Biossorção de ouro de soluções lixiviadas de microprocessadores de computador utilizando quitina

Abstract

The biosorption of gold from leached solutions of discarded computer microprocessors (DCM) was studied using chitin as biosorbent. Chitin and DCM were obtained and characterized. The DCM components were leached using thiourea solutions and, two ways were tested to recover gold from these solutions: (1) biosorption and (2) precipitation followed by biosorption. For each way, biosorption was evaluated by kinetic, equilibrium and thermodynamic aspects. For both ways, the general order model was suitable to represent the kinetic behavior and, the equilibrium was well represented by the BET model. The biosorption of gold on chitin was a spontaneous, favorable and exothermic process. It was found that the precipitation followed by biosorption was more efficient to recovery gold, since the other compounds were removed from the leached solution in the precipitation step. Using this way, about 80%of gold was recovered, using 20 g L 1 of chitin at 298 K for 4 h.