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(-1)) and the reaction temperature (25-45A degrees 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(-1). The decolorization process was endothermic with the enthalpy and entropy values calculated at 45.6 kJ mol(-1) and 146 J mol(-1) K(-1), respectively. Based on the value of Gibbs free energy change, the decolorization reaction under the conditions studied was non-spontaneous below 39A degrees C but was spontaneous at higher temperatures.