Solar Photocatalytic Degradation Of Tartrazine Using Titanium Dioxide

Abstract

As wastewater treatments become more important nowadays, photocatalysis, an alternative wastewater treatment method, shows a promising potential. By now, many studies on the photocatalytic destruction of single organic contaminants have been carried out. However, its application to the detoxification of samples of contaminants mixtures with high Total Organic Carbon levels has not been thoroughly investigated. Although presently many treatment methods are being used, most of them do not completely destroy the pollutants but only offer phase transfer or partial degradation of the pollutants. On the other hand, solar photocatalytic process is an exciting clean technology that uses only sunlight, water, and a reusable catalyst to remove toxins or pollutants from water. In a photocatalytic process, a semiconductor photocatalyst is activated with ultraviolet (UV) irradiation from the sun. The activated photocatalyst promotes the formation of hydroxyl radicals, which in turn completely degrade the pollutants. In this study, the photocatalyst used was titanium dioxide (TiO2) and tartrazine was chosen as the pollutant. Tartrazine is one of the popular water soluble dyes used in food coloring industries but it is carcinogenic at high concentration. The photocatalytic experiments were conducted with varying catalyst loading (0–1.5 g/L), initial concentration (5–35 ppm), and flowrate of tartrazine solution (1.0–1.5 L/min). The dye solution was exposed to sunlight for about two hours. The experimental results showed that a considerable increase in the degradation efficiency of the tartrazine-compound could be obtained by a combination of TiO2 and solar light. The optimum catalyst weight loading for the degradation of tartrazine dye was found to be 1.0 g/L. The initial concentration of the tartrazine dye and flowrate of tartrazine solution were found to effect the degradation efficiency of the dye. Higher initial concentration resulted in lower degradation efficiencies, while higher tartrazine solution flowrate resulted in higher degradation efficiency.