Degradação de sacarose através de fotocatálise heterogênea com uso de radiação solar

Abstract

The heterogeneous photocatalysis, one of the Advanced Oxidation Process (AOP), has been pointed out as an efficient way to degrade organic components present in industrial and domestic effluents. In face of the increasingly poor quality of water in the world and the high potential of Natal, in Rio Grande do Norte, for the application of that technology, that work studies the degradation of sucrose in an aqueous solution using the heterogeneous photocatalysis. Then, it tried to determine the quantity of sucrose degraded, the kinetics of the reaction and the influence of pH and initial concentration of substrate on the efficiency of the process. Therefore, it were realized reactions of heterogeneous photocatalysis using solar light, titanium oxide and solutions of sucrose with initial concentrations of 30% and 20% (w/w). The more concentrated solution was submitted to reactions at high pH (9,0), medium pH (6,5) and low pH (5,0), while the solution of 20% was submitted to reactions at pH equals to 6,5. The product analysis was made with a refractometer, which was also used to obtain an empiric equation that relates refractive index and concentration of sugar. It was observed that there was no degradation of sucrose when its initial concentration (C0) was 20%, either in the case of concentration equal to 30% in basic medium (pH = 9,0). However, when the pH was equal to 6,5 and 3,0 (C0 = 30%), the degradation was, respectively, equal to 2,35% and 4,45% in relation to the initial concentration. Therefore, lower concentrations of substrate may negatively affect the efficiency of heterogeneous photocatalysis, while lower pH’s may increase its efficiency. Because of the low values of degradation observed, it was not possible to establish the kinetics of the reaction.