Prediction of Breakthrough Curves for Sorptive Removal of Phenol by Bagasse Fly Ash Packed Bed

Sorptive removal of phenol from synthetic aqueous solutions by bagasse fly ash (BFA) was investigated at 303 K under dynamic conditions in a packed bed. The effects of sorbent bed length (Z = 40-90 cm), flow rate (Q = 0.01-0.04 dm(3)/min), bed diameter (D = 2-4 cm), and initial concentration (C-0 = 50-500 mg/dm(3)) on the sorption characteristics of phenol were investigated at an influent pH of 6.5. More than 99.5% of phenol was removed in the column operated at C-0 =100 mg/dm(3) of phenol. The column performance improved with increasing Z and decreasing Q. The Bohart-Adams, Thomas, Yoon-Nelson, Clark, and Wolborska models were applied to the experimental data to represent the breakthrough curves and determine the characteristic design parameters of the column. The bed depth service time (BDST) model at 50% breakthrough provided a good fit to the experimental data, and the sorption capacity of the adsorbent was close to the value predicted from a batch study. The sorption performance of the BFA columns could be well described by the Thomas, Yoon-Nelson, and Clark models at effluent-to-influent concentration ratios (C/CO) higher than 0.08 and lower than 0.99. Application of the Wolborska model to the experimental data for C/C-0 <0.5 enabled the determination of the kinetic coefficients for mass transfer in these systems. All of the models can be applied to describe the dynamic behavior of the column sorption with respect to bed length and flow rates. The sorptive capacity of BFA for phenol was found to be 9.93 mg/g.