S. Sibmah Stalin; E.K. Kirupa Vasam Jino
Abstract
This present study involves the sonochemical and microwave synthesis of an efficient light harvesting nanocomposite photocatalyst, ZnO/GO embedded with copper nanoparticles. The synthesised nanocomposite was characterised by various spectroscopic methods like XRD, SEM, EDX, FT-IR, UV-DRS and fluorescence ...
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This present study involves the sonochemical and microwave synthesis of an efficient light harvesting nanocomposite photocatalyst, ZnO/GO embedded with copper nanoparticles. The synthesised nanocomposite was characterised by various spectroscopic methods like XRD, SEM, EDX, FT-IR, UV-DRS and fluorescence analysis. The catalytic activity of the synthesised nanocomposite was tested using an organophosphorous pesticide, as the test solution and its percentage efficiency of degradation were studied. About 99 % of 40 ppm of Quinalphos pesticide could be degraded using ZnO/Cu/GO nanocomposite (3 mg/L) under visible light radiation within20 min at neutral pH. The presence of an intrinsic defects and the fluorescence property of the prepared nanocomposite were also detected. The degradation efficiency was estimated by COD and TOC measurements. The reaction rate followed pseudo - first order kinetics with a rate constant of 0.042 min-1. Furthermore, the composite has demonstrated a reusable feature and was utilised for eight cycles without any change in its activity. These findings has illustrated an ecofriendly, more stable and well organised photocatalytic nanocomposite, which could be preferred much for the treatment of industrial and agricultural waste water containing organic contaminants within a short span of time under irradiation using sunlight.
Armin Ehsani Amoli; Mojtaba Masoomi; Mazyar Sharifzadeh baei; Fatemeh Babei; Ghasem Firouzzade pasha
Abstract
In this work, hydrothermal technique and precursor materials obtained from the wastes of filtration unit of gas pressure reduction station were used to create ZnO-Fe2O3 nanocomposite. FT-IR, FE-SEM, XRD and TEM analyzes were used to investigate the properties of the produced nanocomposite. XRD analysis ...
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In this work, hydrothermal technique and precursor materials obtained from the wastes of filtration unit of gas pressure reduction station were used to create ZnO-Fe2O3 nanocomposite. FT-IR, FE-SEM, XRD and TEM analyzes were used to investigate the properties of the produced nanocomposite. XRD analysis showed the structure of ZnO and Fe2O3 without impurities. The crystal size of ZnO-Fe2O3 nanocomposite was determined to be about 53 nm. FE-SEM images showed a nanocomposite pattern with an approximate diameter of 50 nm. Finally, visual decomposition of anionic and cationic dyes under visible light was used to study the photocatalytic activity of ZnO-Fe2O3 nanocomposite. By exposing a metal halide lamp to light and darkness for 60 minutes and 150 minutes, respectively, it was possible to study the photocatalytic activity of the synthesized nanocomposite in removing anionic and cationic dyes from aqueous medium. In the photocatalytic degradation of anionic and cationic dyes, the following factors were considered as essential variables: pH, initial dye concentration, nanocomposite content and exposure time. In this study, the degradation percentage of anionic and cationic dyes of ZnO-Fe2O3 nanocomposite with a ratio of 0.75:1 was 99.89 and 99.9%, respectively. The amount of band gap was calculated by Tack plot method and electrical conductivity was calculated using electrochemical impedance spectroscopy, which reduced the band gap. And the resistance increases. Due to the acceleration of charge transfer at the heterogeneous junction surface and the suppression of electron/hole pairs from recombination, the ZnO-Fe2O3 nanocomposite significantly increased the visible light current response.
Buvaneswari K; Arunadevi R; Sashikala S; Kavipriya K
Abstract
Visible light active ZnWO4/ZrO2 nanocomposite was prepared via hydrothermal method. The nanocomposite was characterized by UV-visible diffuse reflectance spectroscopy (UV-vis-DRS), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning Electron microscopy (SEM), energy dispersive ...
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Visible light active ZnWO4/ZrO2 nanocomposite was prepared via hydrothermal method. The nanocomposite was characterized by UV-visible diffuse reflectance spectroscopy (UV-vis-DRS), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning Electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and transmission electron microscopy (TEM) techniques. The XRD results showed that average particle size of ZrO2, ZnWO4 and ZnWO4/ZrO2 were found to be 29.20 nm, 23.78 nm and 20.14 nm respectively and the phase structure for ZrO2 and ZnWO4 in the composite was Rhombohedral and Monoclinic respectively. The UV–vis absorption spectra of the ZnWO4/ZrO2 nanocomposite noticeably shifted to the visible light region compared to that of the ZrO2. The prepared photocatalyst were composed of plate and spongy sphere with little agglomeration was seen from SEM result. The photocatalytic activities of the prepared nanocomposite was evaluated for the degradation of methyl orange (MO) under visible light irradiations. The effect of operational parameters such as initial dye concentration, pH, catalyst concentration and irradiation time have been investigated in detail. The photocatalytic degradation efficiency of ZnWO4/ZrO2, ZnWO4 and ZrO2 for 95%, 72% and 60 % respevtively. The high photocatalytic activity can be attributed to stronger absorption in the visible light region, a greater specific surface area, smaller crystal sizes, more surface OH groups, and to the effect of ZnWO4 doping, which resulted in a lower band gap energy.
Saied Saeed Hosseiny Davarani; Hamid Reza Moazami; Taher Yousefi; Masoud Abrari
Abstract
A flexible route for the electrosynthesis of visible light active CdxZn1-xO nanostructures has been proposed. Various nanostructures were prepared by anodic dissolution in 0.1M Me4NCl by using an applied potential of 15V for 30min. The prepared nanostructures were characterized by diffuse reflectance ...
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A flexible route for the electrosynthesis of visible light active CdxZn1-xO nanostructures has been proposed. Various nanostructures were prepared by anodic dissolution in 0.1M Me4NCl by using an applied potential of 15V for 30min. The prepared nanostructures were characterized by diffuse reflectance UV-Vis spectroscopy (DRS), Fourier transforms infrared spectrometry (FT-IR), X-Ray diffraction (XRD) and scanning electron microscopy (SEM). The results showed that the crystalline structure, morphology, and energy band gap of the products can be finely adjusted only by varying the duty cycle of the anodeswitching. The visible light activity of the obtained nanostructures was investigated using methyl orange as a model organic pollutant. It was found that the proposed method can be used to obtain very effective CdxZn1-xO photocatalysts by fine tuning of the morphology and energy band gap. The prepared photocatalyst retained 80% of its original activity after 5 replicated uses.