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), N₂ adsorption-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⁺.