Preparation of Magnetic Hemicellulosic Composite Microspheres and Adsorption of Copper Ions

In this study, the fabrication of magnetic hemicellulosic composite microspheres and the adsorption of copper ions are explored. The microspheres were prepared by the micro-emulsion technique, using Fe₃O₄ nanoparticles and hemicellulose extracted from wheat straw with the ionic liquid B[mim]Cl as a solvent. Fe₃O₄ nanoparticles, synthesized through coprecipitation, were evenly encapsulated within the hemicellulosic microspheres. The Fe₃O₄ nanoparticles measured 10-15 nm in size, while the microspheres had an average diameter of about 20 μm and displayed a saturation magnetization of 35.95 emu/g. The optimal conditions for copper adsorption by the microspheres were found to be a pH of 5.0, a temperature of 323 K, and an initial copper ion concentration of 80 mg/L, resulting in an adsorption capacity of 85.65 mg/g after 24 h. The adsorption kinetics followed a pseudo-second-order model, and the Langmuir isotherm suggested a monomolecular layer adsorption mechanism, with a theoretical maximum capacity of 149.25 mg/g. In summary, the magnetic hemicellulosic microspheres exhibited considerable adsorption potential and favorable recycling capabilities for copper ions.