Photocatalytic Decomposition of Methylene Blue over Nanosized Ca2+ Doped LaMnO3 under Visible Light Irradiation (original) (raw)
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Journal of Saudi Chemical Society, 2015
Visible light induced semiconductor photocatalysis has received a great attention in recent years due to the contamination of water bodies. In the present study, we have reported the photo catalytic degradation of a toxic organic dye, malachite green using a ZnO doped Dy 2 O 3 photo catalyst under visible light irradiation. The nanocrystalline photocatalyst was prepared by a precipitation method employing the respective nitrates and sodium carbonate as precursors and were characterized by FT-IR, XRD, UV-Vis DRS, FE-SEM and AFM analysis. The experimental results proved that the prepared photo catalysts were crystalline, nanosized and highly active in the visible region. UV-Vis DRS results suggested that the band gap was 3.1 eV for the prepared photo catalyst. The photodegradation efficiency of malachite green was analysed by various experimental parameters namely pH, catalyst dosage, variation of substrate concentration and effect of electrolyte addition. The photo degradation process followed a pseudo first order kinetics and was continuously monitored by UV-Visible spectrophotometer. The degradation of malachite green was above 99% within 1 h of visible light irradiation employing the doped photocatalyst, whereas pristine metal oxide possessed only 67% and pristine lanthanide oxide possessed activity which was only due to photolysis. A plausible mechanism for the generation of OH radicals and the pathway for MG dye degradation has been proposed in this study. The experimental results clearly show that nanocrystalline semiconductor doped lanthanide oxides are highly active under visible light irradiations and may find wider applications in environmental remediation technologies.
Methyl orange degradation over nano-LaMnO3 as a green catalyst under the mild conditions
Nanochemistry Research, 2019
This study was conducted to investigate the use of cubic LaMnO3 nano-perovskite as a green catalyst for the degradation of an aqueous solution of methyl orange under different conditions. Nanoscale cubic lanthanum manganite with the particle size of ~20 nm was successfully synthesized via citrate sol-gel method. The sample was characterized using the FT-IR and UV-Vis spectroscopy, XRD, SEM, and TEM analysis. The particle size of catalyst was calculated by Scherer equation using data of XRD analysis. The calculations along with an analysis of SEM and TEM confirm the formation of nanosized perovskite phase. The behavior of this nanocatalyst for degradation of an aqueous solution of methyl orange was investigated at wavelengths of 300-700 nm. The effects of the type and different amounts of acid, the absorbent content, pH, and temperature were studied for obtaining the optimal conditions of degradation. The prepared sample shows a suitable activity for the methyl orange degradation under dark (~90%) condition. The solar catalytic degradation is faster and goes up to about 100% after 60 min, indicating a different reaction pathway with less activation energy. Pre-visible-light degradation is the basis of catalytic activity of lanthanum manganite. A parallel photocatalytic reaction, however, is an almost simpler way to destroy the azo dyes over LaMnO3 nanoperovskite, which makes the LaMnO3 as a proper photocatalyst for degradation.
This study was conducted to investigate the use of cubic LaMnO 3 nanoperovskite as a green catalyst for the degradation of an aqueous solution of methyl orange under different conditions. Nanoscale cubic lanthanum manganite with the particle size of ~20 nm was successfully synthesized via citrate sol-gel method. The sample was characterized using the FT-IR and UV-Vis spectroscopy, XRD, SEM, and TEM analyses. The particle size of catalyst was calculated by Scherer equation using data of XRD analysis. The calculations along with an analysis of SEM and TEM confirm the formation of nanosized perovskite phase. The behavior of this nanocatalyst for degradation of an aqueous solution of methyl orange was investigated at wavelengths of 300-700 nm. The effects of the type and different amounts of acid, the absorbent content, pH, and temperature were studied to obtain the optimal conditions of degradation. The prepared sample shows a suitable activity for the methyl orange degradation under dark (~90%) condition. The solar catalytic degradation is faster and goes up to about 100% after 60 min, indicating a different reaction pathway with less activation energy. Pre-visible-light degradation is the basis of catalytic activity of lanthanum manganite. A parallel photocatalytic reaction, however, is an almost simpler way to destroy the azo dyes over LaMnO 3 nanoperovskite, which makes the LaMnO 3 as a proper photocatalyst for degradation.
Solar photodegradation of methylene blue by LaMnO3 nanorods as a heterogeneous catalyst
2011
Semiconductor photocatalysis has proved to be an efficient method for decolorization and degradation of pollutants. The potential of the prepared photocatalyst in degradation of methylene blue (MB) dye under sunlight irradiation was studied. Characterization of LaMnO 3 nanorods of prepared sample was studied using X-ray powder diffraction (XRD), TG/DTA, SEM, TEM and BET methods. The influence of experimental parameters on the dye photodegradation process was studied and it was observed that photo reactivity of photocatalyst (LaMnO 3) varied with the amount of catalyst, initial dye concentration, pH of the dye solution, H 2 O 2 oxidant. The optimal experimental conditions were determined as follow: catalyst amount; 0.16gm/L, concentration of the dye solution; 10 ppm, pH of solution; 9.3 and 6% H 2 O 2 solution under these optimum conditions, the obtained degradation efficiency for MB dye was 100 %. The reusability of the intended catalyst was also investigated.
Journal of Inorganic and Organometallic Polymers and Materials
This study successfully synthesized Li2MnSiO4/Mn3O4 (LMS/M3) and Li2Mn0.8Ni0.2SiO4/Mn3O4 (LMNS/M3) nanocomposites in a two-step method first, by preparing Mn3O4 (M3) nanoparticles through a hydrothermal method and second, by synthesizing Li2MnSiO4 (LMS) and Li2Mn0.8Ni0.2SiO4 (LMNS) by ethylene diamine tetra-acetic assisted sol–gel method. In the last method, the two nanoparticles are mixed by hand-milling to form nanocomposites. Synthesized nanoparticles were characterized using X-ray diffraction, Fourier-transform infrared, Raman spectra, scanning electron microscopy, energy-dispersive X-ray spectroscopy, transmission electron microscopy, Brunauer–Emmett–Teller surface area, pL and UV–vis spectra measurements. The nanocomposite presents a well-developed orthorhombic crystal structure with a Pmn21 space group. BET surface area measurements indicate that all the prepared materials are mesoporous. The photocatalytic activity of M3, LMS, LMNS, (LMS/M3), and (LMNS/M3) was investigated b...
Catalysts
Lanthanum (La) nanocomposites LaFeO3, LaNiO3, and LaCoO3 were synthesized using a sol-gel method, and different La to-metal (Fe, Ni, or Co) ratios were attained using various concentrations of salts. The resulting composites were calcined at 540 °C and characterized by XRD, SEM-EDX, FT-IR spectroscopy, XPS, thermogravimetric analysis (TGA), and PL spectroscopy. The activity of the lanthanum composites (LaFeO3, LaNiO3, and LaCoO3) was studied using the photocatalytic degradation of methylene blue (MB) and ortho-toluidine blue (o-TB) under visible light with a wavelength below 420 nm. The change in the concentration of dyes was monitored by using the UV-Vis spectroscopy technique. All composites appeared to have some degree of photocatalytic activity, with composites possessing an orthorhombic crystal structure having higher photocatalytic activity. The LaCoO3 composite is more efficient compared with LaFeO3 and LaNiO3 for both dyes. High degradation percentages were observed for the ...
Photo-catalytic activities of La0.7Ba 0.3MnO3 nanoparticles
Optik, 2020
In this study, the microwave method as a simple and fast method was used to prepare La 0.7 Ba 0.3 MnO 3 (LBMO) nanoparticles. The structural properties of LBMO nanoparticles were studied using X-ray diffraction (XRD) coupled with Rietveld refinement, Transmission Electron Microscopy (TEM) and Energy-dispersive X-ray spectroscopy (EDX). To obtain the calcination temperature, the thermogravimetric analysis (TGA) was carried out. The optical properties of samples were investigated using Ultraviolet-visible spectroscopy (UV-vis). Furthermore, the photocatalyst property of LBMO nanoparticles at different pH has been investigated. The best degradation efficiency obtained at pH-10. The Fourier-transform infrared spectroscopy (FTIR) spectrum was taken before and after photocatalytic activity, by which the perovskite structure of as-prepared samples are confirmed, and no structural change is observed. x Ba x MnO3 (x = 0.3) discussed in this work has the Rhombohedral Crystal structure with R3c space group [9]. In recent years, the utilization of manganites has received remarkable attention in the decolorization process [10-12], due to their appealing optical properties, environmental compatibility and low costs [13-16]. Several synthesis methods, including sol-gel [17], hydrothermal [18], microwave [19], glycine combustion [20], nitrate-complex auto-ignition [21], solid-state [22] have been utilized for synthesis of manganites. In this work, we have synthesized LBMO using the microwave method and subsequently used them as a catalyst in the decolonization process.
Synthesis and characterization of calcium-doped lanthanium nickelates La2−xCaxNiO4+δ ()
Solid State Sciences, 2006
Calcium-doped lanthanum manganite (LCMO) powder was synthesized via hydrothermal method. The structural, morphological and optical properties of the resulting powder was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), inductively coupled plasma-atomic emission spectroscopy (ICP-AES spectrometer), field emission scanning electron microscopy (FESEM) and UV-Vis spectroscopy (UV-Vis). The XRD results showed the existence of only one crystalline phase. FESEM image indicates that the LCMO sample has nanowire structure with an average diameter of ∼125 nm. The band gap energy of the sample was about 2.13 eV. The as-prepared nanowires showed sufficient visible-light photocatalytic activity for the water treatment from dyes and toxic organic materials. The photodegradation efficiency for decolourizing methylene blue solution (7 ppm) by LCMO nanowires (0.07g l −1), after 360 min illumination, was about 73% with a reaction rate constant of 0.003 min −1. The six times cycled results suggested the great long-term stability of the photocatalyst.
Desalination and Water Treatment, 2013
La 0.5 Ca 0.5 CoO 3 perovskite-type oxide is prepared by sol-gel method. The physical and chemical properties of La 0.5 Ca 0.5 CoO 3 were characterized by differential thermal analysis (DTA), X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX), Brunauer-Emmett-Teller (BET) method and IR techniques. The photocatalytic activity of the sample is evaluated by photocatalytic removal of Congo Red (CR) dye under UV light irradiation. The results of XRD and BET indicate that the perovskite-type oxide (LCCO) have a good crystal phase at 650 and 750˚C with large specific surface area. The DTA, XRD, TEM, SEM, and EDX data revealed that LCCO nanoparticles are prepared successfully via sol-gel modified pechini method. The result showed that the degradation efficiency of CR by LCCO is excellent under UV light irradiation under our experiment condition.
Nanomaterials
In this study, we synthesized hybrid systems based on manganese oxide@zinc oxide (Mn3O4@ZnO), using sol gel and hydrothermal methods. The hybrid materials exhibited hierarchical morphologies and structures characterized by the hexagonal phase of ZnO and the tetragonal phase of Mn3O4. The hybrid materials were tested for degradation of methylene blue (MB), methyl orange (MO), and malachite green (MG) under ultraviolet (UV) light illumination. The aim of this work was to observe the effect of various amounts of Mn3O4 in enhancing the photocatalytic properties of ZnO-based hybrid structures towards the degradation of MB, MO and MG. The ZnO photocatalyst showed better performance with an increasing amount of Mn3O4, and the degradation efficiency for the hybrid material containing the maximum amount of Mn3O4 was found to be 94.59%, 89.99%, and 97.40% for MB, MO and MG, respectively. The improvement in the performance of hybrid materials can be attributed to the high charge separation rat...