Enhancing the Photocatalytic Properties of ZrO2/ZnO Nanocomposite Supported on Montmorillonite Clay for Photodegradation of Congo Red (original) (raw)
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Photocatalytic degradation of Congo red by ZnO nanoparticles with different morphology
Journal of Interfaces, Thin Films, and Low dimensional systems, 2019
In this study, ZnO nanoparticles in three shapes, spherical, rod, and sheet are synthesized by a hydrothermal method using three different surfactants, namely three ethanol amine, cetyl three methyl ammonium bromide, and sodium dodecyl sulfate. In all cases, the chemical composition, powder identification, morphology. and particle size of the final product are characterized by Fourier transform infrared (FTIR), X-ray diffraction (XRD), field emission scanning electronic microscopy (FESEM), EDX elemental analysis, and UV-Vis spectroscopy. The photocatalytic activity of the nanoparticles are investigated for degradation of organic pollutants (Congo red dye). The removal tests of Congo red as a water organic pollutant indicates photocatalytic activity and absorption ability of synthesized zinc oxides. Finally, the comparison of the dye removal results show that the rod nanoparticle has more efficiency in the degradation of Congo red with 97% yield over 2 hours at pH=8.
Photocatalytic degradation of Congo red using zinc sulphate as a catalyst
The present study involves the photocatalytic decolorization of Congo Red (CR) by employing heterogeneous photocatalytic semiconductor. An attempt has been made to study the effect of process parameters viz., amount of catalyst, concentration of dye, pH, and irradiation time on photocatalytic degradation of Congo Red. The experiment was carried out by irradiating the aqueous solutions of CR containing photocatalysts inside the batch reactor having UV light. The rate of decolorization was estimated from residual concentration by spectrophotometrically. Similar experiments were carried out by varying pH (2–14), amount of catalyst (0.05–0.2 g/l) time variation (2-30) minutes and initial concentration of dye (2-100 mg/l). The experimental results indicated that the maximum decolorization of CR (more than 90%) occurred at pH 7 using ZnSO 4. The performance of ZnSO 4 /UV was excellent throughout the experiment.
Photocatalytic degradation of Congo Red dye by using nano ZnO and Ni-Co-ZnO nanocomposites
2018
Photocatalysis has attracted significant attention as a potential issue for the degradation of toxic organic pollutants such as Congo Red. In this research spherical Pure ZnO nano particles and Ni-Co-ZnO nano composites (Zn0.95Ni0.04Co0.01O, Zn0.95Ni0.025Co0.025O and Zn0.95Ni0.01Co0.04O) have been synthesized by precipitation method. X- ray diffraction, Fourier transform Infra Red ,field emission scanning electron microscopy, EDX and ICP analysis confirmed the structure and composition of the samples. The x-ray diffraction analysis (XRD) showed that all samples prepared were about Wurtzite structure and average crystal size of 17nm. Field emission scanning electron microscopy (FESEM) analysis revealed the spherical shape of all samples. The Fourier transform infrared spectroscopy (FT-IR) revealed bands at 435 cm-1, 480 cm-1 and 525 cm-1 are related to Zn-O bonds, related to the stretching vibrating bonds of ZnO. The results illustrated the Ni and Co ions substituted the Zn ions ...
Journal of Chemical Engineering & Process Technology, 2011
The photocatalytic degradation of Congo red in aqueous solution was investigated under UVA light at different operating conditions, including irradiation time, pH solution and band gap of MO 2 (M=Ti +4 and Ce +4) and M' 2 O 3 (M'=Al +3 and Fe +3) semiconductor groups by UV-spectrophotometric monitoring. The results showed slight stability of 597nmband of CR over the pH range of 6-7, while, it almost completely disappeared at pH higher than 7. Maximum photo degradation was obtained at pH 8 as a result of 95.02% degradation efficiency of CR for 60 min of irradiation time. The photo decomposition efficiency of MO 2 (M=Ti +4 and Ce +4) semiconductor group was higher, compared to that of M' 2 O 3 (M'=Al +3 and Fe +3). Photodecomposition reactions correlated with pseudo-first-order kinetic model. These findings can support the design of remediation processes and also assist in predict their fate in the environment.
Separation and Purification Technology, 2014
The utilisation of titanium dioxide (TiO 2) in a coupling system membrane photocatalytic reactor (MPR) has been widely investigated. However, there have been very few studies regarding the zinc oxide (ZnO) photocatalyst in MPR, although it has been shown to provide better efficiency than TiO 2 in certain cases, mainly for dye photodegradation. In this study, the influence of ZnO nanoparticles in MPR has been investigated for Congo red (CR) dye treatment. Four types of ZnO were synthesised via the precipitation of oxalic acid and zinc acetate solutions. The X-ray diffractometry (XRD) and transmission electron microscopy (TEM) results showed that precipitation is a valuable method for producing the smallest particle size (7-30 nm) of ZnO without any agglomerations, especially under stirring conditions in the presence of PVP (ZnO-PVP-St). As expected, the ZnO-PVP-St presented the great potential in MPR in terms of the highest photodegradation efficiency and lesser membrane flux decline, which was supported by the FESEM results. From the EDX analysis, it was confirmed that the small amount of ZnO-PVP-St did not pass through the membrane pores to the final stream. It was believed that the other remaining ZnO was reused in the photocatalytic reactor, for the continuous process of MPR. Due to the effective surface area of ZnO-PVP-St and adsorption of UV light, the optimum photocatalyst loading for the system was 0.3 g L À1 under 20 mg L À1 dye concentration and pH 7 of the initial CR dye solution.
Catalysts, 2021
Degradation of organic dyes and their byproducts by heterogeneous photocatalysts is an essential process, as these dyes can be potentially discharged in wastewater and threaten aquatic and xerophyte life. Therefore, their complete mineralization into nontoxic components (water and salt) is necessary through the process of heterogeneous photocatalysis. In this study, Zr/CrO2 (Zirconium-doped chromium IV oxide) nanocomposite-based photocatalysts with different compositions (1, 3, 5, 7 & 9 wt.%) were prepared by an environmentally friendly, solid-state reaction at room temperature. The as-prepared samples were calcined under air at 450 °C in a furnace for a specific period of time. The synthesis of Zr/CrO2 photocatalysts was confirmed by various techniques, including XRD, SEM, EDX, FT-IR, UV-Vis, and BET. The photocatalytic properties of all samples were tested towards the degradation of methylene blue and methyl orange organic dyes under UV light. The results revealed a concentration-...
Nanosystems: Physics, Chemistry, Mathematics, 2016
Zinc oxide-palladium nanocomposite material (ZnO-Pd) N CM was prepared and then characterized by UV-Vis spectroscopy, photoluminescence spectroscopy, X-ray diffraction analysis, energy dispersive X-ray analysis and field emission-scanning electron microscopy. The photocatalytic performance of (ZnO-Pd) N CM was investigated by degradation of Congo red under solar light irradiation. Zinc oxide modified with palladium metal could greatly enhance its photocatalytic activity and effectively degraded by Congo red dye.
Catalysts
Zinc chromite (ZnCr 2 O 4) has been synthesized by the thermolysis of a new Zn(II)-Cr(III) oxalate coordination compound, namely [Cr 2 Zn(C 2 O 4) 4 (OH 2) 6 ]•4H 2 O. The coordination compound has been characterized by chemical analysis, infrared spectroscopy (IR), and thermal analysis. The zinc chromite obtained after a heating treatment of the coordination compound at 450 • C for 1 h has been investigated by XRD, FE-SEM, TEM/HR-TEM coupled with selected area electron diffraction (SAED) measurements. The photocatalytic performance of nanosized zinc chromite was assessed for the degradation and mineralization of humic acid (HA) from a drinking water source, envisaging the development of the advanced oxidation process for drinking water treatment technology. A mineralization efficiency of 60% was achieved after 180 min of 50 mg L −1 HA photocatalysis using zinc chromite under UV irradiation, in comparison with 7% efficiency reached by photolysis.
Journal of Water and Environmental Nanotechnology, 2021
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.
Journal of Molecular Catalysis A: Chemical, 2011
The sol-gel route has been applied to obtain ZnO-TiO 2 thin films. For comparison, pure TiO 2 and ZnO films are also prepared from the corresponding solutions. The films are deposited by a spin-coated method on silicon and glass substrates. Their structural and vibrational properties have been studied as a function of the annealing temperatures (400-750 °C). Pure ZnO films crystallize in a wurtzite modification at a relatively low temperature of 400 °C, whereas the mixed oxide films show predominantly amorphous structure at this temperature. XRD analysis shows that by increasing the annealing temperatures, the sol-gel Zn/Ti oxide films reveal a certain degree of crystallization and their structures are found to be mixtures of wurtzite ZnO, Zn 2 TiO 4 , anatase TiO 2 and amorphous fraction. The XRD analysis presumes that Zn 2 TiO 4 becomes a favored phase at the highest annealing temperature of 750 °C. The obtained thin films are uniform with no visual defects. The optical properties of ZnO-TiO 2 films have been compared with those of single component films (ZnO and TiO 2). The mixed oxide films present a high transparency with a slight decrease by increasing the annealing temperature.