Otimização da degradação do antibiótico cloridrato de tetraciclina utilizado em processos oxidativos avançados

Abstract

In the present work was carried out the study of oxidative degradation of tetracycline, an antibiotic in common use that by its characteristics, can represent a wide range of medicines. The first phase of the work consisted in the preparation of Tetracycline hydrochloride solution at a concentration of 30 mgL-1. The experiments by oxidative processes advanced (Fenton process) were carried out in a cylindrical reactor glass (250 mL) over 30 minutes, the room temperature and without the presence of light. The agitation of the system was provided by the use of a magnetic stirrer. Ferrous sulphate heptahydrate was used as a source of iron ions and hydrogen peroxide as oxidizer for the process. The concentration of tetracycline hydrochloride was determined by using a UV-vis spectrophotometer. The results for the oxidative process showed that the degradation of the antibiotic was quite fast. Experiments to study of the reactions of the process batch were carried out, according to statistical factorial planning (23), which investigated the influence of three variables (pH, concentration of ferrous ions and hydrogen peroxide). Statistical analysis indicated that all variables were significant in the process and that the pH of the reaction has an important negative effect on degradation of the antibiotic. It was found that the more favourable conditions degradation were: pH 2,0, [H2O2] 50 mgL-1and [Fe2+] 10 mgL-1. Under these conditions, after 30 minutes of reaction and 25ºC, it was possible to achieve about 80% of degradation of the antibiotic.