SDS 改性磁性壳聚糖对泰乐菌素和 Cu(Ⅱ)的吸附特性

文章利用共沉淀和水热法制备磁性壳聚糖(magnetic chitosan nanoparticle, MCNP), 并将十二烷基硫酸钠(sodium dodecyl sulfate, SDS)包覆在该吸附剂表面, 形成半胶束和吸附胶团; 研究改性前后 MCNP 对泰乐菌素(tylosin, TYL)和 Cu(Ⅱ)的吸附行为, 利用傅里叶变换红外光谱仪(Fourier transform infrared spectrometer, FTIR)、扫描电子显微镜(scanning electron microscope, SEM)、X 射线衍射仪(X-ray diffractometer, XRD)和 Zeta 电位仪等表征手段对材料的理化性质进行表征, 并考察 pH 值、背景电解质浓度等因素对吸附过程的影响。结果表明: 采用准二级动力学模型可以较好地模拟 TYL 和 Cu(Ⅱ)的吸附过程, 化学吸附可能是吸附剂吸附 TYL 和 Cu(Ⅱ)的主要速率限制步骤; Freundlich 模型更适合模拟 TYL 的吸附过程, 该吸附过程为非均相作用; Langmuir 模型更适合模拟 Cu(Ⅱ)的吸附过程, 该吸附过程为均相作用; pH=4 是 TYL 吸附的最佳 pH 值, pH=6 是 Cu(Ⅱ)吸附的最佳 pH 值; 随着背景电解质浓度增加, MCNP 对 TYL 和 Cu(Ⅱ)的吸附量增加; TYL 的存在显著提高了 Cu(Ⅱ)的吸附性能, 这是由于 TYL 在 Cu(Ⅱ)和 MCNP 之间形成了桥接作用。研究结果可为 TYL 和 Cu(Ⅱ)混合废水的高效深度处理提供参考。

In this paper, magnetic chitosan nanoparticles (MCNP) were prepared by co-precipitation and hydrothermal method. In addition, the anionic surfactant sodium dodecyl sulfate (SDS) was coated on the surface of the adsorbent to form hemimicelles and admicelles. The adsorption performance of MCNP before and after SDS modification for thylosin (TYL) and Cu(Ⅱ) was studied. The physical and chemical properties of materials were characterized by Fourier transform infrared spectrometer (FTIR), scanning electron microscope (SEM), X-ray diffractometer (XRD) and Zeta potentiometer. The results showed that the adsorption process of TYL and Cu(Ⅱ) could be better simulated by the pseudo-second-order kinetic model, indicating that the chemical adsorption was the main rate limiting step. Freundlich isotherm model was fitted well to the equilibrium data of TYL, indicating that the adsorption process was a heterogeneous interaction. Langmuir isotherm model was fitted well to the equilibrium data of Cu(Ⅱ), indicating that the adsorption process was a homogeneous interaction.