Powder and Nanotubes Titania Modified by Dye Sensitization as Photocatalysts for the Organic Pollutants Elimination.

Julie Murcia,Svetlana Ivanova,Hugo Rojas,Elsa Ávila-Martínez,Oscar Laguna,Jairo Cubillos,Anna Penkova

doi:10.3390/nano9040517

Abstract

In this study, titanium dioxide powder obtained by the sol-gel method and TiO2 nanotubes, were prepared. In order to increase the TiO2 photoactivity, the powders and nanotubes obtained were modified by dye sensitization treatment during the oxide synthesis. The sensitizers applied were Quinizarin (Q) and Zinc protoporphyrin (P). The materials synthesized were extensively characterized and it was found that the dye sensitization treatment leads to modify the optical and surface properties of Titania. It was also found that the effectiveness of the dye-sensitized catalysts in the phenol and methyl orange (MO) photodegradation strongly depends on the dye sensitizer employed. Thus, the highest degradation rate for MO was obtained over the conventional Q-TiO2 photocatalyst. In the case of the nanotubes series, the most effective photocatalyst in the MO degradation was based on TiO2-nanotubes sensitized with the dye protoporfirin (ZnP). Selected catalysts were also tested in the phenol and MO photodegradation under visible light and it was observed that these samples are also active under this radiation.

Highlights

As a result of the industrial and human activities, large volumes of wastewater containing different pollutants are poured every year, significantly affecting the environmental stability
The materials synthesized were extensively characterized and it was found that the dye sensitization treatment leads to modify the optical and surface properties of Titania
It was found that the effectiveness of the dye-sensitized catalysts in the phenol and methyl orange (MO) photodegradation strongly depends on the dye sensitizer employed

Summary

Introduction

As a result of the industrial and human activities, large volumes of wastewater containing different pollutants are poured every year, significantly affecting the environmental stability. For the treatment of urban and industrial wastewater, different alternatives have been employed. Phenolic compounds and dyestuffs are common organic pollutants in wastewater, which have proven to be hard to remove. With this outlook, currently, it is necessary to search for more suitable and effective methods for environmental pollutants removal. TiO2 photocatalysis has been successfully applied as an eco-friendly and efficient alternative in the treatment of wastewater sources and polluted atmospheres [3,4,5,6,7,8,9,10,11,12]. TiO2 has been considered as the best photocatalyst, the photoactivity of this oxide depends on its physicochemical properties and on its structure

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