Nondestructive and Efficient Gold Recovery from Waste Mobile Phone Circuit Boards Using a H ₂ SO ₄ –H ₂ O ₂ –Glutamic Acid System

The rapidly growing volume of electronic waste, particularly waste printed circuit boards from mobile phones (WPCBs-MPs), demands sustainable recycling strategies to recover critical metals and advance circular economy goals. This study proposes a nondestructive hydrometallurgical method using a H2SO4–H2O2–glutamic acid ternary system, where the green ligand glutamic acid enables the selective stripping of gold from intact WPCBs-MPs. Systematic optimization via central composite design-response surface methodology enabled efficient gold recovery under optimized conditions (2.2 mol/L H2SO4, 0.758 mol/L H2O2, 0.085 mol/L glutamic acid, 313 K, 30 min), achieving an exceptional recovery efficiency of 99.23% and ultrahigh gold purity (>99.9%). Kinetic studies revealed a mixed control mechanism involving both diffusion and chemical reaction, with an activation energy of 25.8 kJ/mol. Scanning electron microscopy analysis confirmed effective base metal leaching and gold stripping while preserving the structural integrity of the boards and underlying copper circuits. This method avoids energy-intensive pulverization and offers a sustainable substitute for cyanide-based processes, thereby providing a technical basis for sustainable e-waste valorization, contributing to resource security and environmental protection throughout the electronics lifecycle.