Adsorption of Cu(II) on three adsorbents, Fe3O4/Ni/NixB nanocomposite, carob (Ceratonia siliqua), and grape seeds: A comparative study

A novel adsorbent Fe3O4/Ni/NixB nanocomposite was synthesized and used for the adsorption of copper. Moreover, natural adsorbents carob and grape seeds were used for this purpose. The surfaces and the elemental compositions of the adsorbents were characterized by SEM-EDX. The zero point charges of pH of Fe3O4/Ni/NixB nanocomposite, carob, and grape seeds were found as 8.4, 6.0, and 5.6, respectively. The Langmuir, Freundlich, and Dubinin–Radushkevich isotherm models were used for the identification of the mechanism of the adsorption. The adsorptions of Cu(II) on the three adsorbents were well fitted to the Langmuir isotherm.