GREEN HYDROTHERMAL SYNTHESIS OF Ag@Guajavapsidium LEAF BIOCHAR NANOCOMPOSITE AND THE EVALUATION OF THE PHOTOCATALYTIC AND ANTIMICROBIAL ACTIVITIES

Abstract

An Environmental and health concern requires an alternative fabrication route for nanomaterials because of the high toxicity and cost of reagents. In this study, the phyto-fabrication of silver grafted guava leaf extract and biomass biochar nanocomposite was executed using a novel, facile, low cost, sustainable and eco-friendly route. The formation of the nanocomposite was evidenced through UV spectroscopic analysis with surface plasmon resonance peak at 349 nm. The Fourier transform infrared spectroscopy (FTIR) and energy dispersive spectroscopy (EDX) also confirmed the formation of the nanocomposite as illustrated by the spectra change and presence of Ag+ ions on the surface of the nanocomposite respectively. The x-ray diffraction (XRD) and scanning electron microscopy (SEM) confirmed the crystal structure and spherical, porous nature with a size range of 25 to 40 nm of the nanocomposite respectively. The potential of nanocomposite in the removal of MBwas evident under different conditions as it reached nearly 100% under the optimum reaction conditions (methylene blue (MB) concentration; 10 ppm, a dose of Ag/extract /biochar; 0.01 g, temperature; 25 °C). The novel nanocomposite regeneration and reusability was promising, as the removal efficiency of MB from solution after five cycle reuse was above 80 %. Antimicrobial evaluation of the nanocomposite using Escherichia coli Klebsiella pneumonia, staphylococcus aureus and salmonella specie revealed that it is an excellent antimicrobial agent with 9, 8, 15 and 5 mm zones of inhibition respectively.