Synthesis of Organic–Inorganic Hybrid Magnetic Material for Removal of Co(II), Ni(II) and Cu(II) Ions from its Aqueous Solutions

From biomass residues, organic-inorganic hybrid polymeric compounds have been synthesized with a high ability to adsorb metal ions Co(II), Ni(II), and Cu(II) from their aqueous solutions. The method can be summarized: after preparing sodium silicate using rice husks by digestion with sodium hydroxide base, the freshly prepared Fe₃O₄ magnetic nanoparticles were introduced. By treating the mixture with nitric acid, 3-aminopropyltriethoxysilane, and 2-amino-3,5-dibromobenzaldehyde, the polymer labeled Fe₃O₄@RH-SiO₂ADB was prepared. X-ray technique revealed the prepared materials to be crystalline. Based on N₂-(adsorption-desorption) analysis, Fe₃O₄@RH-SiO₂PrNH₂ and Fe₃O₄@RH-SiO₂PrADB had specific surface areas of 0.593 m²g^− 1 and 3.576 m²g^− 1, respectively. According to vibrating sample magnetometry (VSM), iron oxide Fe₃O₄ displays ferromagnetic properties, with a saturation magnetization of up to 13.39 emu g^− 1, while the Fe₃O₄@RH-SiO₂PrNH₂ and Fe₃O₄@RH-SiO₂PrADB materials’, clearly demonstrated a loss of magnetism up to 3.88 and 3.87 emu g^− 1, respectively. Under a set of conditions such as vibration time, pH effect, metal concentration, and solid mass of polymer Fe₃O₄@RH-SiO₂PrADB, the metal ions Co(II), Ni(II), and Cu(II) were adsorbed from their aqueous solutions. Under ideal circumstances, the sorption capacity was 1666.67 mg/g for Ni (II) and 5000 mg/g for Ni (II) and Cu (II).