Fe₃O₄ Nanoparticles and Carboxymethyl Cellulose: A Green Option for the Removal of Atmospheric Benzene, Toluene, Ethylbenzene, and <i>o</i>‑Xylene (BTEX)

In this work, we investigate the interaction of gaseous benzene, toluene, ethylbenzene, and <i>o</i>-xylene (BTEX) with Fe₃O₄ nanoparticles and demonstrate the potential application of Fe₃O₄ nanoparticles as adsorbents for BTEX. On the basis of X-ray diffraction, transmission electron microscopy, gas chromatography–mass spectrometry, and gas chromatography–flame ionization detection results, using toluene as a model compound, we find that adsorption is of a heterogeneous nature. At relatively high concentrations of toluene (300–2790 ppmv), X-ray photoelectron spectroscopy results indicate an increase in the divalent cations relative to the trivalent cations of Fe₃O₄ nanoparticles, which is possibly triggered by nanoscale effects. Removal efficiency experiments show that Fe₃O₄ nanoparticles (4 g) reduce 100 ppmv of BETX in air by 83 ± 8%, 95 ± 5%, 97 ± 1%, and 98 ± 2%, respectively. Comparable removal efficiencies were observed for recycled Fe₃O₄ nanoparticles. Toluene was also removed from a flow by Fe₃O₄ nanoparticles bound together with carboxymethyl cellulose, without releasing undesired aerosols. Fe₃O₄ nanoparticles (bare and as a composite) show potential as practical and environmental friendly materials for the remediation of BTEX from air