Photocatalytic degradation of methylene blue using ZnO and 2%Fe–ZnO semiconductor nanomaterials synthesized by sol–gel method: a comparative study

Abstract

ZnO and 2%Fe-ZnO nanomaterials were prepared by using a low-cost sol-gel method. The synthesized nanomaterials were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDX). The XRD and SEM studies reveal that the synthesized nanomaterials have a hexagonal wurtzite structure with average crystalline size ~ 22 to 23 nm. EDX analysis confirmed the composition and purity of synthesized nanomaterial. The photocatalytic activity of synthesized nanomaterials was monitored using the spectrophotometric method. Also, the photocatalytic removal of methylene blue (MB) dye from its aqueous solution by using ZnO and 2%Fe-ZnO nanopowder under UV light irradiation was studied. The effect of various parameters such as pH of dye solution, dye concentration, contact time and catalyst dose were investigated. Results of the current study demonstrated that, the maximum degradation using ZnO was 86% and that for 2%Fe-ZnO was 92% (under the optimum condition initial dye concentration = 10 mg/L and pH = 2). This study showed that 2%Fe-ZnO is a promising and better photocatalysts than ZnO.

Microwave assisted synthesis of zinc oxide (ZnO) nanoparticles in a noble approach: utilization for antibacterial and photocatalytic activity

“…, (112), (201) planes were for the synthesized ZnO nanoparticles which is similar to other finding [39].…”

“…9) [53]. The radicals originate from the oxidation of absorbed water or absorbed OH − and the presence of oxygen prevents the re-combination of electron-hole pairs which are generated by light of suitable energy absorbed by the ZnO nanoaparticles [39].The plenty of radicals produced by the absorbing more electron by surface oxygen enhances the discoloration and degradation of methylene blue by mineralization of the various intermediates…”

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“…Generally, the degradation of MB solution by ZnO particles could be explained by the mechanism below [16,17,26]. When ZnO photocatalyst is irradiated by light with an energy higher or equal to the bandgap, an electron in the valence band (ecb -) will be excited to the conduction band and leaving a generation of a hole in the valence band (hvb + ) on the surface of ZnO particles as shown in (Eq.…”

Microwave-assisted biosynthesis and characterization of ZnO film for photocatalytic application in methylene blue degradation

“…Synthetic dyes containing organic compounds have been frequently used in the textiles, paper, printing, food, and cosmetics industries to make their products. They are difficult to decompose and may cause environmental problems [1]. Methylene blue (MB) dye is one of the liquid wastes that are most commonly found.…”