Kinetics of the Photocatalytic Decolorization of an Azo Reactive Dye in Aqueous ZnO Suspensions

• Published in: Industrial & engineering chemistry research Vol. 43; no. 19; pp. 6035 - 6039
• Main Authors: Yatmaz, H. C, Akyol, A, Bayramoglu, M
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 15-09-2004
• Subjects: Applied sciences; Catalysis; Catalytic reactions; Chemical engineering; Chemistry; Exact sciences and technology; General and physical chemistry; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Discoloration; Kinetics; Photocatalysis; Reactive dye
• ISSN: 0888-5885; 1520-5045
• DOI: 10.1021/ie049921z

The photocatalytic decolorization of Remazol Red RR, a commercial azo reactive textile dye, in ZnO suspension, has been investigated in a quartz batch reactor with the use of artificial light source (UV−C). The reaction kinetics are modeled by pseudo-first-order rate law. Regression analysis related pseudo-first-order rate constant, k, to the catalyst loading, empirically as k ∝ [ZnO]0.6. The decolorization rate increases with increasing pH, attaining maximum value at pH 10. The rate constant is inversely related to the initial dye concentration, empirically according to the relation k ∝ [C0]-1.5. Finally, the rate constant is found proportional to the square root of the light intensity as k ∝ [I] 0.5. These empirical models are therefore combined as k ∝ [ZnO]0.6 [C0]-1.5 [I]0.5