Mohd Shaban Ansari; Kashif Raees; Elham S. Aazam; M. Z. A. Rafiquee
Abstract
The kinetics of the oxidation of methylene blue (MB) by H2O2 in the presence of iron oxide nanoparticles has been studied. The nanoparticles of iron oxide (Fe3O4) were synthesized and characterized physico-chemical techniques. The XRD studies showed its crystalline nature. The VSM study was carried out ...
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The kinetics of the oxidation of methylene blue (MB) by H2O2 in the presence of iron oxide nanoparticles has been studied. The nanoparticles of iron oxide (Fe3O4) were synthesized and characterized physico-chemical techniques. The XRD studies showed its crystalline nature. The VSM study was carried out to determine the values of the magnetic saturation parameter ~ 40.00 emu/g. The particle were of spherical shape with particle size distribution centered at 12 ± 2 nm. The FT-IR spectra indicated the presence of peaks at 585 cm -1 and 459 cm -1 due to Fe-O bond vibrations. The peak at 3424 cm -1 was assigned to the O-H stretching vibration. The H-O-H bending appeared at 1631 cm -1 . The Fe3O4 nanoparticles enhanced the rate of degradation of MB. The oxidation rate increased with the increase in Fe3O4. At pH 3, the maximum rate of oxidation of MB was observed. The rate of reaction increased with the increase in [H2O2] in the absence of Fe3O4. But in the presence of Fe3O4, the rate constant versus [H2O2] showed peaked behaviour. The CTABr increased the rate of oxidation of MB by H2O2 in the presence of Fe3O4 nanoparticles.
Geitu Yirga; H C Ananda Murthy; Eshetu Bekele
Abstract
Humic acid modified magnetite nanoparticles (HA-Fe3O4 NPs) were synthesized by co-precipitation method by varying the precursor magnetite to HA ratio of 10:1 and 20:1. The synthesized NPs were characterized by FTIR, XRD, SEM-EDX and UV-Vis DR Techniques. The appearance of C=O vibration at 1390 cm -1 ...
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Humic acid modified magnetite nanoparticles (HA-Fe3O4 NPs) were synthesized by co-precipitation method by varying the precursor magnetite to HA ratio of 10:1 and 20:1. The synthesized NPs were characterized by FTIR, XRD, SEM-EDX and UV-Vis DR Techniques. The appearance of C=O vibration at 1390 cm -1 confirms positive interaction of carboxylate anion of HA and Fe3O4. The XRD pattern and SEM image shows bare Fe3O4 and HA-Fe3O4 (10:1 and 20:1) exhibit cubic spinel structure and the spherical shape morphology, respectively. The crystallite sizes of NPs were found to be 11.50 nm, 9.17 nm and 12.65 nm for bare, 10:1 and 20:1 Fe3O4-NPs, respectively. The adsorption capacity for the dye was found to increase with increase in contact time, adsorbent dose and initial pH of the solution. The result was best fitted to pseudo 2 nd order kinetics model and Langmuir isotherm model. The methylene blue (MB) removal efficiency of bare, 10:1 and 20:1 Fe3O4-NPs from aqueous solutions was recorded to be 95.8%, 99.4%, and 97.6%, respectively. The study confirms the greater efficiency of HA-Fe3O4 NPs compared to bare Fe3O4 for the removal of MB dye. The MB removal efficiency of HA-Fe3O4 NPs was found to be proportional to amount of adsorbed HA. Copyright © VBRI Press.
Abdul Rauf Khaskheli; Saba Naz; Razium Ali Soomro; Faruk Ozul; Abdalaziz Aljabour; Nazar Hussain Kalwar; Abdul Waheed Mahesar; Imren Hatay Patir; Mustafa Ersoz
Abstract
This report demonstrates a facile and green fabrication method for the nickel nanoparticles using L-lysine as an efficient protecting agent. The application of green amino acid (L-lysine) enabled formation highly spherical and well-dispersed nanoparticles with average diameter in the range of 10 ±2.5 ...
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This report demonstrates a facile and green fabrication method for the nickel nanoparticles using L-lysine as an efficient protecting agent. The application of green amino acid (L-lysine) enabled formation highly spherical and well-dispersed nanoparticles with average diameter in the range of 10 ±2.5 nm. UV-Vis spectroscopy was used as a primary tool to elaborately study and optimize the necessary experimental condition for the developed synthetic protocol. Fourier transform infrared spectroscopy (FTIR) was used to confirm the surface protection of Ni NPs via L-lysine molecules whereas; atomic force microscopy (AFM) and scanning electron microscopy (SEM) provided morphological and topographical view of the as-synthesized Ni NPs. In addition, small angle X-ray scattering (SAXS) and X-ray diffraction (XRD) were used to evaluate compositional characteristics of fabricated L-lysine protected Ni NPs. The as-synthesized Ni NPs demonstrated excellent catalytic potential when utilized as heterogeneous catalyst for reduction of methylene Blue (MB) in the presence of sodium borohydride (NaBH4). The observed catalytic reaction was determined to follow pseudo first order kinetics with rate constant (K) and turn over frequency (TOF) determined to be 0.0224 and TOF value of 0.00411 s -1 respectively.
Sini Kuriakose; Biswarup Satpati; Satyabrata Mohapatra
Abstract
ZnO nanostructures were synthesized by a facile wet chemical method using water, ethanol and propanol as solvents. X-ray diffraction, field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) have been used to study the structural properties of the synthesized ZnO ...
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ZnO nanostructures were synthesized by a facile wet chemical method using water, ethanol and propanol as solvents. X-ray diffraction, field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) have been used to study the structural properties of the synthesized ZnO nanostructures, while their optical properties have been studied using UV-visible absorption spectroscopy and Raman spectroscopy. The photocatalytic activities of the as-synthesized ZnO nanostructures were evaluated by monitoring sunlight driven photocatalytic degradation of methylene blue (MB) and methyl orange (MO) dyes in water and it was observed that ZnO nanostructures prepared using propanol as a solvent exhibit highly enhanced photocatalytic activity as compared to those prepared using other solvents. The mechanism underlying the photocatalytic activity of ZnO nanostructures towards photocatalytic degradation of dyes is proposed. We attribute the highly enhanced photocatalytic activity of ZnO nanostructures prepared in propanol to the high surface area of nanosheets-like structures formed, which lead to enhanced adsorption of dye molecules resulting in efficient photocatalytic degradation of dyes upon sunlight irradiation.
Jaspal Singh; Satyabrata Mohapatra
Abstract
Nanostructures of TiO2 were synthesized by a facile sol-gel method using pentanol as solvent. The effects of thermal annealing on the structural, optical and photocatalytic properties of as-synthesized TiO2 nanostructures have been studied using X-ray diffraction (XRD), atomic force microscopy (AFM), ...
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Nanostructures of TiO2 were synthesized by a facile sol-gel method using pentanol as solvent. The effects of thermal annealing on the structural, optical and photocatalytic properties of as-synthesized TiO2 nanostructures have been studied using X-ray diffraction (XRD), atomic force microscopy (AFM), Raman spectroscopy and UV-visible absorption spectroscopy. XRD and Raman spectroscopy results revealed that the synthesized TiO2 nanostructures exist in anatase phase for annealing at temperatures up to 300 o C, while annealing at 600 o C led to the formation of TiO2 nanostructures in anatase/rutile mixed-phase. AFM studies revealed the presence of TiO2 nanorods, which showed a small decrease in aspect ratio upon annealing. The photocatalytic activity of nanostructured TiO2 samples was evaluated through sun light driven degradation of methylene blue (MB) dye in water. TiO2 nanorods in anatase/rutile mixed-phase in the sample annealed at 600 o C were found to exhibit the highest photocatalytic activity towards degradation of MB dye. The mechanism underlying the enhanced photocatalytic activity of TiO2 nanostructures in anatase/rutile mixed-phase is tentatively proposed.
K. Chennakesavulu; G. Ramanjaneya Reddy; S. Sanjeevi Prasath; S. Supriya; S. Sivanesan
Abstract
In-situ synthesis of ZnO and Nb2O5 composites was carried out in alkaline medium. The obtained composites were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, diffuse reflectance UV-Vis spectrophotometer (DRS), Powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy ...
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In-situ synthesis of ZnO and Nb2O5 composites was carried out in alkaline medium. The obtained composites were characterized by Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, diffuse reflectance UV-Vis spectrophotometer (DRS), Powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Brunauer-Emmett-Teller (BET) surface area method, N2-sorption isotherms, Thermo gravimetric analysis (TGA), Particle size and Field emission scanning electron microscopy (FESEM/EDX). The synthesized composite was used as photocatalyst in the degradation of reactive red-198 (RR), methylene blue (MB) and 3-chloro phenol (3CP) under visible light irradiation. The catalytic activity and removal percentage of dye was determined by the spectrophotometric method, it indicates high percentage of degradation for the ZnO:Nb2O5 composite. The kinetic parameters were found to obey pseudo-first order oxidation reaction, which may be due to the fixed amount of the catalyst and concentration of the dye solution. The recycled and purified composites of ZnO:Nb2O5 was tested the catalytic activity and was compared with that of the fresh catalyst.
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