Magnetic Carbon Porous Polymer Prepared from a New Suspended Emulsion for the Absorption of Heavy Metal Ions

In this study, magnetic carbon nanopolymers (Fe3O4/C@PM) were synthesized by suspension polymerization using magnetic carbon nanoparticles as the matrix, 2-thiophene formaldehyde and acrylamide as the monomers, and ethylene glycol dimethacrylate (EGDMA) as the crosslinking agent. The obtained material was characterized using multiple techniques, including scanning electron microscopy (SEM), infrared spectroscopy (FTIR), X-ray diffraction (XRD), N2adsorption–desorption, and thermogravimetric analysis (TGA). The adsorption effects of Zn2+, Cd2+, and Pb2+in the mixed solution were evaluated using magnetic carbon nanoparticles (Fe3O4/C) and Fe3O4/C@PM as adsorbents. The adsorption isotherms, kinetic models, and cyclic regeneration of various metal ions, including Zn2+, Cd2+and Pb2+, were studied. The results showed that the Fe3O4/C@PM maintained a slightly aggregated spherical morphology similar to Fe3O4/C and exhibited excellent adsorption capacity for all of Zn2+, Cd2+, and Pb2+, with maximum adsorption capacities of 343.3, 250.7, and 177.6 mg·g−1, respectively. The adsorption mechanisms were mainly based on the chemical interactions between metal ions and functional groups on the surface of polymers. The kinetic study revealed that the adsorption process followed a pseudo-second-order kinetic model. When Fe3O4/C@PM was reused five times, its adsorption rates for Zn2+, Cd2+, and Pb2+remained above 81%, indicating its great potential for the treatment of wastewater containing Zn2+, Cd2+, and Pb2+.