静电层层自组装法制备磁性吸附剂及其对水溶液中染料的去除

发布时间：2018-08-30 20:02

【摘要】：随着现代工业的迅猛发展,有机合成染料广泛应用于纺织印染、塑料、造纸等行业。然而,由于具有高毒性和致癌性,这些工业生产中产生的染料废水给人类和生态系统带来了日益严重的危害和污染。因为大部分染料具有抗氧化、难降解的特征,所以吸附法在染料污水处理中具有潜在的应用价值。由于层层自组装法制备工艺简单、载体多功能化的特点已在药物释放、催化、生物传感器方面得到了广泛应用。在本论文中,采用层层自组装方法设计合成了两种新型磁性吸附剂,并且进一步研究了他们对于染料的吸附性能及吸附机理。主要研究结果如下:(1)利用层层自组装方法合成两种新型磁性吸附剂:将两种带有相反电荷的聚电解质:壳聚糖和聚丙烯酸通过静电作用交替沉积在磁性微球表面上,制备了Na-(CS/PAA)n/MPC吸附剂,同理将两种带有相反电荷的聚电解质:海藻酸钠和聚乙烯亚胺交替沉积在磁性微球上,合成了(ALG/PEI)n/MN吸附剂。并对合成的吸附剂进行了红外光谱、场发射扫描电镜、热重、X-射线衍射和磁学特性分析.(2)Na-(CS/PAA)n/MPC对于阳离子型染料亚甲基蓝(MB)和结晶紫(CV)的吸附量与(CS/PAA)层数呈线性增加关系。Na-(CS/PAA)4/MPC在25 oC,pH=8时对MB和CV的最大饱和吸附量分别为305.8和243.6 mg g-1。动力学和等温吸附模型结果表明吸附过程是均相单层化学吸附过程,且吸附平衡时间与聚电解质层数无关。热力学结果表明Na-(CS/PAA)4/MN吸附MB与CV的过程是吸热的,而且该吸附剂具有很好的重复利用性。(3)(ALG/PEI)n/MN对于酸性橙10(AO10)的吸附量与(ALG/PEI)层数是正相关关系。(ALG/PEI)4/MN在25 oC,pH=3时对AO10的最大饱和吸附量为246.3 mg g-1。动力学、等温吸附和热力学的结果表明吸附过程是均相单层化学吸附的放热过程,且吸附平衡时间随聚电解质层数的增加而增加。另外,它对AO10也展示出比较好的重复使用性能。
[Abstract]:With the rapid development of modern industry, organic synthetic dyes are widely used in textile printing, dyeing, plastics, papermaking and other industries. However, because of its high toxicity and carcinogenicity, dyestuff wastewater from these industrial production has brought more and more serious harm and pollution to human beings and ecosystem. Because most dyes have the characteristics of oxidation resistance and hard degradation, adsorption method has potential application value in dye wastewater treatment. Because of its simple preparation process and multifunctional carrier, it has been widely used in drug release, catalysis and biosensor. In this paper, two new magnetic adsorbents were designed and synthesized by layer-by-layer self-assembly method, and their adsorption properties and adsorption mechanism for dyes were further studied. The main results are as follows: (1) two new magnetic adsorbents were synthesized by layer-by-layer self-assembly method. Two kinds of polyelectrolyte with opposite charge: chitosan and polyacrylic acid were deposited on the surface of magnetic microspheres alternately by electrostatic interaction. Na- (CS/PAA) n/MPC adsorbents were prepared and (ALG/PEI) n/MN adsorbents were synthesized by alternately depositing two polyelectrolytes with opposite charge: sodium alginate and polyethyleneimide on magnetic microspheres. The synthesized adsorbents were characterized by infrared spectroscopy, field emission scanning electron microscopy, (2) the adsorption capacity of Na- (CS/PAA) n/MPC for cationic dye methylene blue (MB) and crystal violet (CV) was linearly increased with the number of (CS/PAA) layers. The maximum saturated adsorption amounts of MB and CV for CS/PAA 4/MPC were 305.8 and 243.6 mg g-1 at 25 oC,pH= 8, respectively. The results of kinetic and isothermal adsorption models show that the adsorption process is homogeneous monolayer chemisorption process and the adsorption equilibrium time is independent of the number of polyelectrolyte layers. The thermodynamic results show that the adsorption of MB and CV by Na- (CS/PAA) 4/MN is endothermic, and the adsorbent has good reusability. (3) the adsorption capacity of (ALG/PEI) n/MN for acid orange 10 (AO10) is positively correlated with the number of (ALG/PEI) layers. (ALG/PEI) 4/MN 's maximum saturated adsorption capacity for AO10 is 246.3 mg g-1 at 25 oC,pH= 3. The results of kinetics, isothermal adsorption and thermodynamics show that the adsorption process is the exothermic process of homogeneous monolayer chemisorption, and the adsorption equilibrium time increases with the increase of the number of polyelectrolyte layers. In addition, it also shows good reuse performance to AO10.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X703;TQ424

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