Synthesis of TiO₂ supported on clay for degradation of dye yellow eosin

Full text: Industrial development raises concerns about the discards and risks that dyes, pesticides and pharmaceuticals can cause to humans and the environment. Thus, several methods have been extensively studied and employed for the removal of contaminants, such as adsorption, filtration, coagulation and flocculation, membrane adsorption, and photocatalysis. Among these methods researchers have shown that photocatalysis has the potential to treat effluents containing organic compounds due to their low cost, low energy consumption, and the ability to convert pollutants into harmless final products such as CO₂, H₂O. The photocatalysis using TiO₂ has the most used in relation to the other semiconductors studied due to its high catalytic potential, hydrophilicity, low cost, stability. However, the low surface area and difficult removal of TiO₂ in aqueous solution is a disadvantageous feature. Despite this, recent studies show that the efficiency of TiO₂ can be improved when the oxide is supported in other materials. The aim of the present work was incorporate TiO₂ by the sol-gel method in the Palygorskite clay to be used in the aqueous solution decontamination and to evaluate its photocatalytic efficiency. The materials were characterized by XRD, SEM and FTIR. Photocatalytic activity was evaluate dusing the EA (Yellow Eosin) dye. The photodegradation was carried out in a radiation box using mercury vapor of 125 W without bulb, a borosilicate reactor, a 25°C. The SEM images, XRD diffractograms and the FTIR spectra showed the presence of the TiO₂ anatase planes and bands, confirming their incorporation in the clay using the sol gel technique. The PALT-400 composite obtained a dye degradation rate of 62.38% at the maximum irradiation time. The difference of 37.69% degradation rate in relation to PAL-p is due to TiO₂ in the clay. (author)