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Micelle-assisted synthesis of Al2O3·CaO nanocatalyst: optical properties and their applications in photodegradation of 2,4,6-trinitrophenol.

Imtiaz A, Farrukh MA, Khaleeq-ur-rahman M, Adnan R - ScientificWorldJournal (2013)

Bottom Line: The as-synthesized nanocatalysts were further used as substrate for the synthesis of alumina doped calcium oxide (Al2O3·CaO) nanocatalysts via deposition-precipitation method at the isoelectric point of CaO.The Al2O3·CaO nanocatalysts were characterized by FTIR, XRD, TGA, TEM, and FESEM techniques.The direct optical band gap of the Al2O3·CaO nanocatalyst was found as 3.3 eV.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, GC University Lahore, 54000 Lahore, Pakistan.

ABSTRACT
Calcium oxide (CaO) nanoparticles are known to exhibit unique property due to their high adsorption capacity and good catalytic activity. In this work the CaO nanocatalysts were prepared by hydrothermal method using anionic surfactant, sodium dodecyl sulphate (SDS), as a templating agent. The as-synthesized nanocatalysts were further used as substrate for the synthesis of alumina doped calcium oxide (Al2O3·CaO) nanocatalysts via deposition-precipitation method at the isoelectric point of CaO. The Al2O3·CaO nanocatalysts were characterized by FTIR, XRD, TGA, TEM, and FESEM techniques. The catalytic efficiencies of these nanocatalysts were studied for the photodegradation of 2,4,6-trinitrophenol (2,4,6-TNP), which is an industrial pollutant, spectrophotometrically. The effect of surfactant and temperature on size of nanocatalysts was also studied. The smallest particle size and highest percentage of degradation were observed at critical micelle concentration of the surfactant. The direct optical band gap of the Al2O3·CaO nanocatalyst was found as 3.3 eV.

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Plot of ln⁡(A–A∞) versus time for the oxidation of 2,4,6-TNP with (a) CaO and (b) Al2O3·CaO nanocatalysts prepared under different concentrations of surfactant.
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fig12: Plot of ln⁡(A–A∞) versus time for the oxidation of 2,4,6-TNP with (a) CaO and (b) Al2O3·CaO nanocatalysts prepared under different concentrations of surfactant.

Mentions: A mixture of 5 mg of CaO nanocatalysts and 25 mL solution of 2,4,6-TNP (15 ppm) was placed under UV irradiation with constant stirring for 15 minutes at ambient temperature. On the basis of Beer-Lambert law, calibration was done for 2,4,6-TNP at a wavelength of maximum absorptivity, λmax⁡, 356 nm [53]. The catalytic activity was determined using UV Spectrophotometer (UV-1700 Shimadzu) by measuring the change in absorbance at 356 nm every 60-second interval. Same procedure was adopted to determine catalytic activity of Al2O3·CaO nanocatalysts against 2,4,6-TNP [54]. The analysis of samples showed a continuous decrease in absorption at λmax⁡ = 356 nm, which was used to track the degradation of 2,4,6-TNP [55]. It is evident that reaction kinetics of both CaO (Figure 12(a)) and Al2O3·CaO (Figure 12(b)) nanocatalysts with 2,4,6-TNP follows first order. The first order rate constant values, k′, were determined from the slope of the graphs as shown in Figures 12(a) and 12(b).


Micelle-assisted synthesis of Al2O3·CaO nanocatalyst: optical properties and their applications in photodegradation of 2,4,6-trinitrophenol.

Imtiaz A, Farrukh MA, Khaleeq-ur-rahman M, Adnan R - ScientificWorldJournal (2013)

Plot of ln⁡(A–A∞) versus time for the oxidation of 2,4,6-TNP with (a) CaO and (b) Al2O3·CaO nanocatalysts prepared under different concentrations of surfactant.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3842055&req=5

fig12: Plot of ln⁡(A–A∞) versus time for the oxidation of 2,4,6-TNP with (a) CaO and (b) Al2O3·CaO nanocatalysts prepared under different concentrations of surfactant.
Mentions: A mixture of 5 mg of CaO nanocatalysts and 25 mL solution of 2,4,6-TNP (15 ppm) was placed under UV irradiation with constant stirring for 15 minutes at ambient temperature. On the basis of Beer-Lambert law, calibration was done for 2,4,6-TNP at a wavelength of maximum absorptivity, λmax⁡, 356 nm [53]. The catalytic activity was determined using UV Spectrophotometer (UV-1700 Shimadzu) by measuring the change in absorbance at 356 nm every 60-second interval. Same procedure was adopted to determine catalytic activity of Al2O3·CaO nanocatalysts against 2,4,6-TNP [54]. The analysis of samples showed a continuous decrease in absorption at λmax⁡ = 356 nm, which was used to track the degradation of 2,4,6-TNP [55]. It is evident that reaction kinetics of both CaO (Figure 12(a)) and Al2O3·CaO (Figure 12(b)) nanocatalysts with 2,4,6-TNP follows first order. The first order rate constant values, k′, were determined from the slope of the graphs as shown in Figures 12(a) and 12(b).

Bottom Line: The as-synthesized nanocatalysts were further used as substrate for the synthesis of alumina doped calcium oxide (Al2O3·CaO) nanocatalysts via deposition-precipitation method at the isoelectric point of CaO.The Al2O3·CaO nanocatalysts were characterized by FTIR, XRD, TGA, TEM, and FESEM techniques.The direct optical band gap of the Al2O3·CaO nanocatalyst was found as 3.3 eV.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, GC University Lahore, 54000 Lahore, Pakistan.

ABSTRACT
Calcium oxide (CaO) nanoparticles are known to exhibit unique property due to their high adsorption capacity and good catalytic activity. In this work the CaO nanocatalysts were prepared by hydrothermal method using anionic surfactant, sodium dodecyl sulphate (SDS), as a templating agent. The as-synthesized nanocatalysts were further used as substrate for the synthesis of alumina doped calcium oxide (Al2O3·CaO) nanocatalysts via deposition-precipitation method at the isoelectric point of CaO. The Al2O3·CaO nanocatalysts were characterized by FTIR, XRD, TGA, TEM, and FESEM techniques. The catalytic efficiencies of these nanocatalysts were studied for the photodegradation of 2,4,6-trinitrophenol (2,4,6-TNP), which is an industrial pollutant, spectrophotometrically. The effect of surfactant and temperature on size of nanocatalysts was also studied. The smallest particle size and highest percentage of degradation were observed at critical micelle concentration of the surfactant. The direct optical band gap of the Al2O3·CaO nanocatalyst was found as 3.3 eV.

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