An adsorbent technology that can selectively recover gold from wastewater using low-cost food material rice paper has been developed.
The National Research Foundation of Korea (NRF) said on the 15th that a research team led by Professor Lee Jeong-hyeon at Korea University developed an adsorbent that can recover gold ions contained in e-waste wastewater by modifying rice paper through a simple chemical treatment. The research findings were published online in May in the Proceedings of the National Academy of Sciences (PNAS).
Gold is a key resource used in various industries such as electronics and catalysts, but its reserves are limited. As a result, the need for technologies to recover gold from discarded electronic products or industrial wastewater is growing. Existing adsorbents often use large amounts of organic solvents and petroleum-based chemicals, or are in powder form, making them difficult to retrieve after use.
The research team focused on rice paper in film form, which does not require a separate molding process. They then chemically modified the starch-based rice paper under aqueous conditions using water to give it the ability to adsorb gold ions. The developed adsorbent maintained its shape stably even in water and increased adsorption efficiency through a porous structure.
The adsorbent selectively adsorbed gold ions over other metals in acidic e-waste wastewater. Some gold ions were reduced to gold nanoparticles during adsorption, and high-purity gold could then be recovered through a simple calcination process.
This study is meaningful in that it converted a low-cost biomass material into a material for resource recovery. The manufacturing process is relatively simple, suggesting potential applications in industrial wastewater treatment and e-waste resource recovery.
Professor Lee Jeong-hyeon said, "We developed a high value-added adsorbent through low-cost and eco-friendly biomass-based materials and processes," and added, "We will continue research on adsorbents for recovering precious metals and rare earth elements by utilizing various types of biomass."
References
PNAS (2026), DOI: https://doi.org/10.1073/pnas.2532984123