Removal of methylene blue from aqueous solutions by straw based adsorbent in a fixed-bed column

In this paper, carboxymethyl straw has been applied to eliminate methylene blue (MB) in a fixed-bed column. The straw based adsorbent has shown high MB uptake in column. Various models such as Thomas, Clark, Adams–Bohart, Yoon–Nelson, Wolborska, and BDST model have been employed to fit the experimental data carefully. Among them, Thomas model is found to be the most suitable one to describe the adsorption behaviors, according with the monolayer chemical adsorption mechanism. Then the effects of initial solution pH, bed height, temperature, initial MB concentration and flow rate on column adsorption have been studied in detail based on Thomas model. It has been found that initial solution pH, bed height, initial MB concentration and flow rate can affect the breakthrough curves obviously, while temperature has no evident influence on the MB adsorption of the modified straw.

► Applications of carboxymethyl straw adsorbent in the removal of methylene blue in a fixed-bed column.
► Investigation of the effects of various factors on the column adsorption.
► Study on the adsorption mechanisms by various theoretic models.
► The adsorption behaviors obeying the monolayer chemical adsorption mechanisms.