Fe3O4@SiO2-Chitosan的制备及其对水中Cu2+的吸附效能研究

以SiO_2包覆Fe_3O_4,戊二醛为交联剂,交联壳聚糖(Chitosan, CTS),制得Fe_3O_4@SiO_2-Chitosan复合磁性纳米粒子.以Fe_3O_4和Fe_3O_4@SiO_2为对照,采用X射线衍射、透射电镜和傅立叶红外光谱对其进行表征分析,并测定了投加量、pH值、吸附时间和温度等因素对Cu~(2+)吸附效果的影响,从动力学、热力学以及再生回用性能评价等方面对其吸附性能进行了探究.结果表明Fe_3O_4@SiO_2-Chitosan对Cu~(2+)的吸附过程符合准二级吸附动力学模型和Langmuir模型,为自发、放热、优惠型的单分子层化学吸附.在pH为6.0, 298 K下达到最大吸附量154.8 mg·g~(-1),吸附解吸4次后吸附容量变化不大,说明Fe_3O_4@SiO_2-Chitosan具有较高的吸附容量,可作为处理含铜废水和回收铜的高效吸附剂.

Preparation of Fe3O4@SiO2-Chitosan and its adsorption properties for copper ions in water

Fe₃O₄@SiO₂-Chitosan magnetic nanoparticle compounds were prepared by coating both of Fe₃O₄ with SiO₂ and Chitosan (CTS) crosslinked with glutaraldehyde (GTA). Compared with Fe₃O₄, Fe₃O₄@SiO₂, Fe₃O₄@SiO₂-Chitosan was characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and the effect of adsorbent dose, solution pH, adsorption time and temperature on Cu²⁺adsorption were investigated. Besides, the adsorption properties of Fe₃O₄@SiO₂- Chitosan were implemented from three aspects:adsorption kinetics, thermodynamics and reusability evaluation. The results show that pseudo-second-order kinetics model and Langmuir isotherm model are more suitable for describing the adsorption of Cu²⁺on Fe₃O₄@SiO₂- Chitosan, suggesting that the adsorption process is a spontaneous, exothermic and preferential monolayer chemisorption. At pH 6.0 and 298 K,the maximum adsorption capacity of Cu²⁺ is reported at 154.80 mg·g^-1. After desorption and regeneration for more than four cycles, the adsorption capacity has been maintained the same and there is no significant change. This can be inferred that Fe₃O₄@SiO₂-Chitosan can be used as a high-efficiency adsorbent for the removal and recycle of copper from copper-containing wastewater.