An eco-friendly synthesis of ZnO nanoparticles with jamun seed extract and their multi-applications

Zinc oxide (ZnO) nanoparticles were synthesized via an ecofriendly route using Indian Jamun seed aqueous extract. The synthesized ZnO nanoparticles were characterized for their surface properties using characterization techniques such as UV-Visible, FTIR, XRD, SEM, EDX, and TEM. The synthesized ZnO nanoparticles were found to be spherical with a size ≤1 nm, as evidenced from SEM and TEM investigations. The XRD patterns confirm the formation of the wurtzite phase of ZnO nanoparticles. The ZnO nanoparticles were later investigated for their ability to remediate Hg2+ ions from aqueous solutions. Response surface methodology was employed to optimize the independent variables, and optimal results were achieved at pH 6, 45 min of contact time, and an initial concentration of 100 mg·L−1 Hg2+ ions. The applicability of the developed model was supported by a p-value of <0.0001 being significant, and 11 out of 20 runs resulted in above 75% of removal efficiency. The loading capacity of the ZnO nanoparticles was calculated to be 122.7 mg·g−1. The decolourization of methylene blue was achieved successfully with ZnO nanoparticles within 150 min. A moderate antimicrobial activity was exhibited by the ZnO nanoparticles synthesized in this study, with zones of inhibition of 15 and 14 mm for Escherichia coli and Staphylococcus aureus, respectively. The results conclude that the Indian jamun seed extract-mediated ZnO nanoparticles are excellent candidates for the remediation of Hg2+ ion-contaminated water streams.