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 solu tion by TiO2 (anatase) at conditions met in hydrometallurgical practic e (low platinum concentration, low pH values and high chloride concent ration) was studied. A continuous flow system with recirculation of th e TiO2 suspension through an illuminated column was applied. The addit ion of methanol as a ''hole scavenger'' was proved essential for the r eaction to proceed. The influence of various parameters, such as initi al platinum and methanol concentration, TiO2 concentration, pH and flo w rate, on the recovery rate was studied. The rate determining stage w as found to be the adsorption of methanol molecules on the particles s urface. The process seems to be effective and recovery yields up to 95 % were achieved. (C) 1908 Elsevier Science B.V.