Decolorization of Toxic Dyes using Biosynthesized Manganese Oxide Nanoparticles under Sun Light

Abstract

Manganese oxide nanoparticles (MnO2-NPs) have been biosynthesized using the aqueous extract of the plant powder of Lagerstroemia speciosa. This plant contains steroids, terpenoids, glycosides, phenolic compounds, α-amino acids, saponins, starch, alkaloids, carbohydrates, organic acids, flavonoids, reducing sugars, and tannins. The phenolic compounds in the extract are exploited as reducing and capping agents. Biosynthesized particles have been characterized using UV-VIS-IR, XRD, FESEM, TGA, DSC, and FTIR analysis. The UV-Vis-IR spectrum clearly showed an absorption peak at 365 nm, which indicated the formation of MnO2-NPs. It is evident in the FESEM images that the biosynthesized particles are rough, spherical, and arbitrarily oriented with a size of about 83–400 nm. The XRD analysis revealed a pure tetragonal structure for MnO2-NPs with preferential orientation at (110) planes of reflection. Furthermore, the photocatalytic activity of MnO2-NPs has been investigated by decolorizing methyl orange (MO) and bromocresol green (BCG) dyes under sunlight.