Evaluating SiO2/Al2O3/poly(acrylic acid-co-glycidyl methacrylate) composite as a novel adsorbent for cobalt(II) radionuclides.

A novel SiO₂/Al₂O₃/poly(acrylic acid-co-glycidyl methacrylate), SiO₂/Al₂O₃/P(AA-co-GMA), composite was synthesized and evaluated for its effectiveness in adsorbing Co(II) ions from aqueous solutions. The composite was analyzed using various techniques including FTIR, SEM, TGA, DTA, and XRD. The composite displays a high specific surface area of 17.451 m²/g, exceeding that of the corresponding copolymer, which measures 0.236 m²/g. Batch adsorption experiments were conducted to investigate the factors influencing the adsorption capacity of the composite for Co(II) ions. In the pH experiments, it was found that at a solution pH of 3.4, the P(AA-co-GMA) copolymer alone showed limited capability in adsorbing Co(II) ions, achieving only 3.82 mg/g. However, upon integration of SiO₂/Al₂O₃ into the polymer matrix, the composite exhibited a significantly enhanced adsorption capacity of 103.54 mg/g. The adsorption process followed a pseudo-second-order kinetic model and attained equilibrium within 60 min. The Langmuir isotherm model was found to best describe the adsorption behavior, with a maximum adsorption capacity of 217.86 mg/g. The adsorption of Co(II) was significantly affected by the ionic strength, especially with Al³⁺ displaying a more pronounced impact on the adsorption of Co(II) ions compared to Na⁺, Ca²⁺, and Mg²⁺. Thermodynamic studies indicate that the adsorption process was spontaneous and endothermic. Overall, the SiO₂/Al₂O₃/P(AA-co-GMA) composite material displayed significant adsorption ability for Co(II) ions, making it a suitable option for further development as an effective adsorbent in water treatment applications. [ABSTRACT FROM AUTHOR]