Heavy metal ion adsorption behavior in nitrogen-doped magnetic carbon nanoparticles: Isotherms and kinetic study

► The monodisperse and multigram-scale N-MCNPs are fabricated by carbonization of polypyrrole as a carbon precursor. ► The synthesized N-MCNPs provide an enhanced adsorption uptake for various heavy metal ions. ► The N-MCNPs can be applied to the Langmuir model and pseudo-second-order kinetics. ► The iron-impregnated N-MCNPs are reused up to 5 times with no loss of removal efficiency.