Synthesis of metallic nanoparticles from Beta vulgaris using a single-pot green chemistry approach and their environmental engineering application

Abstract

In this study, a method for the green synthesis of nanoparticles using Beta vulgaris (B. vulgaris) extracts was developed. B. vulgaris was solely used in a synthetic, chemical-free, redox reaction, as a source of the precursor metal, reducing and capping agent. Metals accumulated in B. vulgaris were reduced to nanosize by betanin, an anthocyanin present in the B. vulgaris which has reducing and stabilising capabilities. Nanoparticles were synthesised in a solution containing 1% (v/v) B. vulgaris juice extract, at 80 °C and a pH of 8. The nanoparticles were characterised using TEM, SEM–EDS, UV–Vis, FTIR, and PXRD. It was determined that a hydroxyl group from the betanin releases an active H+ proton, which subsequently reduces metal ions. Results showed that spherical-shaped Ca-based crystal nanoparticles of approximately 5 nm were successfully synthesised using the developed method. Supplementing the Ca-based nanoparticles in biosurfactant producing cultures of Bacillus licheniformis STK 01 improved the emulsification index of kerosene from 20 to 50%—signifying the usability of the nanoparticles in environmental engineering applications in which hydrophobic compounds are targeted for bioremediation.