Aperfeiçoamento do protocolo de tratamento de resíduos de DNS

Abstract

The 3, 5-dinitrosalicyclic acid (DNS, formula ), according to the literature is an aromatic compound commonly used in quantification of carbohydrates and enzymatic assays. The DNS is used to perform the enzymatic kinetics evaluation of the hydrolysis of sucrose catalyzed by invertase and also determinate total reducing sugar, performed at the didactic laboratories of the School of Chemical Engineering/UFU. At the end of the experiments, much residue is generated so there is a need of treatment of the effluent becames urgent. It was proposed to improve the current protocol by studying the possibility of DNS degradation by an Advanced Oxidative Process (AOP) utilizing photocalysis reaction in a heterogeneous system with titanium dioxide and zinc oxide as catalysts (semiconductors) together with ultraviolet light, rather than a homogeneous system. In this context, two experimental conditions were executed: i) only the action of ultraviolet light (photolysis), in the DNS degradation process and ii) the evaluation of the influence of the combination (TiO2/ZnO/UV) for DNS degradation. In both cases the complete degradation of the DNS residue was observed. In addition, the formation of active intermediates was suggested in the photocatalysis, however in similar investigations involving the same catalysts was suggested that these intermediates are less toxic than the initial contaminant, a fact to be studied in future works.