Facile Synthesis and Characterization of Fe3O4@SiO2 Core-Shell Magnetic Nanocomposite Functionalized With 4-Piperidinecarboxylic Acid for Dynamic Adsorption of Xylene

Abstract

In the present study, a novel Fe3O4@SiO2@4-PCA core-shell magnetic nanocomposite (NC) was synthesized, characterized and evaluated for its potential in the removal of xylene in the gas phase, a volatile organic compound (VOC). Comprehensive characterization techniques including SEM, EDX, FTIR, XRD, BET, TGA and VSM were employed to analyze the structural and functional properties of Fe3O4, Fe3O4@SiO2, and Fe3O4@- SiO2@4-PCA NCs. Among the materials tested, Fe3O4@SiO2@4-PCA exhibited the highest xylene adsorption capacity of 649 mg/g, significantly outperforming Fe3O4 (251 mg/g) and Fe3O4@SiO2 (372 mg/g). Kinetic studies indicated that the pseudo-second order model best described the adsorption process, while isotherm analysis showed a strong fit with the Langmuir model, suggesting a favorable physical adsorption mechanism. It was highlighted that the adsorption mechanism of xylene on Fe3O4@SiO2@4-PCA NCs can be attributed to electrostatic interactions, hydrogen interactions, dipole-dipole interactions, van der Waals interactions, functional groups and hydrogen bonding. Additionally, re-usability tests demonstrated that Fe3O4@SiO2@4-PCA maintained 90.48 % of its re-use efficiency after five cycles, highlighting its stability and practical applicability. The enhanced adsorption performance is attributed to the hierarchical modification and surface functionalization with 4-piperidinecarboxylic acid (4-PCA), which increases the active sites and interactions with xylene. Fe3O4@SiO2@4-PCA demonstrated exceptional potential as an adsorbent for xylene, with superior performance compared to existing materials. These findings suggest that Fe3O4@SiO2@4-PCA NCs are promising candidates for VOC removal in industrial applications, offering a sustainable approach to reducing air pollution and protecting the environment.