明胶/聚乙烯胺凝胶珠的制备及其对Cr(Ⅵ)/ Cu(Ⅱ)的吸附性能
Preparation of GE/PVAm Gel Beads and its Adsorption to Cr(VI)/Cu(II)
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摘要: 以明胶（GE）和两性聚乙烯胺(PVAm）为原料,以戊二醛为交联剂,制备了明胶/两性聚乙烯胺（GE/PVAm）凝胶珠,用于去除水中的Cu（II）和Cr（VI）。采用傅里叶红外光谱仪（FT-IR）分析了GE/PVAm的化学基团结构信息,用扫描电镜（SEM）观察了GE/PVAm的微观结构。吸附实验结果表明,GE/PVAm去除铜离子的最佳pH为6,最大吸附容量分20.44 mg/g;去除六价铬离子的最佳pH为2,最大吸附容量分别18.41 mg/g。吸附热力学研究表明,GE/PVAm对Cu（II）的吸附行为可使用Langmuir吸附等温线模型描述,而Freundlich吸附等温线模型可更好地解释Cr（VI）在GE/PVAm上的吸附行为;Cu（II）及Cr（VI）的吸附动力学均符合准二级动力学模型。Abstract: A novel gel beads (GE/PVAm) composed with gelatin and amphoteric polyvinylamine and cross-linked by glutaraldehyde were prepared in order to remove Cu(II) and Cr(VI) from water. The chemical structures of GE/PVAm were characterized by FT-IR and its microtopography was investigated by SEM. The optimum pH values for removing of Cu(II) was at 6 with a maximal adsorption capacity of 20.44 mg/g, while the optimum pH for Cr(VI) was at 2 with a maximal adsorption capacity of 18.41 mg/g. The adsorption of Cu(II) on GE/PVAm was well fitted by Langmuir adsorption isotherm model, while the adsorption of Cr(VI) on GE/PVAm was described well by Freundlich adsorption isotherm model. Their adsorption kinetics can be described well by the pseudo-second-order model.
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