The rapid increase in the use of electronic devices such as smartphones and laptops has driven a sharp rise in global electronic waste (e-waste) generation. According to an international report, worldwide e-waste generation reached approximately 53 million tons in 2020 and is projected to increase to 74 million tons by 2030.

Waste printed circuit boards (PCBs), the core components of electronic devices, contain precious metals such as gold and silver and are therefore referred to as 'urban mines.' However, because of their complex metal compositions and the need for harsh chemical treatments, selectively separating and recovering only gold has been limited in practical industrial settings.

A joint research team led by Jeonbuk National University (JBNU) Professor Yun Yeong-sang and Gyeongsang National University Professor Won Seong-uk has developed a high-performance adsorption membrane capable of selectively extracting gold even in strongly acidic environments, addressing these limitations. The research results were published in the latest issue of the Chemical Engineering Journal, a leading journal in the field of chemical engineering.

The membrane developed by the team has a structure in which a polymer bearing amine functional groups is stably bound to a plastic-based membrane. It binds strongly to gold ions, allowing it to preferentially adsorb gold over other metals such as copper and nickel. In experiments, the membrane adsorbed approximately 720–870 mg of gold per gram, achieving world-class performance, and maintained stable adsorption performance even in strongly acidic environments.

Notably, once gold ions are adsorbed onto the membrane, they are naturally reduced to the metallic state without the need for a separate reducing agent or additional chemicals. Unlike conventional methods, the used membrane can be burned without strong acid treatment or high-temperature processes, leaving only high-purity gold. The research team explained, 'The greatest advantage is that the process can be drastically simplified while greatly reducing environmental burden.'

Additionally, the membrane showed almost no performance degradation after at least three repeated uses, and it successfully and selectively recovered gold in a continuous process using actual waste printed circuit board solutions, demonstrating its potential for industrial application.

Professor Yun Yeong-sang said, 'An era in which cities become mines is coming. Circular economy technologies that recover resources from discarded electronic devices will determine future industrial competitiveness.' Professor Won Seong-uk, a former student of Professor Yun, stated that he is currently conducting pilot demonstrations of the technology at the start-up company Eptlus Co., Ltd., in which he participates, and added, 'We plan to expand the application of the technology to various industrial wastes, such as battery waste.'

Meanwhile, this research is being evaluated as a key technology that could accelerate the commercialization of the e-waste recycling industry, and is expected to offer an alternative that can simultaneously improve the environmental and economic performance of precious metal recovery technologies.