Fe₃O₄@SiO₂@CCS porous magnetic microspheres as adsorbent for removal of organic dyes in aqueous phase

A novel Fe₃O₄@SiO₂@carbonized chitosan (Fe₃O₄@SiO₂@CCS) porous magnetic microspheres are prepared through the combination technique of microfluidic, ionic crosslinking and hydrothermal carbonization. Modern characterization analysis shows that Fe₃O₄@SiO₂@CCS microspheres are superparamagnetic and exhibit excellent pore performance. The carbonization time is investigated to study its influence on morphology, pore property, component and magnetic performance. Carbonization reaction is carried out from outside to inside and contained hydration condensation process. The as-obtained microspheres are used as adsorbents for removal of organic dyes from water. It is found that the microspheres prepared at 12 h (MSCCS-12) show greater advantage as the adsorbents. The adsorption isotherms can be fitted with Langmuir equation. The maximum adsorption capacity for RhB on MSCCS-12 estimated from the Langmuir model is 191.57 mg g⁻¹ at 25 °C. A distinct advantage of Fe₃O₄@SiO₂@CCS microspheres is that they can readily be isolated from solutions by application of an external magnetic field. The microspheres exhibit excellent reusability. The removal efficiency retained nearly 90% after fifteen successive cycles of reuse. Thus, the novel adsorbent shows potential application value in removal of organic dyes.