Preparation of novel Acrylamide/gum Arabic/carbon nanotube hydrogel nanocomposite and its application for removal of cationic pollutants

The discharge of dye-containing industrial effluents into aquatic environments poses ecological risks due to the toxicity of synthetic dyes such as methylene blue (MB). Developing stable and reusable adsorbents remains a critical challenge in wastewater treatment. In this work, a reinforced Acrylamide/gum Arabic/carbon nanotube nanocomposite was synthesized via free-radical polymerization and evaluated for MB removal from aqueous solutions. The prepared nanocomposite was characterized by FTIR, FE-SEM and TGA, confirming effective crosslinking and homogeneous nanofiller dispersion. Adsorption experiments were conducted to examine the influence of pH, initial dye concentration, adsorbent dosage, and contact time. In optimized conditions (15 mg L−1 MB, pH = 7, 0.05 g adsorbent, 60 min at room temperature), a maximum removal efficiency of 80% was achieved. Equilibrium data were best fitted to the Freundlich isotherm, while kinetic analysis followed the pseudo-second-order, indicating heterogeneous multilayer adsorption governed predominantly by chemisorption. Thermodynamic parameters revealed that the process is spontaneous and exothermic.