TITLE:
Chemical Degradation of Indigo Potassium Tetrasulfonate Dye by Advanced Oxidation Processes
AUTHORS:
Veronica Camargo, Elba Ortiz, Hugo Solis, Carlos M. Cortes-Romero, Sandra Loera-Serna, Carlos J. Perez
KEYWORDS:
Indigo Potassium Tetrasulfonate, Advanced Oxidation Processes, Chemical Degradation, Theoretical Calculations
JOURNAL NAME:
Journal of Environmental Protection,
Vol.5 No.13,
October
30,
2014
ABSTRACT: The experimental degradation of a water soluble dye, potassium indigo tetrasulfonate salt, has been studied using stand-alone
ozonation and photocatalytic oxidation process. Progress of the dye oxidation
was followed by UV-VIS spectrophotometric measurements at controlled operating
conditions. The organic content of reaction samples was measured to verify the
process efficiency in dye mineralization. According to current results, almost
complete color removal was obtained for ozonation within about 1 h reaction
time. The reduction of the organic load was almost 80% from its original while
initial sulphur content decreased to 32.5%. Dye conversion of 100% was obtained
by means of a photocatalytic process using TiO2 as catalyst at 294
nm irradiated UV light. This complete color removal for the catalytic process
was observed within 7 min of reaction time. The calculated initial rate of
reaction of photocatalysis treatment was 8 times faster than that of
ozonolysis. However, the remaining organic load of photocatalysis was almost
88% from its original while the final sulphur content was 27.3%. This
contrasting behavior of the performance of the type of oxidation process
stressed importance of physicochemical phenomena and intermediates molecules
present during dye degradation. An insightful and mechanistic aspect of the dye
oxidation was developed by performing quantumchemical calculations.