Photocatalytic Degradation of Methylene Blue Dye from Wastewater by Using Doped Zinc Oxide Nanoparticles

• Published in: Water (Basel) Vol. 15; no. 12; p. 2275
• Main Authors: Modi, Shreya, Yadav, Virendra Kumar, Amari, Abdelfattah, Alyami, Abeer Yousef, Gacem, Amel, Harharah, Hamed N, Fulekar, Madhusudan Hiraman
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 01-06-2023
• Subjects: Adsorption; Annealing; Antimony; Aqueous solutions; band-gap; Catalysts; Caustic soda; Chemical properties; Color removal; Degradation; Diffraction; doped ZnO; Doping; Dyes; Efficiency; Emission analysis; Field emission microscopy; Field emission spectroscopy; Fourier transforms; Functional groups; Hazardous wastes; Impurities; Infrared spectroscopy; Irradiation; Light; Methylene blue; Nanomaterials; Nanoparticles; Nitrates; Photocatalysis; photocatalyst; Photocatalysts; Photodegradation; Photovoltaic cells; Radiation; Scanning electron microscopy; Semiconductor materials; Semiconductors; Solar radiation; Spectrum analysis; Structural analysis; Structure-function relationships; Thin films; Transmission electron microscopes; Tungsten; Ultraviolet reflection; Ultraviolet spectroscopy; Wastewater; Wastewater discharges; Wurtzite; X-ray diffraction; X-rays; Zinc oxide; Zinc oxides; India
• ISSN: 2073-4441; 2073-4441
• DOI: 10.3390/w15122275

ZnO is a semiconductor material that has important physical and chemical properties, which are frequently and significantly enhanced by the addition of impurities, such as doping. A study of the structural properties of pristine and functionalized (i.e., doped with Antimony and Tungsten) ZnO nanoparticles has been conducted for the photocatalyst-based degradation of methylene blue (MB) dye under both Ultraviolet (UV) and solar light. Authors have used a 1% concentration of dopant for doping purposes. The synthesized materials were characterized for structural analysis, functional group identification, spectroscopic measurements, and morphological examination using X-ray diffraction (XRD), Fourier transform-infrared (FTIR), UV-Vis spectroscopy (UV-Vis), and Field emission scanning electron microscope (FESEM) techniques. XRD analysis confirmed that the synthesized-doped materials retained the wurtzite hexagonal structure with a purity of 99%. Transmission electron microscope (TEM) analysis data reveals the average size of pure ZnO-NPs was found to be 7 nm; after doping the size was found to be increased to 18 nm and 9.55 nm, respectively, for ZnO-W and ZnO-Sb. As per FESEM analysis results, minor morphological changes were observed after doping. The Ultraviolet Differential reflectance spectroscopy UV-DRS study revealed the confirmation of ZnO doping with antimony and tungsten, which exhibited a blue shift. The decrease in the band-gap on doping makes the ZnO-NPs more efficient for photocatalytic applications. The photocatalytic efficiency of pristine and doped ZnO-NPs catalysts for methylene blue photocatalytic degradation (PCD) was analyzed under both UV and solar irradiation. This study analyzed the effect of pH, nano-photocatalyst dose, and initial dye concentration (ICD) on the PCD of MB. The obtained analytical results showed that the ideal conditions for the PCD of MB dye are as follows: pH = 9, the quantity of the nano-photocatalyst used was 300 mg/L, and an initial MB dye dose of 10 ppm. These conditions lead to a PCD of about 91% of the MB dye by using ZnO-Sb nano-photocatalyst on exposure to solar radiation. The reusability study also revealed the stability of nano-photocatalysts. The current research may pave the way for the removal of hazardous dyes from wastewater discharged by many industries.