Sustainable use of mining and electronic waste for nanomaterial synthesis with technological applications: state of the art and future directions

In the last years, the study of metals recovery and nanoparticle transformation from industrial residues has gained attention because this theme contributed to improving the valorization of the so-called wasted, transforming the simple recycling strategies to more complex and highly technological new approach methodologies, delivering added value to raw materials and allowing the development of new advanced materials with unique physicochemical characteristics for multiple functionalities according to the new growing demands. The present work reviews the available literature about using mining and electronic waste (e-waste) for recycling-extracting metallic products and their transformation into nanomaterials (NMs). The applications and challenges of these NMs were also analyzed and discussed. Acid and alkaline treatments were the main recovery methods, while the synthesis by chemical reduction was the most used for the fabrication of NPs. Nano-alloy, Cu, Fe, and Au NPs were the main products obtained from PCBs and tailing waste. In addition, catalysis, sensors, and antimicrobial activity were the primary applications described. Due to the reutilization of metallic raw, direct transformation, low-cost, and eco-friendly synthesis processes could be an attractive alternative to the production of NPs on large scales.