Performance of steel wool residue as an iron source for the photo-Fenton process in pharmaceuticals degradation

Anti-inflammatories are drugs that currently can be found in effluents and, as a consequence, in surface and groundwater. Therefore, this work aimed to evaluate the efficiency of advanced oxidative processes in the degradation of the drugs ketoprofen, tenoxicam and meloxicam, aiming application in wastewater treatment. The system studied was photo-Fenton peroxidation under artificial sunlight radiation (iron source: ferrous sulfate or steel wool residue). The working conditions for the system with residue were 1.25 and 300 mg center dot L-1 of ferrous and oxidant, and pH approximate to 2.5. The degradation kinetics was monitored by ultraviolet visible spectrophotometer and the experimental data by it represented by the model of by Nichela and collaborators. After 90 min, the systems achieved a degradation greater than 82%, monitoring the wavelength of 260 nm, and greater than 96%, at 367 nm. In synthetic effluent, the chemical oxygen demand was reduced by 89% after 270 min, obtaining a good fit to Nichela and collaborators model. Through liquid chromatography and toxicity tests (it was verified the degradation of the original compounds and formation of more toxic intermediates, in relation to the aqueous solution. Analisando de forma conjunta dos dados das analises cromatograficas com os testes de toxicidade, utilizando moluscos, verificou-se a degradacao dos compostos originais, com formacao de intermediarios. Seeking a way to reduce toxicity, considering the results obtained for the artificial solar radiation, the use of the natural one is proposed due to its high availability that combined with the use of waste reduces the costs of the process, making it a viable alternative for treating contaminated water.