Optimization of metal bio-acid leaching from mobile phone printed circuit boards using natural organic acids and H2O2

With increased popularity and technological innovation, more and more electric and electronic equipment wastes (e-wastes) are being generated. Printed circuit boards (PCBs) as fundamental components of electronic wastes, consist of both precious and heavy metals. In this research, the simultaneous extraction Cu and Zn from PCBs used in mobile phones with a natural organic acid and H2O2 was examined. The organic acid was determined from agricultural lemon fruit. The leaching extraction factors investigated include lemon juice concentration, solid/liquid (S/L) ratio, and H2O2 concentration. Response surface methodology (RSM) was applied to optimize the extraction which resulted in the maximum recoveries of 89% Cu and 73% Zn at 1.41% (w/v) S/L ratio, 12.2% (v/v) H2O2, and 74% (v/v) lemon juice after 4 h at 20 degrees C. The effect of time on the Cu and Zn recoveries at the determined optimum condition was examined. Furthermore, a kinetic study based on a shrinking core model was performed and the result showed that mass diffusion was rate-limiting in the extraction. Graphic abstract