Synthesis of guar gum-acrylic acid graft copolymers based biodegradable adsorbents for cationic dye removal

Guar gum-poly(acrylic acid-aniline) based interpenetrating network hydrogels were prepared via two-step aqueous polymerization in which aniline monomer was in situ polymerized to induce electrical conductivity. The hydrogels were characterized by FTIR, TGA and SEM techniques. Biodegradation of synthesized hydrogels was performed in soil burial and composting conditions. Synthesized hydrogel was evaluated as an adsorbent to remove cationic dye [methylene blue (MB)] from aqueous solution. The contact time, adsorbent dosage, pH and temperature were optimized for maximum adsorption. The kinetics of MB adsorption was analyzed using the pseudo first order and pseudo second order models. Pseudo second order kinetic model represents better experimental data than the pseudo first order model, which indicates that adsorption system fits into second order kinetics model.