Degradation de colorants azoïques par les procédés d’oxydation avancée en solution aqueuse.

Abstract

Textile industries release large quantities of wastewater containing dyes with a high toxicity risk. Primary treatment methods are unsatisfactory, advanced oxidation processes (AOPs) are effective. They allow the total mineralization of pollutants in CO2, H2O and corresponding mineral acids. The photochemical process during the degradation of OG has been studied. Photocatalysis in the presence of NIO is more effective than TiO2, 91% and 85% of OG disappeared after 300 minutes respectively. A parametric study was performed by UV-Vis spectrophotometer. The results of photochemistry have shown that the NIO-Oxalic Acid -UV process is effective for the degradation of OG. In the second study, we chose a silica-based material of SBA-16 type associated with NIO to degrade OG by catalytic ozonation. The NIO and SBA-16 associated with ozone greatly improve the degradation of OG. The total degradation of the substrate was obtained in half the time with NIO or SBA-16 alone. The primary analytical study of ozonation was confirmed by LC-MS-TOF and led to hydroxyl by-products mainly on aromatic rings. The formation of tertiary by-products such as: phthalic acid, catechol and hydroquinone have been observed. The results of the parameter interactions were obtained through three factorial designs of experiments using NIO, SBA-16 alone and 1: 1 weight /weight of NIO/SBA-16.