The current study aims to use Allium scorodoprasum L. biomass as an adsorbent for the bioremoval of Remazol black 5 (RB5) dye from aqueous solutions. The binding capacity of Allium scorodoprasum L. biosorbent to RB5 was investigated by recording the changes in pH, concentration of RB5 dye, temperature and contact time in batch aqueous solutions. Dubinin-Radushkevich (D-R), Freundlich, and Langmuir isotherm models were used to explain the experimental data. The maximum RB5 dye biosorption capacity of the biosorbent was found to be 19.8 mg g-1 at 25 oC. The average biosorption-free energy indicated that the biosorption event took place by chemical reaction and that it followed the PFO and IPD rate kinetics, respectively. Finally, thermodynamic adsorption studies indicated that the RB5 dye biosorption was both endothermic and spontaneous. The Allium scorodoprasum L. had a significant adsorption capacity for the anionic RB5 dye.
