ABSTRACT
Crushed and ground printed circuit board (PCB) samples were characterized to evaluate copper, lead, and aluminum using X-ray fluorescence spectroscopy (XRF) and the morphology was done by scanning electron microscopy (SEM). The XRF characterizations showed 0.12% lead, 3.72% copper, and 12.73% aluminum in the PCBs. The metal solubilization experiments using Acidithiobacillus ferrooxidans indicated higher values of total metal solubilization when the initial pH of the inoculum was adjusted. However, these experiments did not show higher metal solubilization by bioleaching. The sequential bioremoval experiments using mixed culture after bioleaching assays with A. ferrooxidans with initial adjustment of inoculum pH and without applying a magnetic field removed 100% of Al, 27.34% of Cu, and 96.43% of Pb from the lixiviate medium; with magnetic field application, 100% of Al, 83.82% of Cu, and 98.27% of Pb were removed. A similar bioleaching experiment without inoculum pH adjustment and without field application achieved 99.74% removal for Cu and 91.92% for Pb. When the magnetic field was applied, 100% of Cu and 95.76% of Pb were removed. Bioreactors with a magnetic field do not show significantly better removal of any of the metals analyzed.
