Ultrasound assisted synthesis of Fe‐TiO₂ and Ce‐TiO₂ catalysts and subsequent application for photocatalytic, sonocatalytic, and sonophotocatalytic decolorization of basic Victoria blue dye

Abstract

Synthesis of Fe‐TiO2 and Ce‐TiO2 catalysts using conventional, and ultrasound assisted (US) homogeneous coprecipitation method has been investigated. Effects of ultrasonic irradiation time and ultrasonic power on catalyst synthesis were studied and it was elucidated that best conditions were 140 W and 60 min, respectively. Characterization using FE‐SEM revealed spherical particles with the size range from 36.4 to 49.4 nm whereas XRD analysis affirmed a mixture of anatase, rutile, and brookite TiO2 phase with crystallite size ranging from 4.18 to 12.99 nm. BET analysis revealed highest specific surface area (211.59 m2/g) for the sonochemically synthesized Ce‐TiO2. The process intensification benefits demonstrated in catalyst synthesis were better crystallinity, lower particle size, and higher surface area. The application of catalyst efficacy was tested for photocatalytic, sonocatalytic, and sonophotocatalytic oxidation where maximum decolorization as 71.97% was obtained for sonochemically synthesized Ce‐TiO2 applied in the sonophotocatalytic approach. Studies related to regeneration, stability, and leaching of Ce and Ti ion from the sonochemically synthesized Ce‐TiO2 catalyst were also performed. It was observed that the catalyst can be regenerated easily and there were no structural changes in the catalyst after regeneration with negligible leaching of the ions from the catalyst into the solution. Overall, an improved process for catalyst synthesis with intensified decolorization application was demonstrated based on the use of ultrasound.

Recent progress on sonochemical production for the synthesis of efficient photocatalysts and the impact of reactor design

“…Dey and Gogate [68] , investigated the effect of the synthesis method of Fe-TiO 2 and Ce-TiO 2 structures. A conventional (C) and an ultrasound assisted (US) homogeneous coprecipitation method was used and it was observed that the intensification improves the crystallinity, lowers the particle size (1270 and 1170 nm for Ce-TiO 2 (C) and Fe-TiO 2 (C), and 584 and 449 nm for the Ce-TiO 2 (US) and Fe-TiO 2 (US), respectively) and increases the surface area of the catalyst in the case of Ce-TiO 2 (US) (185.65 m 2 /g).…”

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Fig. 6 FESEM images of catalysts obtained using different approaches (a) Ce-TiO 2 (C), (b) Ce-TiO 2 (US), (c) Fe-TiO 2 (C), (d) Fe-TiO 2 (US) [68] .

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Sonocatalytic degradation of nitrobenzene with metal oxide clay nanocomposites

“…2 Although there are different physical and chemical treatment methods available that have been reviewed for the treatment of wastewater, they are associated with different performance characteristics, generation of secondary wastes and high treatment costs. [3][4][5] In recent times, advanced oxidation processes (AOPs) have been extensively studied for the degradation of various pollutants as they mainly produce hydroxyl radicals ( • OH) also resulting in the formation of superoxide radicals (O 2…”

“…Moreover, in many developing countries, the bulk of domestic and industrial wastewater is directly discharged into natural streams without any treatment processes or after primary treatment only as a consequence of high treatment costs, causing severe health and environmental concerns 2 . Although there are different physical and chemical treatment methods available that have been reviewed for the treatment of wastewater, they are associated with different performance characteristics, generation of secondary wastes and high treatment costs 3‐5 . In recent times, advanced oxidation processes (AOPs) have been extensively studied for the degradation of various pollutants as they mainly produce hydroxyl radicals ( • OH) also resulting in the formation of superoxide radicals (O 2 •− ) and hydroperoxyl radicals ( • OOH), driving the degradation of pollutants 6,7 .…”