Excellent adsorptive performance of novel magnetic nano-adsorbent functionalized with 8-hydroxyquinoline-5-sulfonic acid for the removal of volatile organic compounds (BTX) vapors

In this study, magnetic Fe₃O₄/AC@SiO₂ nanoparticles functionalized with 8-hydroxyquinoline-5-sulfonic acid (Fe₃O₄/AC@SiO₂@8HQ5SA) were innovatively prepared, characterized, and applied as a novel nano-adsorbent to efficiently remove volatile organic compounds, namely benzene, toluene, and xylene (BTX) vapors. Fe₃O₄/AC@SiO₂@8HQ5SA was synthesized via the co-precipitation and sol–gel methods. The characterization of Fe₃O₄/AC@SiO₂@8HQ5SA as a proposed nano-adsorbent was performed by various spectroscopic methods including FTIR, SEM, TGA/DTA, BET, VSM, XPS, and EDS. The operating factors namely retention time, inlet BTX concentration and temperature were substantially analyzed and optimized to achieve the maximum adsorption capacity of Fe₃O₄/AC@SiO₂@8HQ5SA towards the uptake of the BTX vapors. The adsorption phenomena of Fe₃O₄/AC@SiO₂@8HQ5SA towards the BTX vapors were clarified by the investigation of the kinetic and isotherm criteria. According to the results of the adsorption experiments Fe₃O₄/AC@SiO₂@8HQ5SA demonstrated an admirable performance for the removal of the BTX vapors. The maximum adsorption capacities of the BTX vapors by Fe₃O₄/AC@SiO₂@8HQ5SA were determined as 555.85, 620.80 and 745.54 mg/g, respectively. In addition to the distinctive adsorptive behavior in removing the BTX vapors, the reusability experiments with five adsorption–desorption cycles indicated that Fe₃O₄/AC@SiO₂@8HQ5SA showed excellent reusability. After five consecutive adsorption–desorption cycle tests, Fe₃O₄/AC@SiO₂@8HQ5SA maintained the reuse efficiencies of 91.92%, 91.17% and 90.65% for the BTX vapors, respectively. The findings of this study suggested that the functionalization of the Fe₃O₄/AC@SiO₂ nanoparticles with 8HQ5SA was an effective strategy to greatly increase the removal capacity of BTX vapors, and that the magnetic Fe₃O₄/AC@SiO₂@8HQ5SA was a promising and regenerable nano-adsorbent for the efficient treatment of volatile organic compound pollutants.