Mitigation of orange II dye from simulated and actual wastewater using bimetallic chitosan particles: Continuous flow fixed-bed reactor

• Simulated and actual textile wastewaters were potently treated in the BCP-bed column.
• The adsorption performance of BCP was highly dependent on operating parameters.
• The data obtained from column study fit BDST model well.
• The adsorption capacity of 19 mg/g was achieved after three recycles of BCP-bed.
• The BCP-bed column had better adsorption performance compare to SAC-bed column.

Continuous fixed-bed column studies were carried out by using bimetallic chitosan particles (BCP) as an adsorbent for the elimination of the anionic dye orange II (OII) from simulated and actual wastewaters. The effects of different parameters including bed heights (3, 5, and 7 cm), influent OII concentrations (50, 100, and 200 mg/L), and flow rates (4, 7, and 10 mL/min) were investigated experimentally, and the corresponding breakthrough curves were calculated. The maximum adsorption capacity of BCP was attained 44 mg/g at 200 mg/L influent concentration of OII, 5 cm bed depth, and flow rate of 7 mL/min. The OII adsorption potential of the BCP was compared by the standard activated carbon (SAC) using a bench scale adsorption column. Breakthrough curves were predicted by applying Thomas, bed depth/service time (BDST), Yoon–Nelson, and Clark models, respectively, and the corresponding model parameters were obtained. The BDST model showed the best compromise with the experimental data. The adsorption capacity of BCP for OII dye removal from the actual wastewater after three cycles of adsorption–desorption was achieved to 19 mg/g in the fixed bed column. It can be concluded that the applied column presents a promising and efficient method for the removal of OII from wastewaters.