Remarkable adsorptive capacity and reusability performance of magnetic magnetite@silica@L-histidine nanocomposite towards gaseous benzene pollutant

Herein, magnetic magnetite@silica@L-histidine (Fe₃O₄@SiO₂@L-Hist) core-shell nanoparticles (NPs) were prepared as novel adsorbents via chemical co-precipitation and sol-gel technology for the adsorption of gaseous benzene pollutant. The Fe₃O₄, Fe₃O₄@SiO₂ and Fe₃O₄@SiO₂@L-Hist NPs were characterized using a combination of scanning electron microscopy (SEM), SEM - energy dispersive X-ray (SEM-EDX), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), vibrating sample magnetometry (VSM), Brunauer-Emmett-Teller analysis (BET), X-ray photoelectron spectroscopy (XPS) and thermal gravimetric analysis (TGA). The adsorption capacities of Fe₃O₄, Fe₃O₄@SiO₂ and Fe₃O₄@SiO₂@L-Hist NPs for benzene were found to be 188, 279 and 481 mg g⁻¹, respectively, with Fe₃O₄@SiO₂@L-Hist NPs demonstrating the highest capacity. Kinetic and isotherm studies indicated that the pseudo-2nd-order kinetic model and the Langmuir isotherm model provided the best fit to the experimental data, suggesting favorable physical adsorption. In addition, Fe₃O₄, Fe₃O₄@SiO₂ and Fe₃O₄@SiO₂@L-Hist NPs exhibited remarkable reusability, with reuse efficiencies of 85.67, 89.65 and 91.73 %, respectively, after five recycle cycles, demonstrating their potential for practical benzene remediation applications. Overall, this study offers valuable insights into creating effective and sustainable adsorbents for eliminating volatile organic compounds (VOCs). This contributes to mitigating air pollution and safeguarding both human health and the environment.