Kinetics and thermodynamics of reactive red 239 biosorption from waste water

Biosorption of Reactive Red 239 dye by the yeast Saccharomyces cerevisiae has been investigated as a function of medium conditions. For Reactive Red 239, optimum medium conditions were determined as pH 2, 25 °C temperature, 200 ppm initial Reactive Red 239 concentration and 2 g/L biomass concentration. The most efficient temperature was determined as 400C but because of the commercial reasons 250C was selected. At these conditions, the removal of Reactive Red 239 is % 62,8 and Reactive Red 239 uptake was 64,8 mg/g. Ethanol, methanol and heat treatment enhanced the Reactive Red 239 biosorption capacity. The cells at lag phase of growth curve of Saccharomyces cerevisiae have a higher biosorptive capacity for dye ions than that of stationary phase. The early stages of the logarithmic phase of yeast is provided with a higher dye removal. It is seen that dye removal from biosorbent is difficult and efficiency of desorption of dye ions from Reactive Red 239 loaded biosorbent is low. The salt, which is probably found in textile industry waste water, has positive effects on biosorption of Reactive Red 239.Biosorption of Reactive Red 239 dye by Saccharomyces cerevisiae was explained well with Langmuir model and biosorption kinetics of these dye ions follows pseudo-first order rate model. Activation energies for dye ions were determined as 1,31 kcal.mol-1. Biosorption heat for Reactive Red 239 ions were calculated as, 8,89 kcal.mol-1 which indicates that biosorption is endothermic and chemical adsorption and also physical adsorption occurs.Key Words : Biosorption, Saccharomyces cerevisiae, , Reactive Red 239, reactive dye, equilibrium models