Synthesis of ZnO nanoparticles and its characterization

Abstract

Nanomaterials (NMs) tailored via conventional physicochemical routes play havoc with the environment which has led to the evolution of competent green routes for the actualization of a circular economy on an industrial scale. Green route of synthesis of nanoparticles has emerged as a revolutionary approach. The current study aimed to exploit plant and algal-mediated synthesis of ZnO nanoparticles (ZnO NPs), optimize the process for gram scale synthesis and use the ZnO NPs for the photocatalytic degradation of textile dyes (brilliant green and indigo caramine) and organic pollutants (bisphenol-A). One-step biosynthesis of ZnO NPs from biomolecules in lemon grass extract was carried out. The main objective was to investigate the role of aqueous extract of lemon grass in the production of ZnO nanoparticles. Different molecules were present in the crude extract of Lemon grass were identified by GC-MS and NMR (13C and 1H NMR) spectroscopy and observed 23 bioactive compounds in the extract rich in various forms of terpenoids, monoterpenes, keto-enol compounds, fatty acids, palmitic acid, and phytol along with some other ancillary phytochemicals which could be potential candidates for capping agents. The abundant presence of citral and photocitral-B in lemon grass extract acted as a coating and provides stability to ZnO NPs. Eco-friendly lemon grass capped ZnO NPs were synthesized using lemon grass extract and confirmed using different characterization techniques like UV- Vis spectroscopy, XRD, SEM and HR-TEM analysis. We found the size of the lemon grass capped ZnO NPs as 43.58± 3.2 nm and the shape of the particles as hexagonal through the HR-TEM analysis Phycosynthesis of ZnO NPs using a single-step process, from biomolecules present in the cyanobacterial extracts of Anabaena variabilis ARM 441 was carried out and analyzed for photocatalytic degradation of textile dyes. The primary focus was to explore the role of aqueous cellular extract of diazotrophic cyanobacterium A. variabilis ARM 441 in the fabrication