Facile synthesis of Al₂O₃/Sodium dodecyl sulphate/2-aminophenol composite for efficient removal of Pb(II), Cd(II), and Co(II) ions from aqueous media

In this paper, Al₂O₃ nanoparticles with an average crystallite size of 35.56 nm are facilely synthesised using the combustion procedure in the presence of glutamine as organic fuel. Besides, Al₂O₃/Sodium dodecyl sulphate/2-aminophenol composite is synthesised and applied as a novel adsorbent for the removal of Pb(II), Cd(II), and Co(II) ions from aqueous media. The synthesised samples are characterised using several tools such as X-ray diffraction (XRD), elemental analysis, Fourier-transform infrared spectroscopy (FT-IR), and field emission scanning electron microscopy (FE-SEM). In the case of Al₂O₃, the XRD peaks, which were appeared at 2θ of 38.11, 46.21, and 66.72°, are attributed to the (311), (400), and (440) planes of γ-Al₂O₃, respectively. In the case of Al₂O₃/Sodium dodecyl sulphate/2-aminophenol composite, the existence of a wide XRD peak at 2Ɵ = 25° confirming that the crystal assembly of Al₂O₃ combined or interfered over amorphous organic surroundings. Elemental analysis of the Al₂O₃/Sodium dodecyl sulphate/2-aminophenol composite displayed that the % C, % H, and % N are 17.23, 4.21, and 1.58%, respectively. The maximum adsorption capacity, which was obtained from Langmuir isotherm, of the composite towards Pb(II), Cd(II), and Co(II) ions is 119.19, 101.21, and 86.51 mg/g, respectively. The best description for the experimental results is given by the pseudo-second-order kinetic model and Langmuir adsorption isotherm. Also, the thermodynamic parameters confirmed that the removal of studied ions is spontaneous, exothermic, and chemical. After three adsorption-desorption cycles, 25%V/V (Methanol/HNO₃) is the suitable desorbing medium needed for the recapture of the adsorbed metal ions on the composite. Hence, the synthesised composite could be reutilised without notable losses of its effectiveness.