فهرست نشریات علمی دسترسی آزاد ایران

Hydrogels were synthesized via free-radical polymerization using sodium-g-poly(acrylamide-crotonic acid) alginate, with reactant concentrations optimized using the Taguchi method. Furthermore, a nano-hydrogel was prepared by adding silica nanoparticles. The hydrogel and nanocomposite were characterized using FTIR, FESEM-EDX, TEM, XRD, TGA, and BET-BJH spectroscopy. The study focused on the removal of lead (Pb²⁺) ions from aqueous solutions. The maximum adsorption capacity was 243.667 mg/g at 35 °C, and the adsorption kinetics were found to be consistent with a pseudo-second-order reaction model. Moreover, the adsorption of lead (Pb²⁺) ions followed Freundlich and Temkin isothermic patterns. The Pb²⁺ removal study at different temperatures (5, 15, 25, and 35 °C) demonstrated that the adsorption process is primarily a physical one. Gibbs free energy, enthalpy, entropy, and equilibrium constant were calculated. In this study, we investigated the effects of both temperature and pH. The results showed that with increasing pH and temperature, adsorption efficiency increased, consistent with the endothermic nature of the process, which was spontaneous. The Pb²⁺ removal efficiency was verified after washing the adsorbent with sodium hydroxide, and the results were very encouraging, even after five washes.