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以球磨后的粉煤灰磁珠(MS)颗粒为磁核,通过溶胶凝胶法和反相微乳液法依次包覆SiO_2和壳聚糖(CS),制备了MS@SiO_2@CS磁性微球。利用扫描电镜及能量色散谱仪、热重分析仪、红外光谱仪、X射线衍射仪、振动样品磁强计对所得样品的结构和磁性进行了系统表征。结果表明,磁珠颗粒表面实现了逐层包覆,较均匀的分散于壳聚糖基体中,MS@SiO_2@CS微球的比饱和磁化强度可达7.04 emu·g~(-1)。Cu~(2+)离子吸附实验表明,所得磁性壳聚糖微球对Cu~(2+)具有良好的吸附能力,最大吸附量可达11.08 mg·g~(-1);而且可通过磁选法高效固液分离。吸附动力学研究表明,MS@SiO_2@CS微球对Cu~(2+)离子的吸附符合准二级动力学模型,以化学吸附为主。
The MS @ SiO_2 @ CS magnetic microspheres were prepared by ball milling the magnetic particles of magnetic beads (MS) as magnetic cores and coating silica and chitosan (CS) sequentially by sol-gel method and reverse microemulsion method . The structure and magnetic properties of the samples were systematically characterized by scanning electron microscopy, energy dispersive spectroscopy, thermogravimetry, infrared spectroscopy, X-ray diffraction and vibrating sample magnetometer. The results showed that the surface of magnetic beads was coated layer by layer and uniformly dispersed in chitosan matrix. The specific saturation magnetization of MS @ SiO_2 @ CS microspheres was 7.04 emu · g -1. Cu 2+ ion adsorption experiments show that the obtained magnetic chitosan microspheres have good adsorption capacity for Cu 2+ with the maximum adsorption capacity of 11.08 mg · g -1. Selection method efficient solid-liquid separation. Adsorption kinetics studies show that adsorption of Cu 2+ ions by MS @ SiO_2 @ CS microspheres accords with quasi-second-order kinetic model, mainly by chemisorption.