Amino-functionalized core-shell magnetic nanocomposites: synthesis, characterization, and adsorption mechanism towards bisphenol A in water

As a well-known hazardous emerging contaminant, the ubiquity of bisphenol A (BPA) in environment has long been a serious problem, and there is an imperative need to reduce BPA toxicity. For aims of efficient BPA removal and breaking the limitations of conventional adsorption processes and adsorbents, amino-functionalized magnetic porous nanocomposites (NH2-MZFS) were synthesized via a modified St & ouml;ber sol-gel method, characterized and used to investigate behaviors of BPA adsorption. The results of characterization showed successful amino-functionalization and that the as-prepared nanocomposites with a regular morphology and mesoporous structure possessed a specific surface area of 121 m2 g-1 and saturation magnetization of 5.54 emu g-1. And the results of BPA adsorption indicated that the adsorption process reached the equilibrium of 28.25 mg g-1 in 30 min at 308 K, was best described by pseudo-second-order kinetic model and Langmuir isotherm model, and was spontaneous and exothermic in nature. Besides, the results of mechanism investigation depicted that, compared with the phenolic hydroxyl groups and benzene rings of BPA, hydroxyl groups and amino groups of NH2-MZFS participated in BPA adsorption with driving forces containing intermolecular hydrogen bonding, coordination, conjugation, electrostatic interaction and so on. In the constructed heterogeneous Fenton-like system, the used NH2-MZFS can be regenerated in-situ and reused with high regeneration efficiency of 72.73% after five runs. These findings suggest that NH2-MZFS could be a promising material for pollution treatment, and can provide a critical theoretical reference to the Bisphenols treatment and material application.