Robust Visible Light-Induced Degradation of Eriochrome Black-T Using a Green Organo-photooxidative Method

In this study, organo-photooxidative material is used to investigate the degradation of Eriochrome Black-T, a potentially hazardous environmental material. Metal-based catalysts are traditionally used to degrade it, resulting in high costs. A variety of organic acids were screened for organo-photooxidative applications against EBT dye. In the developed reactor box, ascorbic acid is a highly efficient photo-oxidative material. It is a green and eco-friendly photooxidative material with low costs. The degradation efficiency rose from 39 to 92% when 100 ppm of dye and 70 ppm of an organo-photooxidative material were used with a contact period of 240 min. The primary intermediate products of the degraded EBT were also identified using GC–MS and HPLC studies. Following GC–MS analysis, the primary products identified at the retention time of 18.11 min were sodium 3-hydroxy-4-imino-7-nitro-3,4-dihydronaphthalene-1-sulfonate (m/z = 310) and 4-amino-7-nitro-3-oxo-3,4-dihydronaphthalene-1-sulfonic acid (m/z = 279). Additionally, various amines were detected, including 7-amino-4-imino-3,4-dihydronaphthalen-1-ol (m/z = 167). For the degraded EBT dye, HPLC investigation revealed a considerable drop in absorbance at 254 nm. The original dye’s primary peak was detected by HPLC investigation at 9.23 min, whereas the degraded dye showed peaks at 2.63 and 4.26 min, showing its conversion into metabolites. The parameters (dye content, dose of photo-oxidative substance, and time) were optimized using the Response Surface Methodology, resulting in an R² value of 0.9232. Moreover, new technologies can be developed using these insights, and these can also aid in the creation of sustainable wastewater treatment systems. Graphical Abstract: (Figure presented.)