Abstract
This study addressed the growing challenge of electronic waste and the drawbacks of conventional hydrometallurgical processes, which often rely on hazardous reagents. It investigated a more sustainable approach for metal recovery from printed circuit boards (PCBs) by comparing three leaching systems: sulfuric acid (H₂SO₄), H₂SO₄–Fe₂(SO₄)₃, and H₂SO₄–(NH₄)₂S₂O₈. Using Response Surface Methodology to assess the effects of temperature (25–65 °C) and time (15–480 min), the ammonium persulfate system emerged as the most efficient. It achieved near-complete copper recovery (up to 100%), significantly surpassing the other systems. In contrast, silver recovery remained low (<35%) across all conditions, confirming its refractory behaviour within PCB material. Statistical analysis showed that dissolution time strongly influenced copper extraction, while temperature had minimal impact. Overall, the H₂SO₄–(NH₄)₂S₂O₈ system demonstrated high efficiency under mild conditions, highlighting its potential as a more environmentally friendly alternative to traditional leaching methods.