Gold Recovery from Electronic Waste using Iodide-Iodine Leaching Solution and Nanobiochar Adsorbent

Hassanzadeh, Nafiseh; Sarkeshikian, Seyed Ali; Golboo, Mohammad Hossein; Safari, Soolmaz; Siadati, S. M. Hossein

doi:10.22034/ns.2025.2070101.1405

Gold Recovery from Electronic Waste using Iodide-Iodine Leaching Solution and Nanobiochar Adsorbent

Document Type : Original Article

Authors

Nafiseh Hassanzadeh

Seyed Ali Sarkeshikian

Mohammad Hossein Golboo

Soolmaz Safari

S. M. Hossein Siadati

Faculty of Materials Science and Engineering. K. N. Toosi University of Technology. Tehran. Iran

10.22034/ns.2025.2070101.1405

Abstract

The rapid increase in electronic waste has created significant environmental challenges. Recycling this waste, especially precious metals such as gold, is essential for reducing pollution and recovering valuable resources. This study aims to investigate iodide-iodine leaching as a cyanide-free process and to utilize nanobiochar as a cost-effective and environmentally friendly adsorbent for gold recovery. In this research, biochar derived from pruned apricot tree branches was used as a bio-based adsorbent for gold recovery. The effects of biochar particle size, temperature, and adsorption duration were optimized using Taguchi experimental design. Under optimal conditions (temperature of 70°C, adsorption time of 5 hours, and biochar particle size of 106–250 micrometers), the gold recovery efficiency using biochar reached 88%. Also, this method was compared with chemical precipitation and electrochemical precipitation. The combination of iodide-iodine leaching and the use of nano-biochar adsorbent, while providing acceptable efficiency, due to its low cost, ease of implementation, and environmental compatibility, can be a valuable option for gold recovery from electronic waste.

Keywords

Printed circuit boards

Gold recovery

Nanobiochar

Leaching

Taguchi design

Subjects