Comparison of fixed-bed properties of walnut shell and coconut shellbased activated carbons for dynamic adsorption of methylene blue

In this study, dynamic adsorption of methylene blue (MB) on two types of activated carbons (AC), produced from walnut shell and coconut sell was investigated using a lab-scale fixed-bed adsorption column. Effects of three fundamental parameters in dynamic adsorption process i.e., initial feed concentration, flow rate and active bed length were studied in the light of the breakthrough curve analysis. MB removal percentage and bed adsorption capacity of the two types of ACs were calculated and compared to evaluate the column adsorption performance of the adsorbents. The average values of MB removal percentage for coconut shell and walnut shell-based ACs were obtained as 42.08% and 41.78%, respectively. The results were comparable; however, a little better for the coconut shell-based AC due to its higher surface area in comparison with the walnut shell-based AC. On the other hand, walnut shell-based AC exhibited superior bed adsorption capacity (0.686 mg/g) compared to that of the coconut shell-based AC (0.534 mg/g), owing to its lower density and larger pore size.

Comparison of fixed-bed properties of walnut shell and coconut shellbased activated carbons for dynamic adsorption of methylene blue Keywords:

Activated carbon , coconut shell , walnut shell , fixed-bed column , methylene blue