Sustainable synthesis of functional nanomaterials: renewable resources, energy-efficient methods, environmental impact and circular economy approaches

Conventional nanomaterials synthesis methods often depend on toxic reagents, energy-intensive processes, and produce considerable hazardous waste, causing serious risks to both environmental and human health. This review addresses these concerns by highlighting innovative and sustainable synthesis approaches that not only reduce ecological impact but also align with the circular economy principles and international sustainability frameworks. The authors critically discuss the use of renewable resources, such as plant extracts, agricultural residue, and algae as eco-friendly substitutes for traditional chemical starting materials. The environmental and technological benefits of low-energy methods, such as mechanochemical, microwave-assisted, and photochemical routes, are discussed in detail. Furthermore, the authors discuss the purpose of closed-loop systems, eco-friendly solvents including ionic liquids and deep eutectic solvents, and green catalysts that all contribute towards supplying lower environmental impacts. A comparative life cycle analysis is presented to assess the advantages and trade-offs of different synthesis routes. Finally, the authors proposed biomimetic approaches, synthetic biology, and hybrid systems as candidate paths for future development of sustainable nanotechnology through the utilization of AI. By presenting an integrated and interdiscipline examination of these issues, this review provides a comprehensive roadmap towards expanding green synthesis of nanomaterials and achieving planetary health.