Application of RR 4 biosorption models

Protonated beer waste was used as a new type of adsorbent for the removal of Reactive Red 4 (RR 4). Various experimental parameters were investigated. Adsorption reached equilibrium in 18 hours. As the solution pH decreased the dye uptake increased, and under alkaline conditions desorption was dominating. The pseudo-second-order model and Langmuir isotherm model provided a high degree of correlation with the experimental data for the biosorption processes. The rate constant, the equilibrium sorption capacity and the initial sorption rate were calculated. The maximum adsorption capacities of beer waste were 82.23±8.67 and 72.50±6.45 mg/g at pHs 1 and 2, respectively. Kinetic study showed a pseudo-second-order rate of adsorption with respect to the solution. These results of adsorption performance indicate the beer waste as a potentially economical adsorbent for dye removal.