فهرست نشریات علمی دسترسی آزاد ایران

The increasing contamination of water bodies by heavy metals, particularly lead (Pb (II)), poses a significant threat to environmental and public health. This research investigates the synthesis, characterization, and Pb (II) adsorption capabilities of a novel sodium alginate-g-poly (acrylic acid-co-Itaconic acid)/ titanium dioxide [SA-g-p(AA-IA)/ TiO₂] hydrogel nanocomposite. The nanocomposite was synthesized via free-radical polymerization and characterized using FTIR, XRD, and FESEM, which confirmed successful grafting, the incorporation of TiO₂ nanoparticles, and a porous structure. The influence of various operational parameters, including time, pH, temperature, and Pb (II) dose, on adsorption was systematically evaluated. The nanocomposite demonstrated a substantial Pb (II) adsorption capacity, reaching approximately 998.62 mg/g at pH 10, with equilibrium attained within 90 minutes. Kinetic analysis indicated that adsorption followed a pseudo-second model, suggesting chemisorption as primary mechanism. Adsorption isotherm data fitted to Freundlich and Temkin models, showing multilayer adsorption. Thermodynamic analysis revealed the process to be spontaneous (ΔG = -5.439 kJ/mol) and endothermic (ΔH = 23.404 kJ/mol). The hydrogel composite also exhibited pH-sensitive swelling behavior, with maximum swelling observed under alkaline conditions. These results highlight potential of SA-g-p(AA-IA)/TiO₂ nanocomposite as an effective adsorbent for Pb (II) removal from solutions.