Adsorption of methylene blue by phoenix tree leaf powder in a fixed-bed column: experiments and prediction of breakthrough curves

Abstract

A continuous adsorption study in a fixed-bed column was carried out by using phoenix tree leaf powder as an adsorbent for the removal of methylene blue (MB) from aqueous solution. The effect of flow rate, influent MB concentration and bed depth on the adsorption characteristics of adsorbent was investigated at pH 7.4. Data confirmed that the breakthrough curves were dependent on flow rate, initial concentration of dye and bed depth. Four kinetic models, Thomas, Adams–Bohart, Yoon–Nelson and Clark, were applied to experimental data to predict the breakthrough curves using nonlinear regression and to determine the characteristic parameters of the column that are useful for process design, while a bed-depth service time analysis (BDST) model was used to express the effect of bed depth on breakthrough curves and to predict the time needed for breakthrough at other conditions. The Thomas and Clark models were found suitable for the description of whole breakthrough curve, while the Adams–Bohart model was only used to predict the initial part of the dynamic process. The data were in good agreement with the BDST model. It was concluded that the leaf powder column can be used in wastewater treatment.