Adsorption Behavior of Basic Dye from Aqueous Solution onto Alkali Extracted Lignin

Alkali extracted lignin (AEL), isolated from corn stalks with dilute alkali solution under mild condition, was used as a low-cost adsorbent for the removal of methylene blue (MB) from aqueous solutions. Batch adsorption studies were conducted to evaluate various experimental parameters such as pH, contact time, and initial dye concentration for the removal of MB. The kinetic data were analyzed using pseudo-first-order and pseudo-second-order kinetic models, and the adsorption kinetics were found to be well represented by the pseudo-second-order kinetic model. The equilibrium data were perfectly fitted to the Langmuir isotherm equation when compared with Freundlich isotherm equation. Based on the Langmuir adsorption isotherm model, the predicted maximum monolayer adsorption capacity was found to be 121.20 mg g-1 (at 30 oC). The results showed that this adsorbent had a high adsorption capacity, making it a promising alternative for dye removal.