Abstract
A new method for disperse dye decolourization using the photochemically active silicadodecatungstic acid (H4SiW12O40) + isopropanol (electron donor) redox system has been described. Results of a series of control experiments have indicated that the one-electron reduced form of the silicadodecatungstic acid, SiW12O5-40, was responsible for reductive cleavage of disperse dye as evidenced by photochemical heteropoly blue generation upon H4SiW12O40 + isopropanol UV-illumination. A threshold (0.09 mM) and an optimum (0.5 mM) heteropoly acid dose existed for minimum and maximum decolourization rates, respectively. It was also evident that decolourization kinetics were first-order with respect to dye concentration for concentrations up to 75 mg/l, and the photochemical degradation rate became UV-light penetration limited (zero order) above 100 mg/l dye concentration.
Original language | English |
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Pages (from-to) | 167-176 |
Number of pages | 10 |
Journal | Dyes and Pigments |
Volume | 60 |
Issue number | 2 |
DOIs | |
Publication status | Published - Feb 2004 |
Keywords
- Decolourization
- Disperse dyes
- H SiWO
- Heteropoly acid
- Heteropoly blue
- Photochemical degradation