Removal of eosin Y and eosin B dyes from polluted water through biosorption using Saccharomyces cerevisiae: Isotherm, kinetic and thermodynamic studies

Biosorption of two anionic dyes, eosin Y and eosin B, from aqueous solution using Saccharomyces cerevisiae was investigated in a batch mode. The influence process parameters such as contact time, initial dye concentration, sorbent dosage, pH and temperature of aqueous solution were studied. The maximum adsorption capacities were found to be at 200 and 100 mg g-1 for eosin Y and 1 eosin B, respectively. The Langmuir and Temkin model were found to be appropriate for the description of biosorption process of eosin Y and eosin B, respectively. The pseudo-second order kinetic model fitted well in correlation to the experimental results for both dyes. Thermodynamic parameters such as enthalpy change (ΔH°), entropy change (ΔS°) and free energy change (ΔG°) were also investigated. Thermodynamic studies indicated that biosorption of both dyes onto S. cerevisiae was an endothermic process. The negative values of free energy change showed that the biosorption of both dyes was spontaneous at the temperatures under investigation. These results indicate that biomass S. cerevisiae particles with clean surface and high porosity are an interesting alternative for dye removal from the wastewater effluents.