Photosensitised Degradation of Organic Dyes by Visible Light Using Riboflavin Adsorbed on the Surface of TiO₂Nanotubes

Abstract

A degradação de soluções aquosas de índigo carmim (IC), azul de metileno (MB) e laranja de metilo (MO) assistida pela luz visível foi conseguida sobre a superfície de nanotubos (NTs) de TiO 2 impregnados com riboflavina (RF). Soluções aquosas diluídas de RF na presença de RF-NTs TiO 2 irradiados com luz UV produziram O 2 , CO e CO 2 como principais produtos gasosos. As mesmas soluções quando irradiadas com luz visível mostraram que o O 2 foi o produto principal obtido. Esta geração de O 2 in situ com luz visível permite a degradação dos corantes, sem a necessidade de borbulhar ar ou oxigênio no sistema de reação. A degradação fotocatalítica de MO, MB e IC pode ser descrita por um modelo de cinética de pseudo-primeira ordem obtendo ca. 100% de degradação de MB, MO e IC em menos de 3 h de iluminação de luz visível. Os resultados aqui apresentados são altamente promissores em vista da potencial aplicação dos catalisadores RF-TiO 2 NTs preparados com dois compostos ambientalmente corretos na degradação de poluentes utilizando radiação solar.Visible light-assisted degradation of indigo carmine (IC), methylene blue (MB) and methyl orange (MO) aqueous solutions has been achieved on the surface of TiO 2 nanotube (NT) arrays impregnated with riboflavin (RF). Diluted RF water solutions in the presence of RF-TiO 2 NTs irradiated with UV light produced O 2 , CO and CO 2 as main gas products. On the contrary, the same solutions irradiated with visible light evolved O 2 as a main product. This in situ O 2 generation under visible light absorption allows the degradation of the dyes without the necessity to bubble air or oxygen in the reaction system The photocatalytic degradation of MO, MB and IC can be described by a pseudo-first-order kinetic model obtaining ca. 100% degradation of MB, MO and IC in less than 3 h of visible light illumination. The results provided here are highly promising in view of various photocatalytic applications of the prepared RF-TiO 2 NTs catalysts by two environmentally friendly compounds in the degradation of pollutants using solar radiation.

Curcumin‐Functionalized Ag/Ag2O Nanocomposites: Efficient Visible‐Light Z‐scheme Photocatalysts

“…The value of y is found to be zero for this catalyst sample. This is in contrast to majority of first‐order aerobic MO degradation reports available in literature . Following this, Fig.…”

Visible light sensitization of TiO2/Ag/N nanostructures synthesized by microwave irradiation for oxidative degradation of organic dyes

“…In the present work, we extend our previous investigations on the synthesis of new photocatalysts [8,[40][41][42][43]. The TiO 2 NTs, TiO 2 NPs, and Ag NPs were prepared using a green microwave-assisted method.…”

Riboflavin-Immobilized CeO2–RGO Nanohybrid as a Potential Photoredox Catalyst for Enhanced Removal of Organic Pollutants under Visible Light

“…Therefore, the heterogeneous system is more flexible and advantageous due to its high durability, facile recovery, and easy separation of the catalyst. Only a few reports describe the utilization of RF in a heterogeneous medium under UV and visible light irradiations. − Here, we aimed to make a riboflavin-modified heterogeneous system for visible light-assisted photocatalytic applications. An attempt was made to synthesize CeO 2 nanoparticles with controlled morphology by a modified procedure using poly­(vinylpyrrolidone) (PVP) as a template.…”