PEI改性磁性聚合物吸附剂的合成及重金属离子吸附性能研究

发布时间：2018-07-25 14:40

【摘要】：本文首先采用改良共沉淀法制备Fe_3O_4磁性纳米粒子,然后分别用γ-氯丙基三甲氧基硅烷偶联剂和聚乙烯亚胺(PEI)逐步对磁性纳米粒子进行表面改性,最后将PEI改性磁性纳米粒子与功能性单体进行接枝共聚制备PEI改性磁性聚合物吸附剂,考察了聚合反应参数和吸附条件对PEI改性磁性聚合物吸附剂重金属离子吸附性能的影响,采用多种现代表征手段对磁性吸附剂的结构进行了表征,研究PEI改性磁性聚合物吸附剂重金属离子的吸附动力学和吸附热力学,考察PEI改性磁性聚合物吸附剂的磁响应性、解吸和循环再生利用性能,初步探讨PEI改性磁性聚合物吸附剂对重金属离子的吸附机理,主要研究结果如下:1、XRD表明磁性纳米粒子、硅烷偶联剂改性磁性纳米粒子以及PEI改性磁性纳米粒子的结晶度较高,PEI改性磁性聚合物吸附剂的聚合物基体为非晶态结构,磁性Fe_3O_4以高结晶结构分散于聚合物基体中。2、SEM表明PEI改性磁性聚合物吸附剂表面粗糙不平整,具有较多微孔和连续贯穿的沟壑结构,有利于重金属离子通过快速渗透和扩散进入到PEI改性磁性聚合物吸附剂凝胶网络内部,使PEI改性磁性聚合物吸附剂具有良好的重金属离子吸附性能。3、FTIR表明硅烷偶联剂和PEI接枝到磁性纳米粒子表面,制备的PEI改性磁性聚合物吸附剂具有目标结构。TGA结果表明硅烷偶联剂和PEI接枝到磁性纳米粒子表面,PEI改性磁性聚合物吸附剂具有较高的磁含量和热稳定性。4、磁性纳米粒子分散液、硅烷偶联剂改性磁性纳米粒子分散液和PEI改性磁性纳米粒子分散液均具有快速的磁响应性。磁性纳米粒子的饱和磁化强度达67.76 emu/g,硅烷偶联剂改性磁性纳米粒子和PEI改性磁性纳米粒子的饱和磁化强度略有降低,PEI改性磁性聚合物吸附剂饱和磁化强度降低幅度较大,但仍然具有一定的磁响应性。磁性纳米粒子、硅烷偶联剂改性磁性纳米粒子、PEI改性磁性纳米粒子和PEI改性磁性聚合物吸附剂均具有超顺磁性。5、当丙烯酸/丙烯酰胺质量比为60:40,丙烯酸中和度为70%,交联剂用量为0.75%,引发剂用量为0.8%,PEI改性磁性Fe_3O_4纳米粒子含量为15%,PEI改性磁性聚合物吸附剂重金属离子吸附性能分别达到最大值。6、随着pH和重金属离子初始浓度的增加,PEI改性磁性聚合物吸附剂对重金属离子Cu~(2+)、Cd~(2+)、Pb~(2+)吸附容量均呈现先快速增加然后趋缓的趋势。PEI改性磁性聚合物吸附剂对重金属离子Cu~(2+)、Cd~(2+)、Pb~(2+)的吸附速率较快,吸附45 min重金属离子吸附量趋于平衡。7、PEI改性磁性聚合物吸附剂对重金属离子Cu~(2+)、Cd~(2+)、Pb~(2+)的吸附过程符合Langmuir等温吸附模型和准二级动力学方程。8、经过5次循环再生利用后,PEI改性磁性聚合物吸附剂重金属离子Cu~(2+)、Cd~(2+)、Pb~(2+)的解吸率仍高于85%,重金属离子Cu~(2+)、Cd~(2+)、Pb~(2+)的吸附容量分别为第一次吸附容量的71.6%、72.1%和72.8%。
[Abstract]:In this paper, Fe_3O_4 magnetic nanoparticles were prepared by modified coprecipitation method, and then modified by 纬 -chloropropyl trimethoxysilane coupling agent and polyethylimine (PEI) respectively. Finally, PEI modified magnetic nanoparticles were grafted with functional monomers to prepare PEI modified magnetic polymer adsorbents. The effects of polymerization parameters and adsorption conditions on the adsorption properties of heavy metal ions of PEI modified magnetic polymer adsorbents were investigated. The structure of magnetic adsorbent was characterized by many modern methods. The adsorption kinetics and thermodynamics of heavy metal ions of PEI modified magnetic polymer adsorbent were studied. The magnetic response of PEI modified magnetic polymer adsorbent was investigated. The adsorption mechanism of PEI modified magnetic polymer adsorbents for heavy metal ions was studied. The main results were as follows: 1: 1 PEI showed magnetic nanoparticles. The polymer matrix of magnetic polymer adsorbent modified by silane coupling agent and magnetic nanoparticles modified by PEI was amorphous. Magnetic Fe_3O_4 was dispersed in polymer matrix with high crystalline structure. The results showed that the surface of PEI modified magnetic polymer adsorbent was rough and uneven, with more micropores and continuous trench structure. It is advantageous for heavy metal ions to penetrate into the gel network of PEI modified magnetic polymer adsorbent through rapid permeation and diffusion. The magnetic polymer adsorbents modified by PEI have good adsorption properties of heavy metal ions. 3FTIR showed that silane coupling agent and PEI were grafted onto the surface of magnetic nanoparticles. The PEI modified magnetic polymer adsorbent has the target structure. The results show that the silane coupling agent and PEI grafted onto the surface of magnetic nanoparticles have higher magnetic content and thermal stability. Nanoparticles dispersions, Both silane coupling agent modified magnetic nanoparticles dispersion and PEI modified magnetic nanoparticles dispersion have fast magnetic response. The saturation magnetization of magnetic nanoparticles was 67.76 emu / g. The saturation magnetization of silane coupling agent modified magnetic nanoparticles and PEI modified magnetic nanoparticles decreased slightly. But it still has a certain magnetic response. Magnetic nanoparticles, The magnetic nanoparticles modified by silane coupling agent and the magnetic polymer adsorbent modified by PEI have superparamagnetic properties. When the mass ratio of acrylic acid to acrylamide is 60: 40, the neutralization degree of acrylic acid is 70. 0.75, the amount of initiator is 0.8 and the content of magnetic Fe_3O_4 nanoparticles modified by PEI is 15%. The adsorption properties of heavy metal ions of magnetic polymer adsorbents are respectively up to the maximum of .6. with the increase of pH and the initial concentration of heavy metal ions, the magnetic polymers are modified by PEI-modified magnetic polymers with the increase of pH and initial concentration of heavy metal ions. The adsorption capacity of Cu ~ (2) C ~ (2) O ~ (2) CD ~ (2) and Pb ~ (2) for heavy metal ions increased rapidly and then slowed down. The adsorption rate of Cu ~ (2) C ~ (2) O ~ (2) CD ~ (2) and Pb ~ (2) was higher than that of the magnetic polymer adsorbent modified by PEI. The adsorption capacity of heavy metal ions for 45 min tends to be in equilibrium. The adsorption process of heavy metal ions Cu ~ (2) CD ~ (2) CD ~ (2) Pb ~ (2) is in accordance with the Langmuir isothermal adsorption model and quasi second-order kinetic equation .8. after 5 cycles, the adsorption rate of Cu ~ (2) and CD ~ (2) Pb ~ (2) is reclaimed. The desorption rate of heavy metal Cu ~ (2) O ~ (2) CD ~ (2) Pb2 is still higher than that of 85wt%, and the adsorption capacity of Cu ~ (2) C ~ (2) O ~ (2) Pb ~ (2) is 71.672.1% of the first adsorption capacity and 72.8% of the first adsorption capacity of the heavy metal ion Cu ~ (2) ~ (2) ~ (2) ~ (2) ~ (2) ~ (2) Pb ~ (2).
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O647.33

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