Bio-organics isolated from urban bio-refuse for the photodegration of azo-dyes in aqueous solutions

A bio-organic substances (BOS) was isolated from urban bio-refuse undergoing aerobic biodegradation. The isolated BOS was characterized for chemical composition and performance as sensitizers for the photodegradation of azo-dyes in solution. Three commercial sulphonated azo-dyes, i.e., ethylorange (EO), Orange I (OI) and Orange II (OII), were selected as probe molecules. For these molecules high abatement rates (60–100%) were obtained within few hours of irradiation in the presence of BOS, whereas almost no abatement was observed in the absence of BOS. A delay in the color bleaching was observed, in comparison to the dyes degradation; coloured intermediates were identifi ed. Acute toxicity tests showed a low toxicity for the samples at the end of the degradation process.