Magnetic carbonaceous adsorbents derived from nanocomposites of hypercrosslinked polystyrenes

Two groups of porous composite adsorbents with magnetic properties were obtained by pyrolysis of nanocomposites of hypercrosslinked polystyrenes with immobilized iron and cobalt oxides. The structure of the adsorbents is characterized by electron microscopy, X-ray phase analysis, Raman spectroscopy, adsorption of N2, CO2. The carbonaceous adsorbents (granules 0.1–0.3 mm) possess magnetic properties and have a developed porous structure (three ultramicropore fractions of 0.3–0.9 nm, a specific surface area of up to 600 m2 g−1). The crystalline phase of the magnetic adsorbents consists of iron, cementite, maghemite (41, 49, 9 wt%), or cobalt, graphite (9, 87 wt%). Iron/cementite nanoparticles 30–200 nm or cobalt nanoparticles 9–40 nm are distributed uniformly in the carbon matrix of the adsorbents. Carbon nanosized layered structures form the shells (2–7 nm). The magnetic adsorbents are capable of absorbing toxic organic compounds up to 0.64 cm3 g−1. The resulting adsorbents can be applied in magnetic separation adsorption technologies. [Display omitted] •Carbonaceous adsorbents in the form of spherical granules were obtained.•Pyrolysis of nanocomposites of hypercrosslinked polystyrenes.•Adsorbents contain nanodispersed cobalt or iron and have magnetic properties.•Magnetic composites have a developed microporous structure.•Composite adsorbents are capable of absorbing toxic organic compounds.