Application of residual brewery yeast for adsorption removal of Reactive Orange 16 from aqueous solution

• The residual brewery yeast is effective adsorbents for Reactive Orange 16 dye.
• The pH factor is the most important factor on Reactive Orange 16 dye adsorption.
• The residual brewery yeast is an efficient low cost adsorbent for reactive dyes.

The adsorption characteristics of C.I. Reactive Orange 16 (RO 16) from aqueous solution onto residual brewery yeast were investigated under various experimental conditions. At pH 3.0 and 308 K, the adsorption capacity of RO 16 onto residual brewery yeast was found to be 0.56 mol/kg. Experimental data indicated that the adsorption capacity of residual brewery yeast for the dye was higher in acidic, than in neutral or basic solutions. The adsorption equilibrium data showed good correlation with the Langmuir isotherm models. The estimated values for the free energy of adsorption (ΔGo) were −6.661, −4.812 and −3.929 kJ/mol at 288, 298 and 308 K, respectively, which indicated that a spontaneous process had occurred. The negative values of enthalpy (ΔHo) and entropy (ΔSo) indicated the exothermic nature of the adsorption of RO 16 onto residual brewery yeast. Kinetic studies showed that the biosorption of RO 16 onto residual brewery yeast in the system followed pseudo-second order kinetics.

Change of the peak intensities was reaction between RO 16 dye and functional groups of yeast. The functional groups were phosphate, carboxyl, amine and amide groups.Figure optionsDownload as PowerPoint slide