Kinetics and Energetics of Azo Dye Decolorization by Pycnoporus sanguineus

Trypan Blue, an azo dye, was decolorized using the self-immobilizing fungal biomass of Pycnoporus sanguineus. The extent and the rate of dye decolorization were directly proportional to the initial dye concentration (20–60 mg L) and the reaction temperature (25–45°C). Mass transfer within and outside the pellets did not limit dye degradation. The apparent kinetics of the decolorization reaction followed a first-order behavior. Activation energy for the biological decolorization was calculated at 23 kJ mol. The decolorization process was endothermic with the enthalpy and entropy values calculated at 45.6 kJ mol and 146 J mol K, respectively. Based on the value of Gibbs free energy change, the decolorization reaction under the conditions studied was non-spontaneous below 39°C but was spontaneous at higher temperatures.