不同尺寸改性果胶基磁性微球的制备及对Pb^(2+)吸附性能的研究

Preparation and Pb^(2+)Adsorption Properties of Modified Pectin-based Magnetic Microspheres with Different Sizes

本工作以乙二胺改性果胶为基质,将其与海藻酸钠、Fe_(3)O_(4)进行复配,采用微胶囊造粒仪制备了不同尺寸(750μm、540μm、400μm、100μm)的改性果胶基磁性微球。通过红外光谱、热重分析、扫描电子显微镜和显微镜分析对样品进行了表征,并研究了不同尺寸的改性果胶基磁性微球对Pb^(2+)的吸附性能。结果表明,100μm的改性果胶基磁性微球达到吸附平衡仅需要1 h。动力学模拟结果表明,吸附更符合准二级动力学模型,吸附速率受化学吸附控制。Langmuir模型可以较好地拟合实验结果,最大吸附容量为256.41 mg/g。解吸再生实验结果表明,100μm的改性果胶基磁性微球经过九次解吸循环再生,去除率无明显下降。

The ethylenediamine modified pectin was used as matrix,compounded with sodium alginate and Fe_(3)O_(4)to synthesize modified pectin-based magnetic microspheres with different sizes(750μm,540μm,400μm and 100μm)by microcapsule encapsulator.The samples were cha-racterized by Fourier transform infrared spectroscopy(FTIR),thermogravimetric analysis(TGA),scanning electron microscopy analysis(SEM)and electron-microscopic analysis.The Pb^(2+)adsorption properties of modified pectin-based magnetic microspheres with different sizes were then studied.The results showed that the adsorption equilibrium of Pb^(2+)on the modified pectin-based magnetic microspheres(100μm)only need 1 h.Kinetics of Pb^(2+)adsorption process were better described by the pseudo-second-order kinetic equation,indicating that the adsorption rate is controlled by chemical adsorption.Langmuir model could better fit the experimental results,and the maximum adsorption capacity of the modified pectin-based magnetic microspheres(100μm)was 256.41 mg/g.The desorption and regeneration experiment showed that the modified pectin-based magnetic microspheres(100μm)exhibited great regeneration ability after nine desorption cycles.