Homogeneous catalytic ozonation of C.I. Reactive Red 2 by metallic ions in a bubble column reactor

• Published in: Journal of hazardous materials Vol. 154; no. 1; pp. 748 - 755
• Main Authors: Wu, Chung-Hsin, Kuo, Chao-Yin, Chang, Chung-Liang
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 15.06.2008; Elsevier
• Subjects: Applied sciences; Catalysis; Catalytic ozonation; Catalytic reactions; Chemical engineering; Chemistry; Co(II); Color; Coloring Agents - chemistry; Exact sciences and technology; Fe(II); Fe(III); General and physical chemistry; Hydrogen-Ion Concentration; Metals, Heavy - chemistry; Mn(II); Naphthalenesulfonates - chemistry; Ni(II); O 3; Oxidants, Photochemical - chemistry; Ozone - chemistry; Pollution; Reactors; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Triazines - chemistry; Waste Disposal, Fluid - methods; Water Pollutants, Chemical - chemistry; Water Purification - methods; Zn(II); Zn(II); O 3; Mn(II); Fe(II); Ni(II); Co(II); Fe(III); Catalytic ozonation; Discoloration; Catalytic reaction; Iron II; Radical scavenger; Operating conditions; Ozonization; Iron III; Ο3; Bubble column; Reactive dye; pH; Physicochemical purification; Reactor; Catalyst
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2007.10.087

This study elucidates the decolorization of C.I. Reactive Red 2 (RR2) by homogeneous catalytic ozonation. The effects of pH and catalyst dosage were evaluated in O 3/Mn(II), O 3/Fe(II), O 3/Fe(III), O 3/Zn(II), O 3/Co(II) and O 3/Ni(II) systems. In O 3/Mn(II), O 3/Fe(II) and O 3/Fe(III) systems, increasing the catalyst concentration increased the rate of RR2 decolorization; however, further increasing the catalyst concentration caused no further significant increase. When 0.6 mM catalyst was added, the decolorization rates of O 3/Mn(II), O 3/Fe(II), O 3/Fe(III), O 3/Zn(II), O 3/Co(II) and O 3/Ni(II) systems at pH 2 were 3.295, 1.299, 1.278, 1.015, 0.843 and 0.822 min −1, respectively. Under all of the experimental conditions, the decolorization efficiency of catalytic ozonation exceeded that of ozonation alone. The decolorization rate markedly exceeds the TOC removal rate in all tested systems. The effect of the radical scavenger on the catalytic ozonation processes suggests that the decolorization reaction in catalytic ozonation systems proceeds by mainly radical-type mechanisms, except in the O 3/Mn(II) system.