Waste upcycling of Sapota peels as a green route for the synthesis of silver nanoparticles and their application as catalytic and colorimetric detection of Co and Hg.

Biochemical synthesis of nanoparticles (NPs) using plant part extracts as capping and reducing agents has drawn considerable attention in research with a growing focus on green chemistry. The present study utilized Sapota (Manilkara zapota L.) peel extract to synthesize silver nanoparticles (SP-AgNPs) using ultrasonic vibration. Different characterization techniques such as UV-vis spectroscopy, dynamic light scattering, Fourier Transform Infrared Spectroscopy, Field emission scanning electron microscope, High resolution transmission electron microscopy, and X-ray diffraction were employed to check the production of SP-AgNPs. The AgNPs were crystalline in nature and had an average particle size of 27.906 nm. The research primarily focused on two aspects: the catalytic activity of SP-AgNPs in degrading environmental pollutants and their ability to act as colorimetric sensors for toxic metal ions. SP-AgNPs exhibited significant catalytic activity in the decomposition of various pollutants such as Methyl Orange (0.035 ± 0.090 min, 92.89 ± 1.79%), Crystal Violet (0.1097 ± 0.1016 min, 85.56 ± 2.21%) and Cosmic Brilliant Blue G-250 (0.0697 ± 0.0275 min, 79.56 ± 1.80%). The high degradation percentages and reaction rate constants indicate the efficiency of SP-AgNPs in pollutant degradation. Additionally, the study demonstrated the effectiveness of SP-AgNPs as sensors for detecting toxic metal ions, particularly Co and Hg with limits of detection 54.40 ± 1.43 µM and 10.70 ± 0.16 µM. With impressive sensitivity and low detection limits, SP-AgNPs showed promise in detecting these ions, which are often found in environmental contaminants. Moreover, their plant-based synthesis, low toxicity, and cost-effectiveness make them attractive options for environmental remediation efforts.