The green synthesis of nanoparticles for antimicrobial, optical, and other electrical applications has attracted growing attention because it reduces chemical burden while maintaining higher efficacy. However, the environmental impacts associated with green NP synthesis have not been thoroughly studied and remain underexplored. Here, we present a comparative life cycle assessment (LCA) of AgZnO NPs synthesized via thermal/hot plate (HP) and ultrasonication-assisted (US) green methods. Using a gate-to-gate approach and the TRACI midpoint method in OpenLCA 2.0, we evaluated key environmental impact categories, including ecotoxicity, global warming, carcinogens, and fossil fuel depletion, for a functional unit of 1 kg of AgZnO NPs. Results indicate that the US method reduces carcinogens by 29%, ecotoxicity by 26%, global warming by 27%, and fossil fuel depletion by ∼20% compared to the HP method, primarily due to lower energy and solvent consumption. Sensitivity analysis revealed that ethanol, water, and energy inputs are the dominant contributors to the environmental burden, and optimizing these parameters can further decrease the impacts. Implementing 90% solvent recycling significantly enhances sustainability by reducing ecotoxicity by approximately 32–49%, fossil fuel depletion by 17–70%, and global warming potential up to 18–63% relative to the base case scenario. The result supports the idea that the US process, coupled with ethanol recovery, exhibits the lowest overall environmental impact. This study highlights the critical role of early process optimization and solvent recovery in green nanoparticle synthesis and provides a framework for developing resource-efficient, safer, and environmentally benign process pathways suitable for scale-up.
Noor et al. (Tue,) studied this question.