Sustainable synthesis of silica nanoparticles (SNPs) from agricultural residues: A review on plant stress mitigation and the sustainability triangle

Silica nanoparticles (SNPs) have shown potential in a variety of applications across industries, including agriculture. Amid growing concerns about sustainable agricultural intensification and the environmental burden of synthetic agrochemicals, there is a pressing need for eco-friendly alternatives to support crop resilience. These nanoparticles can be sustainably extracted from agricultural residues such as rice hulls/husks, sugarcane bagasse, and corn cobs. These by-products are not only rich in silica but are also produced in large quantities annually, making them ideal candidates for SNPs production. This review discusses the synthesis methods of SNPs from agricultural residues and their potential to enhance crop productivity, particularly under abiotic stressors. The novelty of this work lies in its focus on the sustainability triangle – economic, environmental, and social sustainability – in the context of SNPs production from agricultural residues. Studies suggest that SNPs can mitigate the negative effects of various abiotic stresses, including salinity, drought, and heavy metal toxicity. However, despite their promising potential, the SNPs extraction process needs further optimization, considering the different isolation methods and process variables. To ensure scalable and responsible implementation, future research should also incorporate techno-economic analysis (TEA), life-cycle assessments (LCA), and relevant social sustainability factors.