and recovery yields up to 95% were achieved. (C) 1908 Elsevier Science B.V.