Avaliação da toxicidade e formação de subprodutos do processo foto-fenton induzido com complexante orgânico no tratamento de lixiviado de aterro sanitário

Abstract

The present work addresses the treatment of landfill leachate by the previously optimized photo-Fenton advanced oxidation process induced by the complexing agent oxalic acid. The applied experimental conditions were: solution pH 7.8, 90 mg Fe3+ L-1 and 500 mg H2O2 L-1, within the accumulated energy range of 0 to 7.3 kJ L-1. The kinetic removal results obtained were 51,1 and 50,05% for color and Abs 254 nm, respectively. An analysis via gas chromatography–mass spectrometry identified a large variety of toxic compounds present in the untreated leachate, such as Bisphenol A and Diamylphthalate, indicating a high polluting potential. Most of these pollutants were degraded and/or reduced to compounds of simpler structure by the photo-Fenton, as indicated by the significant reduction of compounds identified in the treated leachate. During the process, the by-products NButylbenzenesulfonamide and N-[2-(4-Methylphenoxy)ethyl]acetamide were formed. Ecotoxicological tests using the bioindicator Artemia salina showed a significant reduction on the toxicity after the photo-Fenton process, strengthen the hypothesis of removal of most toxic compounds present in the leachate. The process demonstrated to be efficient, especially in the reduction of the toxic effects of landfill leachate, being able to contribute in minimizing the environmental impacts caused by its discharge in soils or water bodies.