ACS Sustainable Chemistry & Engineering | 2019
Biodegradation Products of a Sulfonated Azo Dye in Aerobic Granular Sludge Sequencing Batch Reactors Treating Simulated Textile Wastewater
Abstract
This study focused on the biodegradation of an azo dye (Acid Red 14, AR14) in two anaerobic–aerobic sequencing batch reactors (SBRs) treating synthetic textile wastewater, operated with aerobic granular sludge under different hydrodynamic regimens. The aim was to investigate the fate of the anaerobic AR14 breakdown products (aromatic amines) during the SBRs’ aerobic reaction phase. Specifically, liquid chromatography coupled with electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) was used for structural characterization of AR14 biodegradation metabolites, their molecular formulas being confirmed by accurate mass measurements. Nineteen molecules potentially related to AR14 were detected in the SBRs, and their relative abundances were followed along the aerobic stage of treatment cycles. The two SBRs shared most of the identified compounds but with differences in their metabolite profiles. Biodecolorization through AR14 anaerobic azo bond reduction was confirmed by the identification of the aro...