Context: Scientists have developed a groundbreaking technique to recover silver from electronic waste using organic fatty acids found in cooking oils. This offers a safer, cost-effective, and environmentally friendly alternative to traditional chemical recycling processes.
Relevance of the Topic: Prelims: Key facts about Silver; Applications of Silver in the clean energy transition.
Cooking oils can help recover Silver from e-waste
- Traditional silver recovery methods involve toxic chemicals like cyanide and strong acids, which are highly toxic, corrosive and harmful to the environment.
- The newly discovered method uses natural fatty acids (like those in sunflower or olive oil) to recover silver from electronic waste without releasing harmful toxins.
- To dissolve silver, the most commonly used unsaturated fatty acids- oleic, linoleic and linolenic- were combined with an aqueous hydrogen peroxide (30%) solution as a green oxidant under mild conditions. This combination effectively dissolved silver into the fatty acids. This dissolved silver can be later recovered.
- Utility: The method can be applicable to urban mining, to retrieve silver from waste electrical and electronic wastes (WEEE) from discarded computer motherboard pieces.
Need for better recycling methods:
- Silver is used to capture sunlight through rooftop solar panels across India, generating about 108 GW of clean and green electricity yearly across the nation (about 10% of what is generated from coal). Silver is also used in Mobile phones and laptops.
- It is estimated that about 7,275 metric tonnes of silver are used across the world for these purposes, but barely 15% is recovered (When a phone or a computer is damaged or discarded, the silver content is lost).
- With the global shift toward renewable energy and electric vehicles, the demand for silver is expected to rise by 170% by 2020. This calls for better recycling methods.
The research team concludes that fatty acids may become the next generation of solvents for treating precious multi-metal waste substrates.