At a given time interval (every 1 h), 3 mL of
dye solution was collected for analysis. The concentrations of IC
dye were analyzed using a UV–vis spectrophotometer (Specord
S100, Analytik Jena, Germany) from the changes in absorbance
at 610 nm against the calibration graph constructed from several
standard solutions of IC at various concentrations. The percentage
of degradation was calculated by Eq. (1):