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Updated: Jan 30, 2026
13:42
Gold Nanoparticle Synthesis
Published on: July 10, 2021
15.9K
Thiourea bioleaching for gold recycling from e-waste
Intan Nurul Rizki1, Yu Tanaka1, Naoko Okibe1
1Department of Earth Resources Engineering, Faculty of Engineering, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan.
Waste Management (New York, N.Y.)
|January 30, 2019
Summary
This study introduces microbiologically-mediated thiourea leaching (TU-bioleaching) for gold recovery from electronic wastes. It achieves 98% gold dissolution using low reagent concentrations and microbial control, offering an eco-friendly alternative to cyanidation.
Area of Science:
- * Environmental Science & Engineering
- * Biotechnology & Bioengineering
- * Materials Science & Metallurgy
Background:
- * Electronic waste (e-waste) recycling is crucial for metal recovery and environmental protection.
- * Thiourea leaching offers a less toxic alternative to cyanidation for gold (Au) extraction from e-wastes.
- * Microbiological approaches for precious metal recovery are underexplored, particularly for reducing reagent consumption.
Purpose of the Study:
- * To investigate the potential of microbiologically-mediated thiourea leaching (TU-bioleaching) for gold recovery from e-wastes.
- * To optimize reagent consumption and facilitate gold dissolution.
- * To explore the role of microbial iron oxidation in enhancing the process.
Main Methods:
- * Screening of Fe-oxidizing bacteria/archaea for thiourea tolerance and efficacy.
- * Optimization of the thiourea to Fe3+ ratio to control redox potential (Eh).
- * Assessing gold dissolution from Printed Circuit Boards (PCBs) under microbial Eh control.
Main Results:
- * Acidiplasma sp. Fv-Ap showed robust Fe-oxidation in the presence of thiourea and PCBs.
- * Optimized microbial Eh control (490-545 mV) enabled 98% gold dissolution.
- * Achieved high gold recovery using low concentrations (1 mM Fe3+, 10 mM thiourea).
Conclusions:
- * Microbiologically-mediated TU-bioleaching is a viable and efficient method for gold recycling from e-wastes.
- * This process significantly reduces reagent consumption and environmental hazards compared to traditional methods.
- * The study presents a novel, eco-friendly approach for sustainable precious metal recovery.
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