Photocatalytic degradation of acid violet dye by sunlight exposure using green synthesized magnesium oxide nanoparticles

Abstract

An aqueous extract of Phyllanthus Emblica fruit extract was used as a precursor in the effective synthesis of Magnesium Oxide Nanoparticles (MgONP) and the same was calcined at different temperatures. The thermal study demonstrated that MgO nanoparticles evolved from Mg(OH)2 by the identification of characteristic weight loss curves and endothermic peaks in TGA and DTA, respectively. UV-visible analysis showed that the peak shifts to a longer wavelength at 350 nm when the calcination temperature rises from 200 to 600°C, indicating a decrease in the size of MgONP particles. On the other hand, Tauc plot analysis showed that the band gaps between the precursor and calcined MgO samples varied from 5.84 to 3.70 eV. FTIR and XRD analysis confirmed the synthesis of MgONPs from Mg(OH)2 exhibiting spherical shapes of around 20nm in size. Twenty minutes of exposure to sunshine caused the dye's colour to entirely vanish, demonstrating the remarkable photocatalytic effectiveness of MgONP calcined at 600°C. The effective breakdown of Acid Violet was confirmed by the rate constant of the photocatalytic behaviour increasing proportionately with the catalyst dose. Furthermore, it was suggested by the Langmuir and Freundlich isotherm models that Acid Violet efficiently adheres to the photocatalyst surface when R2 values are nearer to 1. There are several potential applications for MgO nano adsorbents in dye removal processes, as evidenced by desorption studies that showed their reusability.