Degradation of toxic methylene blue dye with Zinc oxide (ZnO) nanoparticles synthesized by leaf extract of Madagascar periwinkle plant

In this paper, we have synthesized ZnO nanoparticles namely ZnO (L5) and ZnO (L10) nanoparticles. Both ZnO (L5) and ZnO (L10) nanoparticles have been synthesized by biosynthesis methods using Madagascar periwinkle leaf extract. The biosynthesis method is simple, eco-friendly, and cheap. ZnO (L5) and ZnO (10) nanoparticles have been characterized by using X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive Spectroscopy (EDS), UV- Visible Spectroscopy, Fourier Transform Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscopy (FESEM), Brunauer–Emmett–Teller (BET), and Transmission Electron Microscopy (TEM). The Powder X-ray diffraction (PXRD) revealed that synthesized ZnO (L5) and ZnO (L10) consist of a typical hexagonal wurtzite phase. The size and morphology of synthesized ZnO (L5) and ZnO (L10) nanoparticles were determined using Scanning Electron Microscopy (SEM), Field Emission Scanning Electron Microscopy (FESEM), and Transmission Electron Microscopy (TEM). The FTIR study reveals that phytochemicals from the leaf of the Madagascar periwinkle leaf extract are present on the surface of synthesized ZnO (L5) and ZnO (L10) nanoparticles. The BET analysis shows that the measured surface areas of ZnO (L5) and ZnO (L10) nanoparticles are 10.202 m²/g and 38.762 m²/g respectively. The photocatalytic activity of both the synthesized nanoparticles was determined against methylene blue (MB) organic dye. It was evident from the results that ZnO (L10) is a better catalyst than ZnO (L5). Herein, MB dye was degraded (94.09%) in 600 min by ZnO (L5) photocatalyst and (97.92%) in 360 min by ZnO (L10) photocatalyst. Therefore synthesized ZnO (L5) and ZnO (L10) nanoparticles could be employed as an efficient photocatalyst for the degradation of toxic organic dyes.