Performance, kinetics and equilibrium in biosorption of anionic dye Reactive Black 5 by the waste biomass of Corynebacterium glutamicum as a low-cost biosorbent

The protonated biomass of Corynebacterium glutamicum was used for the removal of Reactive Black 5 (RB 5). In batch experiments, the parameters studied included the effect of the dye concentration, pH, contact time, salt concentration and temperature. In the range of pH 1-3, the removal of RB 5 was kept at near 100%. The maximum uptakes estimated by using the Langmuir model were 169.5 and 185.2 mg/g at 20 and 40 °C, respectively. Kinetic studies showed a pseudo second-order rate of biosorption with respect to the solution. The uptake of RB 5 was not significantly affected by the high concentration of salts. Various thermodynamic parameters such as ΔG°, ΔH°, and ΔS° were evaluated with results indicating that this system was a spontaneous and endothermic process. In addition, the biomass could be repeatedly reused up to five times of sorption/desorption cycle, confirming that the biomass wastes can be a potential regenerable biosorbent for RB 5 removal.