Removal of methylene blue from water using eggshell membrane fixed bed

Abstract

The purpose of this work was to remove methylene blue (MB) from water using natural eggshell membrane (ESM) in fixed-bed column. The ESM was treated and characterized by Fourier transform infrared spectra (FTIR), scanning electron microscope (SEM) and X-ray diffraction (XRD). A series of experiments were carried out to investigate the effects of bed height on breakthrough curve, flow rate, MB concentration, solution pH (2–10), the ionic strength and temperature on the adsorption behavior. The experimental results show that the adsorption capacity increases with the increase in the bed depth and MB concentration. However, it decreases with increasing the flow rate and temperature. The ESM adsorption capacity of MB is more pronounced in basic medium. The addition of NaCl salt ions decreases the fixation of MB on ESM. Five kinetic models, Bohart–Adams, Wolborska, Thomas, Yoon–Nelson and bed depth service time (BDST) models were applied to experimental data in order to predict the breakthrough curves using non-linear regression and to determine the characteristic parameters of the column useful for process design. The results showed that Thomas and Yoon–Nelson models were found suitable for the normal description of breakthrough curve at the experimental condition, while Adams–Bohart and Wolborska models were only for an initial part of dynamic behavior of the ESM column. Desorption of MB from ESM bed was performed with distilled water as the desorbing agent, and reuse study was investigated.