Facile crosslinking synthesis of hyperbranch-substrate nanonetwork magnetite nanocomposite for the fast and highly efficient removal of lead ions and anionic dyes from aqueous solutions

Abstract

The aim of the present work was to investigate the effect of surface functional group density on the adsorption behaviors of functionalized mesoporous Fe₃O₄. Amino modified mesoporous Fe₃O₄ (Fe₃O₄–NH₂) nanoparticles were firstly prepared through a classical solvothermal method, then a novel three-dimensional hyperbranch structured nanocomposite (Fe₃O₄–HBPA) was synthesized though amino terminated hyperbranched polymer (HBPA) modification without any toxic cross-linking agent. The resulting functionalized mesoporous Fe₃O₄ composites were characterized by means of TEM, SEM, FTIR, XRD, VSM, TGA and zeta potential. Adsorptive removal of Pb²⁺ and MO in their respective single-component and binary systems was studied. For heavy metal ions (Pb²⁺, Hg²⁺, Cd²⁺, Cu²⁺ etc.) and dyes (MO, MGO, MBH, RB and CV), Fe₃O₄–HBPA showed higher removal efficiency of Pb²⁺ and MO than Fe₃O₄–NH₂. The adsorption of Pb²⁺ and MO on Fe₃O₄–HBPA was pH dependent with uptake dropping in acidic solution. The Fe₃O₄–HBPA adsorbent showed a quick adsorption rate, high adsorption capacity, and high selectivity for cationic adsorbates. The maximum adsorption capacity was as high as 285.714 mg g⁻¹ for Pb²⁺ and 146.565 mg g⁻¹ for MO. The suitability of the Langmuir adsorption model and pseudo second-order kinetics for describing the adsorption isotherms and kinetics of Fe₃O₄–HBPA for Pb²⁺ and MO dye was examined, respectively.