Catalytic degradation of indigo dye by aqueous stable C60 aggregates

ENVR 101

Bo Zhang, bo.zhang@ce.gatech.edu, John D. Fortner, Jaesang Lee, Ching-hua Huang, Jaehong Kim, jaehong.kim@ce.gatech.edu , and Joseph B. Hughes, joseph.hughes@ce.gatech.edu. School of Civil and Environmental Engineering, Georgia Institute of Technology, 200 Bobby Dodd Way, Atlanta, GA 30332
The kinetics and mechanisms of (photo)catalytic reactivity of nano-crystalline forms of C60 suspended in water were studied using indigo dye as a model compound. Batch photochemical reactions were carried out with an UV monochromatic light source (350-400nm). The results showed that approximately 50% of indigo degraded within 8 h of UV irradiation when 4 mg/L of nC60 was applied to 26 micro Molar of indigo at room temperature. The degradation might be due to direct oxidation of indigo by photoexcited triplet C60. Alternatively, indigo might have reacted with singlet oxygen and superoxide radical anion that were produced through C60 mediated energy and electron transfer to oxygen. Approximately 10% of indigo degraded in the absence of light suggesting that indigo adsorption to nC60 surface and/or direct electron transfer and subsequent oxidation of indigo might be possible. A study is currently being conducted to elucidate the mechanism of indigo degradation under varying conditions (e.g., presence or absence of light, varying initial nC60 and indigo concentrations and water quality parameters).