Extracting Gold from E-waste: A Sustainable and Cost-Effective Solution

A new composite material made from coconut fibers biochar modified with zero-valent iron (ZVI) has been shown to be effective for capturing gold from simulated e-waste leachate solutions.

February 3, 2024

1–2 minutes

Nguyen, Nguyen, et al (2024) Effective Adsorption of Gold from Electronic Waste by Acid LeachingLeaching is the process where nutrients are dissolved and carried away from the soil by water. This can lead to nutrient depletion and environmental pollution. Biochar can help reduce leaching by improving nutrient retention in the soil. More Solution Using Zero-Valent Iron Microparticles Modified–BiocharBiochar is a carbon-rich material created from biomass decomposition in low-oxygen conditions. It has important applications in environmental remediation, soil improvement, agriculture, carbon sequestration, energy storage, and sustainable materials, promoting efficiency and reducing waste in various contexts while addressing climate change challenges. More. Journal of Environmental Chemical Engineering. https://doi.org/10.1016/j.jece.2024.112063

Electronic waste, or e-waste, is a growing environmental problem, containing valuable metals like gold. However, recovering these metals using traditional methods can be expensive and harmful to the environment. This is where coconut fibers biochar (CFB) modified with zero-valent iron (ZVI), known as CFB@Fe, comes in as a promising solution.

CFB@Fe is a low-cost and eco-friendly composite material that can efficiently extract gold from acidic e-waste leachates. It offers several advantages over conventional methods:

Rapid gold adsorption: CFB@Fe can capture gold in just 5 minutes, making the process fast and efficient.
Wide pHpH is a measure of how acidic or alkaline a substance is. A pH of 7 is neutral, while lower pH values indicate acidity and higher values indicate alkalinity. Biochars are normally alkaline and can influence soil pH, often increasing it, which can be beneficial More range: Unlike other sorbents,CFB@Fe maintains high gold adsorption even at different pH levels,making it more versatile.
High adsorption capacity: CFB@Fe can hold more gold compared to other biochars, maximizing the recovery yield.
Selective sorption: CFB@Fe selectively targets gold, even in the presence of other metals, minimizing contamination.
Sustainable and cost-effective:CFB@Fe is made from recycled materials and requires minimal processing, making it an environmentally and economically attractive option.

The mechanism behind CFB@Fe’s effectiveness involves a combination of adsorption and reduction. The surface of CFB@Fe attracts gold ions, while the ZVI particles convert them into metallic gold. This process is efficient and leads to the deposition of pure gold on the sorbent.

Overall, CFB@Fe shows great potential for becoming a sustainable and cost-effective technology for gold recovery from e-waste. This research paves the way for developing more environmentally friendly methods for extracting valuable resources from electronic waste.