Efficient Removal of Anionic and Cationic Dyes from an Aqueous Solution Using Pullulan-graft-Polyacrylamide Porous Hydrogel

A pullulan-graft-polyacrylamide porous hydrogel was prepared by radical polymerization in the presence of a crosslinking agent (N,N'-methylenebisacrylamide). Then, the swelling behavior of the hydrogel and the kinetics of swelling were investigated. The novel synthesized hydrogel was used as an adsorbent for removal of dyes from aqueous solutions. In this study, methylene blue (MB) and reactive blue 2 (RB) were selected as representative cationic and anionic dyes, respectively. The synthesized porous hydrogel exhibited excellent adsorption ability for both dyes. Various experimental conditions affecting the dye adsorption were explored to achieve maximum removal of both dye molecules. In addition, kinetic, thermodynamic, and adsorption isotherm models were employed to describe the dye adsorption process. The results indicated that the prepared hydrogel is an efficient adsorbent for dyes and possesses the ability to be regenerated without losing its original activity and stability for water treatment applications.