Degradação do azul de metileno por fotocatálise heterogênea utilizando ZnO como catalisador

Abstract

The textile industry is a sector that has been growing over the years and the search for processes with less emission of pollutants has been a challenge. Several treatments are being studied with the aim of transforming the contaminants into safe or less toxic compounds. In this context, the Advanced Oxidative Processes is been used and they are based on hydroxyl radical generation and can generate mineralized final products. Heterogeneous photocatalysis is a promising advanced oxidative process in the elimination of toxic compounds. This process involves the use of a photocatalyst (semiconductor), such as zinc oxide (ZnO) in suspension or immobilized in solution activated by ultraviolet radiation. This work aims to the degradation of the methylene blue dye by heterogeneous photocatalysis using ZnO immobilized on alginate spheres as catalyst, optimizing parameters such as catalyst concentration, pH, concentration of the dye solution and reuse. The experiment was performed in a jacketed beaker coupled to a thermostatic bath found inside a photocatalytic reactor containing mercury vapor lamp. Immobilization of the catalyst on the alginate beads was performed in a peristaltic pump. Studies indicated that there was no significant difference between 10 and 20 g L-1 concentration, so the use of the 10 g L-1 catalyst was chosen. The influence of the pH was not significant and the same was verified with the effect on the variation of the concentration, since these were small variations.