Advanced superparamagnetic cross‐linked chitosan‐based biosorbent hydrogel for efficient removal of indigo carmine dye from water: Adsorption isotherms, kinetics, and thermodynamic studies

Water contamination from industrial dyes poses a significant threat to the environment and human health. This study focuses on the development of advanced porous cross‐linked chitosan‐based hydrogels and superparamagnetic hydrogel nanocomposites for efficient removal of indigo carmine (IC) dye from water. The hydrogels were cross‐linked using benzophenonetetracarboxylic dianhydride (BTDA) and incorporated functionalized magnetic iron nanoparticles (CP‐MNPs). A comparative study revealed that the superparamagnetic hydrogel nanocomposite exhibited superior performance in IC dye adsorption. Higher IC removal efficiencies were observed at lower amounts of cross‐linker, pH, and adsorbent dosage. The superparamagnetic hydrogel nanocomposite demonstrated superior IC dye adsorption compared with the chitosan hydrogel. The adsorption process followed a pseudo‐second‐order kinetic model and Langmuir isotherm model. Thermodynamic data indicated that the adsorption onto the superparamagnetic hydrogel nanocomposite was endothermic and spontaneous, making it a promising material for environmental applications.