Separation and Recovery of Platinum and Palladium from Spent Petrochemical Catalysts Using Activated Carbon, Analysis of Two Kind of Most Used Catalysts in Petro Chemistry

Abstract

The goal of this work is the separation and recovery of platinum and palladium from spent catalyst. The recovery consisted of separating the maximum amount of platinum and palladium from catalysts and changing them into usable forms. The petroleum and petrochemical units use Pt and Pd catalyst for reactions such as reforming and hydrogenation. Because these materials contain valuable metals, such as Pt and Pd, these metals should be recycled. Based on economic reasons and the high price of new catalysts, petrochemical companies should solve this problem. The new method in this work may help to recover these metals from spent catalyst. This method may help solve several environmental problems. In this work, the recovery of platinum and palladium from petroleum catalysts has been studied using spent catalysts. Two catalysts were characterized by XRF, XRD, and AAS. Aqua regia, used as a leaching agent, and the effect of dissolution temperature and time, Liquid/Solid (L/S) ratio, size of particles, and elimination of coke were also investigated. Under optimized conditions, the leaching process was done with 98% efficiency. Recovery of platinum and palladium from the leached solutions was done by the adsorption process with Activated Carbon (AC) in an environmentally friendly manner. According to the results, the optimum operating conditions for platinum and palladium removal by activated carbon were a temperature of a solution of 85 and 98℃, pH = 0.5 and 2, time of adsorption 180 and 150 min and adsorbent loading capacity = 18.75 mgPt/gAC and 12.5 mgPd/gAC, respectively. The activated carbon containing platinum and palladium was decomposed by ignition to produce platinum and palladium powder with commercial purity of 96.5% and 96.3% respectively.