磁性氨基酸功能化海藻酸铝凝胶聚合物的制备及对偶氮染料的超强吸附

Preparation of Magnetic Amino Acid-Functionalized Aluminum Alginate Gel Polymer and its Super Adsorption on Azo Dyes

以海藻酸钠为原料,采用液滴聚合法将其与Al(Ⅲ)离子交联并引入甘氨酸和Fe_(3)O_(4),制备出磁性氨基酸功能化海藻酸铝凝胶聚合物(Gly/Al/SA@Fe_(3)O_(4)),使用扫描电镜(SEM)、X射线能谱仪(EDS)、傅里叶红外光谱仪(FT-IR)、X射线衍射仪(XRD)和振动样品磁强计(VSM)等手段对其表征,研究了这种凝胶聚合物对偶氮染料的吸附性能。结果表明,Gly/Al/SA@Fe_(3)O_(4)是一种表面具有花式褶皱结构的三维网状聚合物颗粒,其磁响应能力良好。Gly/Al/SA@Fe_(3)O_(4)对水体中直接黑19(DB 19)和直接棕2(DB 2)染料的吸附性能超强,吸附速率极高,吸附15 min和60 min达到动态平衡的吸附量分别为2500和3126 mg/L。吸附过程可用拟二级速率方程描述,等温吸附数据符合Langmuir模型。吸附剂与染料分子间的相互作用通过静电吸附、氢键作用、配体交换和化学吸附协同实现。Gly/Al/SA@Fe_(3)O_(4)颗粒绿色环保,对高浓度偶氮染料废水有超强的净水性能,并可用磁场进行快速固液分离。

A novel magnetic amino acid functionalized aluminum alginate gel polymer Gly/Al/SA@Fe_(3)O_(4) was prepared via droplet polymerization technique with sodium alginate(SA)as raw material,which was crosslinked with Al(Ⅲ)ions,while glycine(Gly)and Fe_(3)O_(4) were simultaneously added.The prepared Gly/Al/SA@Fe_(3)O_(4) was characterized by means of scanning electron microscopy(SEM),X-ray energy dispersive spectroscopy(EDS),Fourier infrared spectroscopy(FT-IR),X-ray diffractometer(XRD)and vibrating sample magnetometer(VSM).Its absorption performance for azo dyes was also investigated.The results show that Gly/Al/SA@Fe_(3)O_(4) is a kind of three-dimensional network-like polymer particles with a fancy fold structure on the surface,and its magnetic response ability is good.Gly/Al/SA@Fe_(3)O_(4) shows strong adsorption performance with high adsorption rate for Direct Black 19(DB 19)and Direct Brown 2(DB 2)dyes in water.The dynamic equilibrium adsorption capacities reached 2500 mg/L and 3126 mg/L,respectively for the above two dyes in 15min and 60 min.The adsorption process can be described by a quasi-second-order rate equation,and the isothermal adsorption data conform to Langmuir model.The interaction between the adsorbents and dye molecules was synergistic through electrostatic adsorption,hydrogen bonding,ligand exchange and chemisorption.Gly/Al/SA@Fe_(3)O_(4) particles are green and environment-friendly,and have strong water purification ability for wastewater containing high concentration azo dye,therefore,it can be used for rapid solid-liquid separation with magnetic field.