EXTRACTION AND RECOVERY OF PALLADIUM AND PLATINUM ACROSS HOLLOW FIBER SUPPORTED LIQUID MEMBRANE

Abstract

The extraction and stripping of palladium from flexible printed circuit board (FPCB) wastewater, and platinum from gold refining (GR) wastewater via hollow fiber supported liquid membrane were studied. In case of the separation of palladium, the extraction and stripping reached 96% and 91%, respectively by using 5%(v/v) LIX84-I dissolved in kerosene. Other conditions were feed solution at pH 2, stripping solution consisting of 0.8 M thiourea and 1 M hydrochloric acid, and flow rates of feed and stripping solutions at 100 ml/min. For the extraction of platinum, 96% extraction and 88% stripping were obtained by using 10%(v/v) Aliquat 336 dissolved in kerosene while other operating conditions were similar to the separation of palladium from FPCB wastewater. The separation factor of platinum in GR wastewater from palladium, gold, copper and zinc ions were approximately 17, 249, 970 and 1276, respectively. Additionally, natural solvents, i.e., sunflower oil, coconut oil and soybean oil were used instead of kerosene in the separation of platinum from GR wastewater. It was found that sunflower oil gave the highest platinum extraction, however, only 65% was attained compared with kerosene. In addition, the estimated mass transfer results of the extraction of palladium by the mathematical model based on diffusion, the reaction at the interface of feed and liquid membrane phases, and the accumulation of the metal ions in liquid membrane phase were obtained. The deviation from the experimental results was lower than 5%.