Novel chitosan/GO@Fe3O4 porous microspheres with magnetic separation function for the removal of Congo red from aqueous solutions

Developing a novel chitosan porous microsphere with outstanding adsorption performance and magnetic separation function is significant for recycling and purification in wastewater treatment applications. GO@Fe3O4 (magnetic graphene oxide nanocomposite, MGN) was synthesized by a hydrothermal method, and magnetic chitosan/GO@Fe3O4 porous microspheres (MCMS) were fabricated via inverse emulsion method combined with simple microfluidic technique. The influence of MGN on the microstructures, magnetic separation performance and thermal stability of MCMS was characterized and the efficiency in removing Congo red (CR) from aqueous solutions was evaluated. The incorporation of MGN can significantly improve the adsorption performance of MCMS microspheres. The maximum adsorption amount of MCMS for CR achieved was around 395.8 mg g-1 at 308 K. MCMS also exhibited excellent magnetic separation performance and remarkably enhanced thermal stability. Besides, the pseudo-second-order kinetic model can describe the adsorption process for CR well, and the adsorption isotherms closely obeyed the Langmuir isotherm model.