多孔交联壳聚糖吸附剂的制备与吸附性能研究

发布时间：2018-06-06 12:45

本文选题：多孔 + 交联壳聚糖　；参考：《沈阳理工大学》2015年硕士论文

【摘要】：染料废水、重金属离子废水和含酚有机废水等工业废水严重污染环境、危害人类健康,成为现阶段国内外必须面对的一个巨大挑战。本研究在前人研究的基础上,采用天然高分子材料壳聚糖为母体,通过致孔、交联、接枝等处理方法,制备出多孔交联壳聚糖,对其进行了表征和吸附性能的研究。考察了制备条件、静态吸附条件对吸附效果的影响,探讨了对染料、重金属离子和苯酚的吸附机理,为工业废水的处理提供了一定的理论依据和技术支持。以壳聚糖为原料,通过无水乙醇致孔,甲醛预交联、环氧氯丙烷交联,经酸处理制备出多孔交联壳聚糖,考察制备条件和吸附条件对染料吸附性能的影响。结果表明:亚甲基蓝和酸性大红的吸附过程,可用Langmuir方程能更好拟合,吸附过程是吸热过程;吸附动力学符合拟二级动力学模型,且吸附活化能小于41.9 k J/mol,亚甲基蓝染料的吸附主要是物理吸附,酸性大红的吸附为化学吸附。表征显示:吸附剂具有多孔结构,比表面积较壳聚糖显著增大,环氧氯丙烷交联成功。吸附剂再生后,重复使用四次,吸附量没有明显下降。以聚乙二醇2000为致孔剂,甲醛预交联、环氧氯丙烷交联,接枝三乙烯四胺,酸洗后制备出三乙烯四胺接枝多孔交联壳聚糖吸附剂,对其表征;考察制备条件和吸附条件对Pb2+和Au3+吸附性能的影响,初步探讨了吸附机理,结果表明:吸附剂表面孔增加,比表面积增大;环氧氯丙烷与壳聚糖的氨基和羟基交联,三乙烯四胺接枝在交联壳聚糖上;Pb2+和Au3+的吸附过程,均可用Langmuir方程拟合,Au3+和Pb2+的吸附分别为吸热和放热过程;Pb2+和Au3+的吸附动力学符合拟二级动力学模型,且以化学吸附为主。重复使用5次,吸附量变化不大。以无水乙醇致孔,甲醛预交联、环氧氯丙烷交联,接枝乙二胺,酸处理后制备出乙二胺接枝多孔交联壳聚糖吸附剂,考察了制备条件和吸附条件对苯酚吸附性能的影响,结果表明:吸附剂表面形成了空穴和孔道,比表面积增大,壳聚糖的氨基参与交联反应,生成希夫碱,羟基没有参与交联反应。吸附过程可用Freundlich方程更好的拟合,且为吸热过程;吸附动力学符合拟二级动力学模型,吸附活化能小于41.9 k J/mol,吸附可在室温下进行,且具有良好的再生性。
[Abstract]:Industrial wastewater, such as dye wastewater, heavy metal ion wastewater and organic wastewater containing phenols, seriously pollutes the environment and endangers human health, which has become a great challenge that must be faced at home and abroad at present. On the basis of previous studies, the porous cross-linked chitosan was prepared by using the natural polymer chitosan as the matrix. The porous chitosan was characterized and its adsorption properties were studied by means of pore formation, crosslinking and grafting. The effects of preparation conditions and static adsorption conditions on adsorption efficiency were investigated. The adsorption mechanism of dyes, heavy metal ions and phenol was discussed, which provided a theoretical basis and technical support for the treatment of industrial wastewater. Porous cross-linked chitosan was prepared by acid-treatment with anhydrous ethanol-induced pore, formaldehyde precrosslinking and epichlorohydrin crosslinking. The effects of preparation conditions and adsorption conditions on the adsorption properties of dyes were investigated. The results show that the adsorption process of methylene blue and acid scarlet can be better fitted by Langmuir equation, the adsorption process is endothermic process, and the adsorption kinetics accords with the pseudo-second-order kinetic model. The adsorption activation energy is less than 41.9 k / mol. The adsorption of methylene blue dye is mainly physical adsorption, and the adsorption of acid scarlet is chemisorption. The results showed that the adsorbent had porous structure, its specific surface area was significantly larger than that of chitosan, and the crosslinking of epichlorohydrin was successful. After regeneration, the adsorbent was reused for four times, and the adsorption capacity did not decrease significantly. Using polyethylene glycol 2000 as pore-forming agent, formaldehyde precrosslinking, crosslinking of epichlorohydrin and grafted triethylenetetramine, a porous chitosan adsorbent was prepared by acid washing and characterized. The effects of preparation conditions and adsorption conditions on the adsorption properties of Pb2 and Au3 were investigated. The adsorption mechanism was preliminarily discussed. The results showed that the surface pores of adsorbent increased and the specific surface area increased, and the amino and hydroxyl groups of epichlorohydrin and chitosan were crosslinked. The adsorption process of Pb _ 2 and Au3 on cross-linked chitosan by grafting triethylenetetraamine with triethylenetetraamine can be fitted by Langmuir equation. The adsorption kinetics of Au3 and Pb2 is endothermic and exothermic respectively. The adsorption kinetics of Pb2 and Au3 accords with the pseudo-second-order kinetic model, and chemisorption is the main one. After repeated use for 5 times, the adsorption amount did not change much. Porous chitosan adsorbents were prepared by acid-treatment of ethylenediamine, precrosslinked with formaldehyde, crosslinking of epichlorohydrin, grafting of ethylenediamine with anhydrous ethanol. The effects of preparation conditions and adsorption conditions on the adsorption properties of phenol were investigated. The results showed that holes and pores were formed on the surface of the adsorbent and the specific surface area was increased. The amino group of chitosan participated in the crosslinking reaction to form Schiff base and the hydroxyl group did not participate in the crosslinking reaction. The adsorption process can be fitted better by Freundlich equation and is an endothermic process. The adsorption kinetics accords with the pseudo-second-order kinetic model, the adsorption activation energy is less than 41.9 kJ / mol, the adsorption can be carried out at room temperature and has good regeneration.
【学位授予单位】：沈阳理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ424;X703

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