Fabrication of magnetic Cu2O nanocomposites for enhanced iodide removal: Adsorption properties, mechanism and application

The presence of iodine in water poses significant health risks to humans and aquatic ecosystems, necessitating the development of efficient and sustainable remediation strategies. Here, we present Fe3O4/Ti3C2Tx/Cu2O-Cu nanocomposites as high-performance adsorbents for iodide removal. A multistep process was utilized in the fabrication of the nanocomposite, which involved the modification of Fe3O4 nanoparticles with polydopamine (PDA) and the assembly of Ti3C2Tx nanosheets, followed by the growth of Cu2O/Cu nanoparticles. The nano- composites showed a maximum iodide adsorption capacity of 41.34 mg/g at 25 degrees C, following quasi second-order adsorption kinetics and the Langmuir adsorption isotherm. A thermodynamic study revealed that the adsorption process was exothermic and spontaneous. Additionally, the nanocomposite displayed excellent selectivity for iodide despite competing anions and retained over 50 % of its adsorption capacity after two washing cycles. A mechanistic investigation indicated that the removal of iodide was primarily due to the formation of insoluble CuI under acidic conditions and surface complexation between Cu2O and iodide under neutral conditions. Owing to its high adsorption capacity, good selectivity, magnetic separability, and reusability, the Fe3O4/Ti3C2Tx/Cu2O- Cu nanocomposite offers great promise for the effective remediation of iodide-contaminated water. This study provides valuable insights into the development and application of advanced functional materials for addressing the critical issue of water pollution due to iodine.