Core–shell structured Fe3O4/PANI microspheres and their Cr(VI) ion removal properties

Magnetic composite microspheres present a promising candidate for applications in water treatment, enzyme immobilization, drug delivery, catalysis, and sensors. In this paper, we report on the surfactant-free synthesis of well-defined Fe3O4/PANI microspheres through an interfacial polymerization approach. The as-prepared magnetic composite spheres show good dispersion, core–shell structure, and high magnetization. Also, the Fe3O4/PANI microspheres were tested as an adsorbent to remove Cr(VI) ions from water, and were found to have a strong adsorption capacity of ca. 200 mg g−1. The adsorption isotherm for Cr(VI) adsorption on Fe3O4/PANI microspheres follows the Langmuir isotherm model, and the adsorption process meets the pseudo-second-order kinetics. After reuse five times, the adsorption capacity of Fe3O4/PANI microspheres retains 90% of the initial value, indicating that the Fe3O4/PANI microspheres can serve as an excellent regenerable Cr(VI) adsorbent.

Graphical abstractCore–shell structured Fe3O4/PANI microspheres were constructed by an interfacial polymerization approach without surfactant, which were found to be an excellent regenerable adsorbent to offer rapid Cr(VI) ion removal from water within 30 min.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Core–shell structured Fe3O4/PANI microspheres were constructed without surfactant. ► The composite spheres have a strong Cr(VI) ion adsorption capacity of ca. 200 mg g−1. ► The composite spheres show an excellent regenerability after reuse five times. ► The composite spheres offer rapid Cr(VI) ion removal from water within 30 min. ► The Cr(VI) adsorption isotherm follows the Langmuir isotherm model.