麦秆水凝胶的制备及其对Cu(Ⅱ)、Mn(Ⅱ)的吸附

Preparation of Wheat Straw Hydrogel and Its Adsorption Performance for Cu(Ⅱ) and Mn(Ⅱ)

关键词:  麦秆  水凝胶  重金属  吸附

Key Words:wheat straw  hydrogel  heavy metal ions  adsorption properties

摘要:以麦秆为原料，通过自由基接枝共聚反应制备对Cu(Ⅱ)、Mn(Ⅱ)具有高效吸附性能的麦秆水凝胶。实验中先将麦秆粉碎成粉，用氢氧化钠溶液超声纯化，然后以过硫酸铵为引发剂，以丙烯酸和丙烯酰胺为单体，以N,N-亚甲基双丙烯酰为交联剂，得到麦秆水凝胶。通过傅里叶红外光谱仪（FT-IR）、扫描电子显微镜（SEM）、热重分析仪（TGA）等对水凝胶进行表征，并研究其对Cu(Ⅱ)、Mn(Ⅱ)等重金属离子的吸附性能。结果表明，通过FT-IR和SEM分析显示麦秆水凝胶成功制备；麦秆水凝胶对Cu(Ⅱ)、Mn(Ⅱ)具有良好的吸附性能，吸附过程符合准二级动力学模型，在Cu(Ⅱ)、Mn(Ⅱ)离子浓度分别为500 mg/L和400 mg/L，振荡吸附6 h后吸附量分别达到238.1 mg/g和176.9 mg/g。

Abstract:Wheat straw hydrogel with high adsorption capacity for Cu(II) and Mn(II) was prepared by using wheat straw as raw material via free radical graft copolymerization. In the experiment, the wheat straw was first pulverized into powder and ultrasonically purified with sodium hydroxide solution. Then, the wheat straw hydrogel was obtained by graft copolymerization using ammonium persulfate as an initiator, acrylic acid and acrylamide as monomers, and N,N-methylenebisacryloyl as a crosslinking agent. The hydrogels were characterized by fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and thermogravimetry (TGA), and its adsorption properties for heavy metal ions such as Cu(II) and Mn(II) were studied. The results of FT-IR and SEM analysis confirmed the wheat straw hydrogel had been successfully prepared. Wheat straw hydrogel had good adsorption properties for Cu(II) and Mn(II), and the adsorption process conformed to the quasi-secondary kinetic model. When the ion concentrations were 500 mg/L and 400 mg/L and shaking adsorption time was 6 h, the ion adsorption amounts reached 238.1 mg/g and 176.9 mg/g, respectively.