基于仿生结构设计的多孔壳聚糖材料的制备与性能研究

Chitosan is an extensive, non-toxic, biodegradable absorbing material, its application in wastewater treatment is limited due to small specific surface-area and poor mechanical properties. Based on the principle of bionics, the model of honeycomb and diatoms, and chitosan powder as raw material, honeycomb porous layered chitosan material and diatom porous spherical chitosan material were prepared by using the methods of situ precipitation and freeze drying, in order to improve the adsorption capacity and mechanical strength of chitosan materials and achieve its efficient adsorption of heavy metal ions and organic dyes in industrial wastewater. The main contents include: ① clarify the effects of preparation conditions on properties and microstructure of bionic chitosan materials and determine the optimum preparation conditions; ② reveal the relationship between bionic structure design and the degree of crosslinking modification and mechanical strength, thermal stability, water absorption and acid resistance of bionic chitosan materials; ③ analyze the effects of microstructure and properties of bionic chitosan materials on adsorption properties before and after crosslinking modification and its mechanism involved. The project proposes the preparation methods of porous layered and porous spherical chitosan materials based on bionic structure design, without changing the main chemical components of chitosan materials, which provides theory and practice basis for designing, developing and preparing the required chitosan adsorption materials.

壳聚糖作为一种来源广泛、无毒、可生物降解吸附材料，因比表面积小和机械性能欠佳限制了其在废水处理上的应用。本项目基于仿生学原理，以蜂窝和硅藻结构为模型，壳聚糖粉末为原料，采用原位沉析法和冷冻干燥法制备仿蜂窝多孔层状壳聚糖材料和仿硅藻多孔球状壳聚糖材料，以提高壳聚糖材料的吸附容量和机械强度等，实现其高效吸附工业废水中的重金属离子和有机染料。研究内容主要包括：①阐明材料制备条件对仿生壳聚糖材料性质和微观结构的影响及规律，确定材料最佳制备条件；②揭示仿生结构设计和交联改性程度与仿生壳聚糖材料机械强度、热稳定性、吸水性和耐酸性等性能的关系；③分析交联改性前后仿生壳聚糖材料微观结构和性质对材料吸附性能的影响及其所涉及的机理。本项目拟在不改变壳聚糖材料主要化学成分的条件下，提出一种基于仿生结构设计制备多孔层状和多孔球状壳聚糖材料的技术方法，为设计、开发和制备所需性能的壳聚糖吸附材料提供理论和实践依据。

随着工业化水平的不断发展和城市化进程的不断加快，工业和生活废水中日益增加的有毒重金属离子和有机染料等污染物直接威胁着全球生态环境和人类健康。壳聚糖及其衍生物表面大量的氨基、羟基等功能团能够有效地通过静电吸附、螯合等作用去除废水中的重金属离子和有机染料，因此壳聚糖吸附剂在水处理方面得到越来越多的重视和应用。但是由于天然状态的壳聚糖大部分为粉末状，比表面积小，作为吸附载体时，载体和吸附物都难以回收，从而限制了壳聚糖在废水处理中的应用。本项目以天然可再生聚合物壳聚糖为原料，成功制备出仿生壳聚糖多孔球状和层状材料。考查了壳聚糖浓度、固化剂浓度、交联剂浓度、交联时间、冷冻温度和时间等对仿生材料性能和微观结构的影响。分析了吸附体系pH值、离子浓度等对仿生材料吸附能力的影响。相比于壳聚糖微球，仿生壳聚糖多孔球状材料的吸附性能显著提高；同时交联改性显著提高了仿生壳聚糖多孔球状材料的机械强度和耐酸性。本项目制备的仿生壳聚糖多孔材料通过络合及离子交换的作用，对染料、蛋白质、氨基酸、核酸、酶、卤素等进行吸附，可以用于染料废水、印染废水、食品工业废水的处理，从而净化环境，保护人类健康。