Synthesis and Characterization of Stephania abyssinica leaf extract mediated (Mn, Ni) Co-doped ZnO nanoparticle for Degradation of Methylene Blue

Abstract

The dye from industrial processing makes the water to be contaminated which is toxic and hasbig problem on health. One of the most basic means of obtaining cleaned water is the removal of dye from wastewater. Employing semiconductors as a photo catalyst is an attractive method for the removal of organic dye pollutants in wastewater. In this study, The ratio of extracted leaf to zinc nitrate in the ratio of 1:2, 1:1, 2:1 v/v are done, and their names are assigned as L1:Z2, L1:Z1, and L2:Z1. ZnO doped with Mn and Ni as Zn0.98Mn0.02O and (Zn1-xNixO, x = 0.01, 0.03, 0.05, 0.07) is prepared using the Stephania abyssinica (S. abyssinica) leaf andassigned as 2MZO, 1NZO, 3NZO, 5NZO, and 7NZO respectively. Moreover, the (Mn, Ni) Co doped ZnO nanostructures using S. a byssinica leaf is synthesized by co-precipitation method as Zn0.98-xMn0.02NixO (x = 0.01, 0.03, 0.05, 0.07, 0.09) and assigned as 1NMZO, 3NMZO, 5NMZO, 7NMZO and 9NMZO respectively. Furthermore, the samples were characterized bydifferent technique. The X-ray powder diffraction (XRD) results confirmed that ZnO is crystalline 3D hexagonal structure with no other impurities peaks, and crystalline sizes varied from 36.17 to 17.32 nm due to leaf extract and the dopant concentration, and phase shift was occurred due to Ni/Mn dopant concentration. The presence of leaf extract increased the surface area from 14.53 (m2 g-1) to 28.256 (m2 g-1), prevented aggregation and controls particle size. Due to doping of Ni/Mn, the tuned band gap is tuned from 3.2 eV (Uv light) to 2.62 eV (visible light), PL intensity indicated the recombination rate decreased and charge transfer resistance is well decreased. The photo catalytic activities of pure-ZnO, L2:Z1, L1:Z2, L1:Z1, 2MZO, 1NZO, 3NZO, 5NZO, 7NZO, 1NMZO, 3NMZO, 7NMZO and 9NMZO catalysts were tested towards the degradation of Methylene Blue (MB), and 33.1 %, 69.7 %, 67.4 %, 72.5 %, 76 %, 72.8 %, 74.12%, 79.7%, 78 %, 84 %, 92 %, 97%, and 92% of MB dye was degraded, respectively. Among the catalysts, 5NMZO catalysts had the highest performance and 99.5 % MB dye was degraded within 80 min irradiation. The higher degradation efficiencies could be due to the low recombination, lower electron transfer resistance, high absorption of visible light, low agglomeration, and high surface area. Therefore, preparation of (Mn, Ni) Co-doped ZnO using Stephania abyssinica leaf extract is a good candidate for degradation of MB under visible light.