Effect of pH Value on the Bandgap Energy and Particles Size for Biosynthesis of ZnO Nanoparticles: Efficiency for Photocatalytic Adsorption of Methyl Orange

Abstract

In this paper, ZnO nanoparticles (NPs) were greenly synthesized at different pH values of 4, 6, 9.5, and 11 via Portulaca oleracea leaf extract, and the effect of pH on the optical and structural properties was studied. UV-Vis spectrophotometers and FTIR spectroscopy characterized the optical properties. Meanwhile, the structural properties were characterized via Scanning Electron Microscopy (SEM) and X-Ray Diffraction (XRD). Furthermore, their photocatalytic dye degradation was examined against methyl orange dye. The characterization results have confirmed the successful biosynthesis of ZnO nanoparticles with a size ranging between 22.17 to 27.38 nm. The synthesis pH value significantly influenced ZnO NPs' optical and morphological properties. The results have also indicated the high performance of the greenly synthesized ZnO NPs for dye degradation.

Green Synthesis of NiO-SnO2 Nanocomposite and Effect of Calcination Temperature on Its Physicochemical Properties: Impact on the Photocatalytic Degradation of Methyl Orange

“…SnO 2 NPs have been fabricated using physical and chemical methods such as laser ablation, the sol–gel method, spray pyrolysis, microemulsion, microwaves, electrochemical deposition, co-precipitation, and hydrothermal, sonochemical, solvothermal, and non-aqueous routes [ 20 , 30 , 31 ]. Importantly, the paucity of reports on the photodegradation of dyes with NiO NPs and SnO 2 NPs compared to TiO 2 NPs and ZnO NPs [ 7 , 13 , 14 , 18 , 21 , 22 , 32 ] justifies the present study.…”

“…Methyl orange (MO) is an anionic azo dye that is used in the paper, pharmaceuticals, food, cosmetics, and textile industries [ 7 , 8 , 9 ]. Owing to its slow biodegradability, MO remains in the environment for a long period and represents an organic pollutant [ 7 , 8 , 9 ].…”

“…Methyl orange (MO) is an anionic azo dye that is used in the paper, pharmaceuticals, food, cosmetics, and textile industries [ 7 , 8 , 9 ]. Owing to its slow biodegradability, MO remains in the environment for a long period and represents an organic pollutant [ 7 , 8 , 9 ]. Several methods such as adsorption, incineration, membrane filtration, coagulation, and absorption have been used for dye removal [ 9 ], but they did not prove efficient as they generated disposal problems, came at a high cost, and were time-consuming.…”

“…Compared to the other alternatives, semiconductor-based photocatalytic degradation has been proven to be an efficient, rapid, economical, and environmentally friendly process [ 10 , 11 , 12 ]. The photocatalysis process obeys the basic principle of the advanced oxidation process (AOP) to generate reactive radical species with UV radiation to catalyze organic pollutant degradation [ 7 , 13 , 14 ].…”

“…Different types of metal and metal oxide nanoparticles have been synthesized for various applications, such as catalysis, energy storage devices, dye-based solar cells, and biomedicines [ 2 , 7 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 ].…”