Aplicação do processo foto-eletro-Fered-Fenton no tratamento de águas residuais de laboratório de anatomia

Abstract

Formaldehyde (HCHO) is a preservative widely used in anatomy laboratories due to its high efficiency in preserving parts used in practical classes. However, the large volume of storage tanks for anatomical parts results in the generation of a considerable amount of concentrated effluent containing this substance (ECF), which requires careful storage, as well as the development of technologies for its treatment, since formaldehyde has harmful effects to workers and students in the laboratory, such as irritation of the airways, eyes and skin, or even the development of serious diseases such as cancer, according to the International Agency for Research on Cancer (USA). Some works approach the treatment of synthetic or real effluents of HCHO, however, in high concentrations (> 12500 mg L-¹) these effluents are not biodegradable and require advanced treatment processes. Initially, preliminary tests were carried out and, through a response surface methodology, the experimental conditions of the process were improved, obtaining the following responses: pH 4.5, electric current 2.4 A and [H2O2] = 24000 mg L−1, for an effluent with [HCHO]0 = 13478 mg L−1, [TOC]0 = 54353 mg L−1 Within this context, this work investigated the degradation and mineralization of HCHO by the photo-electro-Fered-Fenton process on a laboratory scale. Three treatment strategies were then evaluated: anodic oxidation → O3 → H2O2; anodic oxidation → H2O2 → O3; anodic oxidation → H2O2 → O3 (no electrical current). Under these conditions, degradation and mineralization values of HCHO and TOC of 90% and 85%, respectively, were achieved, in addition to the reduction of toxicity levels against the bioindicator Artemia salina.