Simultaneous leaching of Cu, Al, and Ni from computer printed circuit boards using Penicillium simplicissimum

Abstract A short lifespan and increased consumption patterns make e-waste the world's fastest-growing waste stream. Computers are one of the most significant parts of e-waste. Recycling of e-waste has been introduced as the main solution to deal with environmental problems and to save natural mines. This research aims to investigate the bioleaching of Cu, Ni, and Al from computer printed circuit boards (CPCBs) using Penicillium simplicissimum. The adaptation phase began at 1 g/l CPCBs powder with 107 spores and final pulp density was reached at 30 g/l. The most effective parameters including pulp density, initial pH, and the sucrose concentration were optimized to achieve maximum simultaneous leaching efficiency of Cu, Ni, and Al. The results showed the main mechanism of Al and Ni leaching was acidolysis, while complexoysis was the main mechanism for leaching of Cu. The optimal conditions of 60 g/l sucrose concentration, 16 g/l pulp density, and initial pH 6 led to leaching of 100% Cu, 70% Ni, and 98% Al. Additionally, the initial CPCBs sample and the bioleaching residue were analyzed using XRD, HPLC, SEM, and FTIR. The HPLC results confirmed that gluconic and oxalic acids were the main metabolites produced by P. simplicissimum. The SEM micrograph revealed the effectiveness of the bioleaching process in metal leaching. FTIR spectra validated conversion of the molecular structure to simpler materials, as well as the presence of HIPS, PC, and PPO in CPCBs waste powder.