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Green-fabricated silver nanoparticles (AgNPs) are widely used in applications spanning from healthcare to industries due to their unique physicochemical, optical and catalytic properties. With that being said, they have recently been gaining widespread attention from the scientific community for their role in environmental remediation (also known as nanoremediation). Green synthesized AgNPs have shown to be efficient catalysts in the degradation of organic pollutants with one such example being para nitrophenol (PNP). PNP is a toxic organic compound and contaminant released in industry wastewater streams into water bodies like rivers and oceans which may harm aquatic life and even humans. The present study aims to synthesize AgNPs from the leaves of five Sri Lankan varieties of Solanum lycopersicum L. (tomato) and assess their ability to catalyze the degradation of PNP while also investigating if they pose cytotoxicity towards aquatic organisms. Four out of five varieties formed AgNPs under the optimum heating condition 90°C 60min as characterized by UV-Vis spectrophotometry. When subjected to scanning electron microscopy (SEM) analysis, AgNPs appeared spherical with an average diameter of approximately 40nm. Their bandgap energy was 2.70eV, classing them as semiconductors. Phytochemical analysis on leaf extracts revealed the presence of several phytoconstituents such as flavonoids, phenols, tannins and alkaloids required for the formation of AgNPs via bio-reduction. Catalytic activity was tested by the ability of AgNPs to degrade para nitrophenol (PNP) in the presence of NaBH4 and findings demonstrate that AgNPs catalyzed the degradation of PNP in under 75mins along with the formation of para aminophenol (PAP). Cytotoxicity of 4mg/mL and 1mg/mL AgNPs was studied in Artemia salina and results revealed 0% mortality of A. salina following 24h of exposure to AgNPs. Solanum lycopersicum L. is hence considered a good source of eco-friendly, non-toxic and biocompatible AgNPs that can efficiently degrade para nitrophenol. Synthesizing these AgNPs in large commercial quantities can help enhance environmental remediation efforts and effective wastewater management.
Hamza et al. (Sat,) studied this question.