Abstract:

Using sodium alginate hydrogel as skeleton, in combination with chitosan and magnetic Fe₃O₄, a new type of magnetic chitosan/sodium alginate gel bead was prepared. On this basis, through the orthogonal experiment and single-factor experiment, the authors optimized the preparation conditions for composite gel bead, and determined the optimum one. The influences of many preparation impact factors on adsorption performance were examined. Results show that the optimal preparation conditions for the composite gel bead is as follows. Concentration of calcium chloride is 2.5 g/L, concentration of sodium alginate is 24 g/L, the amount of chitosan addition is 5 g/L, and the amount of magnetic liquid addition is 4.64 g/L. The optimal gel bead is a smooth, uniform, black ball with about 2 mm in diameter. By Fourier transform infrared spectroscopy (FTIR), synchronous thermal analysis (TGA) and other means of characterization, the adsorption mechanism is analyzed. Thermogravimetric analysis results show that the gel bead has good thermal stability. FTIR results prove that many active functional groups (amino group, hydroxyl group and carboxyl group) exist on the surface of gel bead. The adsorption performance test shows that adsorption ratio of 20mg MCSB on 40mL 25mg/L Cu²⁺ solution is 78.13%. The magnetic chitosan/sodium alginate gel bead is a novel simple-prepared and effective composite adsorbent.

Key words: sodium alginate gel bead, chitosan, magnetic Fe₃O₄, Cu²⁺

摘要：

以海藻酸钠水凝胶为骨架, 结合壳聚糖和磁性Fe₃O₄, 开发出一种新型的磁性壳聚糖/海藻酸钠复合凝胶球(MCSB)制备方法, 并通过正交试验和单因素实验, 探究不同制备条件对复合凝胶球制备效果的影响, 确定最优制备条件: CaCl₂浓度为2.5 g/L, 海藻酸钠浓度为24 g/L, 壳聚糖添加量为5 g/L, 磁流体添加量为4.64 g/L。制备出的凝胶球表面光滑, 大小均匀, 纯黑色, 呈球形, 直径在2 mm左右, 具有顺磁性。通过傅里叶变换红外光谱(FTIR)、同步热分析(TGA)等手段对凝胶球进行表征。结果表明, MCSB的热稳定性良好, 凝胶球表面的活性基团主要有羟基、氨基、羧基等。吸附性能实验表明, 当MCSB用量为20 mg时, 对40 mL 25 mg/L Cu²⁺溶液的吸附去除率为78.13%, 表明磁性壳聚糖/海藻酸钠复合凝胶球是一种制备简单、效果良好的新型复合吸附剂。

关键词: 海藻酸钠凝胶球, 壳聚糖, 磁性Fe₃O₄, Cu²⁺