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

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 threedimensional 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.