Uniform magnetic chitosan microspheres with radially oriented channels by electrostatic droplets method for efficient removal of Acid Blue

Abstract Chitosan is highly suitable for removing dyes from water, however, their sorption performance, stability and recycling are still critical issues in practical applications. In this work, porous magnetic chitosan microspheres were synthesized by electrostatic droplets (ESD) technology combining chemical crosslinking process. To better prepare the Fe3O4/chitosan hydrogel microspheres during the ESD process, sodium hydroxide was used for solidification of chitosan and the co-precipitation of ferro-gels containing ferrous and ferric cations, and glutaraldehyde was used as a crosslinking agent to fabricate the Fe3O4 nanoparticles embedded porous chitosan microspheres (Fe3O4/PCSM). The Fe3O4/PCSM was characterized by SEM, XRD, EDS, and TEM, and the feasibility for the adsorption of dyes by the composite was investigated systematically. The adsorption capacity of Fe3O4/PCSM for Acid Blue is determined as high as 142 mg g−1, which is comparable to some previous adsorbents. The adsorption isotherm and the adsorption kinetics can be well stimulated by the Langmuir model and the pseudo-second-order kinetic model, respectively. Moreover, the regeneration of used Fe3O4/PCSM is very easy and the recycled materials are efficient for the dyes removal in four cycles.