Decolorization and mineralization efficiency of the hetero-functional reactive dyes using advanced oxidation processes

• Published in: Desalination and water treatment 2021-07, Vol.227, p.350-359
• Main Authors: Siddiqua, Umme Habibah, Ali, Shaukat, Jabeen, Sobia, Noor, Sadia, Tabassum, Asma, Masood, Nasir, Iqbal, Munawar, Nazir, Arif
• Format: Article
• Language: English
• Subjects: Decolorization; Fenton; Mineralization; Photo-Fenton; Reactive dyes
• ISSN: 1944-3986; 1944-3986
• DOI: 10.5004/dwt.2021.27247

The current study was aimed at the decolorization and mineralization of six newly synthesized hetero-functional (vinyl sulfone and cyanuric chloride) azo reactive dyes (D-1 to D-6) using two advanced oxidation processes (Fenton and photo-Fenton). Results showed that both oxidation mechanisms effectively mineralized the synthesized hetero-functional azo reactive dyes. However, decolorization and mineralization of dyes through photo-Fenton oxidation were more effective than Fenton oxidation. The data revealed that process parameters (pH, Fe2+ dosage, concentration of H2O2, and reaction time) greatly affect the mineralization of the selected dyes. Decolorization efficiency (98%) and chemical oxygen demand (COD) removal (78%) was obtained for the six degraded azo reactive dyes under optimum conditions; pH (3), Fe2+ concentration (20 mg/L), H2O2 (500 mg/L), and contact time (80 min) using Fenton oxidation. On the other hand, 99% decolorization and 82% COD removal was achieved for the photo-Fenton oxidation process under optimum conditions of pH (3), Fe2+ (15 mg/L), H2O2 (300 mg/L), and irradiation time (60 min) for the six hetero-functional azo reactive dyes. From the above results, it was concluded, that both oxidation processes can be effectively employed for the degradation of the six hetero-functional azo reactive dyes.