TiO₂-Coated Cenospheres as Catalysts for Photocatalytic Degradation of Methylene Blue, p-Nitroaniline, n-Decane, and n-Tridecane under Solar Irradiation

Abstract

Fly ash cenosphere particles generated in coal-fired thermal power plants were coated with TiO 2 using the sol-gel technique. Thus prepared photocatalysts were used for the degradation of methylene blue (MB), nitro-aromatic compound p-nitroaniline (PNA), and photocatalytic oxidation of n-decane and n-tridecane from aqueous solution under solar light irradiation. The morphology, composition, and crystallinity of both pristine and TiO 2 -coated cenospheres were studied. The UV-visible spectroscopic analysis was used to monitor the progress of the reaction for MB and PNA. The decrease in the amount of n-decane and n-tridecane was determined by gas chromatographic analysis. The decrease in the concentration for a 25 ppm initial concentration of MB and PNA was observed to be 99 and 26%, respectively, after 3 h of reaction time. This demonstrates that MB is more amenable toward degradation and mineralization as it acts as a sensitizer. Decreases up to 51 and 36% for n-decane and n-tridecane were observed with initial amounts of 3-12 mL, respectively, after 6 h. The coated cenosphere catalyst could be recovered by filtration and reused. The coating was found to be stable even after three uses of the catalyst in the photocatalytic degradation reaction of MB and PNA. The mineralization of dye and nitro-aromatic compound was confirmed by the chemical oxygen demand analysis. Cenospheres, because of their light weight, would make the catalyst particles float on the aqueous surface and hence could be directly activated by sunlight.

Characterization of Fly Ash Cenospheres Produced from the Combustion of Ekibastuz Coal

“…53 As a result, the cenospheres have an additional advantage in the development of functional materials, such as microspherical membranes, 15,16 composite sorbents, 18,19 and supported catalysts. 23 Table 4. SEM images illustrate that, with an increase in the Al 2 O 3 content, the structure of the globules changes.…”

Functional Modification with TiO2 Nanoparticles and Simultaneously Dyeing of Wool Fibers in a One-Pot Hydrothermal Process

“…The size of TiO 2 particles, synthesized by taking Ti(OC 4 H 9 ) 4 as the precursor in the presence of dye, is observed to be less than 10 nm (Figure 2a), which is agreement with the particle size measured in XRD analysis. It is also indicated in HRTEM image that the resolved lattice spacing is of 0.347 nm (Figure 2b 18 which is corresponding to the index of crystal planes identified in XRD analysis.…”

Degradation and mineralization of aqueous nitrobenzene using ETS-4 photocatalysis

“…The photocatalytic decomposition of organic compounds especially from aqueous media has attracted a great deal of attention [7,[18][19][20][21][22][23][24]. The supporting semiconductor catalysts particularly titania catalyst on silica [25,26], zeolites [27][28][29], fibre glass [30,31], electrode [32] and cenospheres [33] have also been studied to enhance the photocatalytic activity. However, catalyst recovery due to the leaching of active species remains a challenge even of supported photocatalysts.…”