【作者】 赵静；

【导师】 张煊；

【作者基本信息】 东华大学 ， 化学， 2025， 硕士

【摘要】 随着社会进步,工业化进程加速,生态系统承载的压力持续加剧,其中水环境引发的生态链毒素累积效应直接威胁区域生态安全和公共卫生。因此,治理水污染已成为保障环境安全与人类可持续发展的重中之重。在废水处理技术领域,吸附、膜分离、沉淀及光催化等物理化学方法是研究热点。吸附法作为去除水中污染物最简便、应用最广的技术之一,以其操作便捷、效率高、技术门槛低、成本少、回收易及环保等优势受到青睐。天然高分子材料壳聚糖(CS),凭借优异的生态相容性及多重结合位点特性,在水体净化领域具有重要应用价值。然而其固有的力学稳定性不足、重复利用效率低下及吸附容量受限等缺陷,导致实际环境治理中面临多重应用瓶颈。基于此,研究方向聚焦于强化骨架结构稳定性、提高污染物吸附效率以及构建高效再生体系。本研究选用CS为原料,引入聚乙烯醇(PVA)构建交联网络以增强其结构强度,在此基础上对壳聚糖进行功能化改性,成功构建了新型壳聚糖基复合材料,采用SEM、XPS、FT-IR等表征手段对复合材料进行表征,评估其对重金属离子和染料的吸附性能,探讨功能化修饰后对吸附选择性和吸附容量的作用机制。(1)以CS和PVA为原料,通过乙醛酸进行交联反应,成功制备了羧基功能化壳聚糖-聚乙烯醇复合材料(PVA-CS-COOH)。实验结果表明,该复合材料对Hg(II)表现出优异的吸附能力。该复合材料的理论饱和吸附容量可达271.00mg/g,经过20次循环稳定性测试,去除率仍保持在90%以上,显示出稳健性和出色的可回收性。吸附动力学和等温线研究表明,PVA-CS-COOH的吸附行为分别与准二级动力学模型和Langmuir模型有较好吻合。通过分析XPS,表明协同配位和静电相互作用在PVA-CS-COOH复合材料上对Hg(II)的吸附中发挥重要作用。(2)采用甲醛为交联剂,将2-巯基苯并噻唑功修饰在壳聚糖上,成功合成了巯基功能化壳聚糖-聚乙烯醇复合材料(PVA-CS-MBT)。该复合材料对Pd(II)显示出具有独特的显色识别能力,在共存离子干扰下依旧能对Pd(II)有特异性显色,证明该材料具有良好的抗干扰性。测试结果显示,该材料对Pd(II)的灵敏度可达5ppm,且经过5次吸附-解吸循环后仍保持稳定的检测性能。吸附实验数据表明,PVA-CS-MBT对Pd(II)的最大吸附容量为31.33 mg/g。通过机理分析可知,S和N原子通过与Pd(II)的配位作用形成稳定结构。(3)采用戊二醛为交联剂,将三聚氰胺成功修饰在CS上,成功制备了三聚氰胺功能化壳聚糖-聚乙烯醇复合材料(PVA-CS-MF)。实验结果表明,该复合材料对活性染料有优异的吸附性能,在298 K、p H=7.0条件下,该复合材料对活性染料RO16和RB5的最大吸附量分别达到425.53 mg/g和469.48 mg/g,其吸附过程遵循准二级动力学模型和Langmuir等温线模型,表明吸附行为是单分子层化学吸附。通过分析XPS,表明静电作用、氢键作用等在PVA-CS-MF复合材料吸附过程中发挥着重要作用。更多还原

【Abstract】 With the progress of society and the acceleration of industrialization,the pressure carried by ecosystems continues to intensify,with water environment deterioration being the most prominent,leading to the accumulation of ecological chain toxins that directly threaten regional ecological security and public health.Therefore,controlling water pollution has become a top priority in ensuring environmental safety and sustainable human development.In the field of wastewater treatment technology,physical and chemical methods such as adsorption,membrane separation,precipitation,and photocatalysis have always been research hotspots.Adsorption method,as one of the simplest and most widely used technologies for removing pollutants from water,is favored for its advantages of convenient operation,high efficiency,low technical threshold,low cost,easy recovery,and environmental protection.Chitosan,a natural polymer material,possesses significant application potential in the realm of water purification,attributed to its exceptional ecological compatibility and multifaceted binding site characteristics.Nevertheless,its inherent limitations,including inadequate mechanical stability,low reutilization efficiency,and constrained adsorption capacity,pose numerous challenges in practical environmental remediation.Consequently,the focus has been directed towards enhancing the structural stability of the scaffold,improving pollutant adsorption efficiency and establishing an efficient regeneration mechanism.This study used CS and PVA as raw materials to functionalize chitosan and prepare functionalized chitosan composite materials.SEM,XPS,FT-IR and other characterization methods were used to evaluate the adsorption performance of the composite materials for heavy metal ions and dyes,and to explore the mechanism on adsorption selectivity and capacity after functionalization modification.(1)Carboxyl functionalized chitosan polyvinyl alcohol composite(PVA-CS-COOH)was successfully prepared by crosslinking CS and PVA with glyoxylic acid.The experimental results showed that the composite exhibited excellent adsorption capacity for Hg(II).The theoretical saturated adsorption capacity of the composite can reach 271.00 mg/g.After 20cycles of stability test,the removal rate remains above 90%,showing excellent recyclability.The adsorption kinetics and isotherm studies showed that the adsorption behavior of PVA-CS-COOH was in good agreement with the quasi second order kinetic model and the Langmuir model,respectively.The analysis of XPS showed that the synergistic coordination and electrostatic interaction played an important role in the adsorption of Hg(II)on PVA-CS-COOH composites(2)Thiol-functionalized chitosan-polyvinyl alcohol composite(PVA-CS-MBT)was synthesized by modifying chitosan with 2-mercaptobenzothiazole using formaldehyde as the crosslinking agent,which shows a unique color recognition ability for Pd(II).Under the interference of coexisting ions,PVA-CS-MBT has good anti-interference performance.The sensitivity of the material to Pd(II)could reach 5 ppm,and the detection performance remained stable after five adsorption-desorption cycles.The maximum adsorption capacity of PVA-CS-MBT for Pd(II)was 31.33 mg/g.According to XPS analysis,S and N atoms form a stable structure through the coordination interaction with Pd(II).(3)Melamine functionalized chitosan polyvinyl alcohol composite(PVA-CS-MF)was successfully prepared by using glutaraldehyde as crosslinking agent and melamine was successfully modified on CS.The experimental results showed that the composite had excellent adsorption performance for reactive dyes.The maximum adsorption capacity of the composite for reactive dyes ro16 and RB5 reached 425.53 mg/g and 469.48 mg/g,respectively.The adsorption process followed the quasi second-order kinetic model and Langmuir isotherm model,indicating that the adsorption behavior was monomolecular layer chemisorption.XPS analysis showed that electrostatic interaction and hydrogen bonding played an important role in the adsorption process of PVA-CS-MF composite.更多还原