Vegetable oils of the kinds used in our daily cuisine contain organic fatty acids like linolenic and oleic acids.
| Photo Credit: Joyce Romero/Unsplash

In families across the world, silver is used as a precious metal, next to gold. Happy occasions in most families are celebrated with gold and silver garlands and rings. Silver is, of course, less expensive than gold.

But when it comes to use in industry and energy production, silver beats gold flat. 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). In addition, mobile phones used by about 1.4 billion people across India use silver for electricity conduction and storage. Each mobile phone uses 100-200 mg of silver. Likewise, a typical laptop computer uses 350 mg of silver, and we have about 50 million laptops in India.

If these are the numbers in India, one can imagine what the number across the world might be. It is estimated that about 7,275 metric tonnes of silver are used across the world for these purposes, but barely 15% is recuperated. And when a phone or a computer is damaged or discarded, the silver content is lost. If only we can get back this silver from these waste electrical and electronic equipment…

Clearly, silver plays a critical role in clean energy transition. Maria Smirnova writes in the 2025 ‘Sprott Silver Report’ that as more and more countries generate renewable power using solar panels, the demand for silver in the coming years will steadily increase. She points out that while some groups have considered using other metals (including lithium, cobalt, and nickel), it is still silver that plays a fundamental role in cleaner and greener energy production. And demand for silver is expected to increase by about 170% by the year. In addition, cars, buses and trains have started using solar power rather than petrol as fuel. Ms. Smirnova further points out that the International Energy Agency predicts that by 2035, every other car sold worldwide will be electric. That would mean the need for more silver.

It is against this background that a paper by Anze Zupanc, Prof. Timo Repo, and colleagues from Finland has come up with an efficient chemical method to recycle silver: using organic fatty acids, such as linolenic or oleic acids, which are found in seeds, nuts, and vegetable oils (such as olive oil or groundnut oil), which in turn are used in our daily cuisine.

Recovering silver from electronic waste is not simple: it may generate toxic substances from the use of strong acids and cyanide. Rather than use traditional methods of isolating silver from other metals and alloys, the group has come up with a method to separate and recover silver using the chemical method of using common unsaturated fatty acids, abundant in sunflower, groundnut, and other oils. The group found that these are recyclable and thus better than organic solvents and water media.

The researchers also found this method applicable to ‘urban mining’, where silver retrieval from waste electrical and electronic wastes (WEEE) from discarded computer motherboard pieces becomes possible. The research team concludes, “fatty acids may, therefore, become the next generation of media for treating precious multi-metal waste substrates”.