Chennai: Researchers at IIT Madras developed a sustainable method to recover valuable metals from electronic waste using environment-friendly solvents derived from natural compounds.The researchers explored the use of deep eutectic solvents, which are liquid mixtures made from biodegradable natural substances capable of dissolving metals without harming the environment.They developed a green solvent using thymol, derived from thyme, and capric acid, which effectively dissolved copper metal. The dissolved copper was extracted using trisodium citrate, a non-toxic chemical, and subsequently used to synthesise copper nanoparticles with industrial and technological applications.By adjusting the pH of the solution, the team produced different forms of copper, including copper oxide nanoparticles and pure copper metal. The method was also successfully extended to recover iron from real e-waste samples such as printed circuit boards and copper sheets.“Unlike conventional acid-based extraction techniques, this method is non-toxic, and water-efficient, generating no hazardous waste. Its ability to recover multiple metals and directly produce valuable nanomaterials makes it more versatile and sustainable than other existing approaches,” said Prof S Pushpavanam, department of chemical engineering.The research was conducted by Prof Ranjit Bauri from the department of metallurgical and materials engineering, along with Prof Pushpavanam and Sinu Kurian, a PhD research scholar jointly affiliated with both departments. The findings were published in The Journal of Sustainable Metallurgy.E-waste is one of the fastest-growing waste streams globally and contains recoverable metals such as copper, gold, and iron. Researchers said the method offers an alternative to conventional e-waste recycling processes that rely on harsh chemicals, generate toxic effluents, and often yield impure metals requiring further processing. The approach could enable safer recycling practices while supporting India’s circular economy goals.“This green recovery process can significantly reduce pollution and environmental damage caused by e-waste while minimising demand for virgin metal mining. For society, the innovation promises safer recycling systems, cleaner ecosystems, and efficient use of natural resources, aligning with India’s sustainability and net-zero commitments,” said Prof Bauri.“Our research shows successful laboratory-scale results, validating its potential across multiple metals and real e-waste samples. The next phase will focus on scaling up the process for industrial applications, improving solvent recyclability, and testing cost-effective alternatives to enhance economic viability,” said Sinu Kurian.
