Dr Deblina Dutta, Assistant Professor, Department of Environmental Science and Engineering, and Ph.D. scholar Mr Lakshmi Kanth Moganti, have explored and discovered a cleaner and safer way to recover valuable metals from electronic waste, especially from the circuit boards inside electronic devices. In her recent paper titled “Deep eutectic solvents in E-waste recycling: preparation, properties, and hydrometallurgical metal recovery” published in the journal RSC Advances, Dr Dutta illustrates in her study that eco-friendly liquids called deep eutectic solvents can dissolve metals efficiently under mild conditions, meaning lower temperatures, less energy, and fewer harmful fumes.

Overall, the research shows that electronic waste can be treated as a useful resource rather than garbage. By using environmentally friendly solvents, valuable metals can be recovered safely, helping reduce pollution, conserve natural resources, and support sustainable recycling for the future.

Abstract

Deep eutectic solvents (DESs) are promising green solvents for hydrometallurgical metal recovery, formed by heating and mixing hydrogen bond donors and acceptors in specific molar ratios, where hydrogen-bond network formation rather than chemical reactions depresses the melting point and yields a stable, tuneable liquid phase. Owing to their low volatility, high polarity, low toxicity, and ability to complex metal ions, DESs provide an attractive alternative to conventional mineral acids for leaching metals from printed circuit boards (PCBs). This review critically examines preparation routes, key physicochemical properties relevant to metal dissolution, and their mechanistic role in enhancing leaching efficiency of DESs. A structured literature-selection approach was adopted by screening publications between 2003–2024 using keywords related to preparation of DES, metal recovery, and PCBs, focusing on studies reporting extraction efficiencies (85 to 100%), leaching mechanisms, recyclability, and solvent degradation. Across the surveyed literature, DESs such as choline chloride: ethylene glycol, choline chloride: urea, and choline chloride: oxalic acid consistently exhibits high efficiencies for copper (100%), nickel (100%), gold (≥95%), and silver (100%) recovery under mild operating conditions (40-100 ⁰C). Emerging trends include oxidation-assisted DES leaching and integration with electrochemical recovery. However, challenges such as high viscosity, mass transfer limitations, incomplete recyclability, and potential long-term degradation remain under-reported. Overall, this review signifies the current advancements, limitations, and knowledge gaps in DES-based hydrometallurgy and highlights future directions required for scalable, circular-economy-aligned recovery of valuable metals from E-waste.

Practical Implementation/ Social Implications of the Research

This research can be applied directly to recycling electronic waste, such as discarded computers, mobile phones, and batteries. The method studied uses environmentally friendly liquids to extract valuable metals instead of harmful acids or toxic chemicals. Because these liquids work at lower temperatures and are safer to handle, they can be used in small- to medium-scale recycling plants, especially in developing countries.

In practical terms, this means electronic waste recycling can become cheaper, safer, and less polluting. Recycling facilities would produce fewer toxic fumes and less hazardous wastewater, reducing risks to workers and nearby communities. The recovered metals like copper, gold, and nickel can be reused in manufacturing new electronic devices, reducing the need for mining fresh ores.

From a social perspective, this research supports environmental protection and public health by minimizing soil, water, and air pollution caused by conventional recycling methods. It also promotes resource conservation, as valuable metals are recovered from waste instead of being lost in landfills. Additionally, cleaner recycling technologies can help create green jobs and support a circular economy, where waste materials are reused rather than discarded.

Overall, this research contributes to a more sustainable society by turning electronic waste into a valuable resource while protecting people and the environment

Future research plans

Sustainable metal recovery from E-waste using green solvents like DES and using the recovered metals as a secondary resource which implements circular economy and SDGs.