Magnetite doped metal–organic framework nanocomposites: an efficient adsorbent for removal of bisphenol-A pollutant

Abstract

The removal of bisphenol-A (BPA) from the aqueous environment is a vital issue for public health due to its toxic effect. In this work, variable amounts of the dextran coated-magnetite doped metal–organic framework nanocomposites (MOF:Fe₃O₄@Dex) were successfully prepared and used as an adsorbent for the removal of BPA from aqueous solution. Firstly, dextran-coated magnetite nanoparticles (Fe₃O₄@Dex) were synthesized via the co-precipitation method, and then MIL-100(Fe) nanocomposites (MOF:Fe₃O₄@Dex), including different amounts of Fe₃O₄@Dex nanoparticles, were prepared by the reflux method. The obtained nanocomposites were characterized through Fourier transform infrared spectroscopy, powder X-ray diffraction, thermogravimetric analysis, scanning and transmission electron microscopy, and magnetic and surface measurements. The batch adsorption method was carried out as a function of pH, adsorbent amount, contact time, and initial BPA concentration for the removal of BPA using the MOF:Fe₃O₄@Dex nanocomposite. The adsorption of BPA could be completed within approximately 60 min at room temperature using 300 mg L⁻¹, 100 mL, pH 5 BPA solution. The maximum adsorption capacity of BPA on the MOF:Fe₃O₄@Dex nanocomposite was calculated as 347 mg g⁻¹, which is quite a high value compared to that of the previously reported adsorbents. After five cycles, the adsorption capacity of the MOF:Fe₃O₄@Dex nanocomposite was still retained at a high level. The adsorption kinetics, isotherms, and mechanisms were also investigated. All the results proved that the magnetic nanocomposite (MOF:Fe₃O₄@Dex) could be a potential candidate for water purification applications.