Magnetic metal organic frameworks (MOFs) composite for removal of lead and malachite green in wastewater

Abstract

We designed and synthesized a magnetic metal organic frameworks (MOFs) composite, Cu-MOFs/Fe3O4 as the adsorbent for removal of lead (Pb(II)) and malachite green (MG) in wastewater. This Cu-MOFs/Fe3O4 can be easily prepared by in-situ growth of Cu-MOFs with doping Fe3O4 nanoparticles. The prepared Cu-MOFs/Fe3O4 composite was well characterized by SEM, XRD, and FTIR spectra. The adsorption experiments found that Cu-MOFs/Fe3O4 can serve as adsorbent for removal of Pb(II) and MG simultaneously. The adsorption capacities were found to be 113.67 mg/g for MG and 219.00 mg/g for Pb2+, respectively, which are significantly higher than reported materials. Adsorption isotherm, kinetics and recyclability of Cu-MOFs/Fe3O4 for removal of Pb(II) and MG were then studied. Adsorption of Pb(II) and MG exhibited Freundlich adsorption isotherm model, with the adsorption kinetics of available second-order kinetic. Physical adsorption for MG and chemical adsorption for Pb(II) were confirmed by Dubinin-Radushkevich (D-R) isothermal adsorption model. The adsorption of Pb(II) and MG in real water samples were then studied. The Fe3O4/Cu-MOFs was found to be recyclable for removal of Pb(II) and MG, can be explored as the potential adsorbent for waste water treatment.