三维微纳磁性壳聚糖/石墨烯类复合吸附材料的构建及协同增效机制

In addition to the excellent physical and chemical properties, three-dimensional (3D) graphene and its composite adsorptive material have shown some advantages, such as high adsorption capacity, easy control of hydrophilic/hydrophobic property and repeatable use. However, the present researches mainly focus on single pollutant and lack systematic reports about adsorption mechanism. In this project, graphene-like compound was prepared by liquid phase or solid phase method. Then, it was evenly dispersed with iron/ferrous compound and chitosan or its derivatives in water to obtain hydrogel. Next, by suitable aftertreatment (e.g., freeze drying), 3D micro/nano magnetic chitosan/graphene-like composite adsorptive material was acquired. The influence rules of the composition and structure of raw material and technologic parameter on the structure and composition of composite adsorptive material were studied systematically, so as to achieve the control way of multicomponent and multilevel 3D micro/nano structure. Besides, the effects of the 3D micro/nano structure and mechanical strength of composite adsorptive material on the adsorption/desorption property towards pollutant in water, regeneration capacity and other properties of composite adsorptive material were further explored. Finally, the single and multiple adsorption/desorption rules of composite adsorptive material towards heavy metal ion, dye and organic compound were investigated. The adsorption thermodynamics and kinetics model were established, and the synergetic mechanism was also revealed. These study results are favor for improving the basic research level of adsorptive material in our country, and providing a new idea and a theoretical model to develop a new type of high-performance 3D composite adsorptive material.

三维石墨烯类及其复合吸附材料除兼具本身优异理化特性外，还显示吸附量大、亲/疏水性易调控、可重复使用等优点，但现有研究大都只针对单元污染物，且在吸附机制方面研究不系统。因此，本项目先通过液相或固相法制备石墨烯类物质，然后在水中与铁和亚铁化合物、壳聚糖或其衍生物等分散均匀并制成水凝胶，再经过冷冻干燥等后处理构建了三维微纳磁性壳聚糖/石墨烯类复合吸附材料。系统研究原料组成结构、制备工艺条件对复合吸附材料组成结构的影响规律，获得其多组分多层次三维微纳结构的调控方法；进一步研究复合吸附材料三维微纳结构与其机械强度，对水中污染物吸附、脱附和再生性能，以及其它性能之间的内在关系；深入研究水中重金属离子、染料、有机物在复合吸附材料上的单多元吸附与脱附规律，建立吸附热力学与动力学模型，揭示其协同增效机制。该研究有利于提高我国吸附材料基础研究水平，并为发展一类新型高效三维复合吸附材料提供思路和理论模型。

目前三维石墨烯类吸附材料的研究大都只针对单一污染物，且对吸附机制研究不系统。本项目以二维结构的石墨烯类材料为基体制备多类新型吸附或多功能材料。通过研究，获得以下一些重要研究结果：（1）制备含4%蒙脱土的石墨烯基复合气凝胶，显示优异压缩性和选择吸附性，对MB和Cr(VI)的最大吸附容量分别为227.27、77.52 mg.g-1，其吸附过程属化学吸附、且都符合Langmuir吸附等温模型和准二级动力学模型，经4次再生循环后对MB和Cr(VI)去除率均超过94%，并显示良好抗菌性；（2）采用冻融物理交联法制备石墨烯基复合水凝胶，发现其对废水中Cd2+和Ni2+最大吸附容量分别为172.11和70.37 mg.g-1，符合Langmuir等温模型和二级动力学模型，优化的GCP1:2:4水凝胶经6次再生循环后对两种离子吸附效率均超过80%，同时水中Ni2+或Cd2+存在对GCP1:2:4水凝胶吸附Cd2+或Ni2+分别有协同性和竞争性；（3）分别制备质量比 6:1的石墨烯和氧化钼复合气凝胶、含Cu2O/g-C3N4异质结（Cu2O质量分数40%）的石墨烯基复合水凝胶40-NOG，对水中MB和MO显示良好降解性，且经过几次循环再生后其降解效率下降不大；（4）分别制备木棉纤维-石墨烯、魔芋葡甘聚糖-石墨烯、硅氧烷超疏水改性魔芋葡甘聚糖-石墨烯三类气凝胶，对油品和有机溶剂均显示优异吸附性和再生循环性，超疏水改性气凝胶的水接触角高达150.3°；（5）制备的多孔少层石墨对水中全氟辛基磺酸钾最大吸附容量高达2.48 mmol. g−1 ，通过热处理5次再生循环后吸附性能下降很小。（6）氧化石墨烯接枝天然聚合物如海藻酸钠等载体，显示良好药物吸附性和pH敏感控释性，构建的抗癌释药系统显示良好生物和血液相容性及明显结肠靶向抗癌效果。（7）制备的负载溴化十六烷基吡啶的蒙脱土-氧化石墨烯复合物，对水中细菌显示良好吸附性和杀灭性，且毒性很小。通过研究，发表SCI及EI收录论文18篇，获广东省优秀科技成果奖1项，获授权发明专利1件，培养博士生1名、硕士生7名。该成果有利于发展新型高性能和多功能吸附材料，并推动化学、化工、材料、环境和生物医学等学科及相关产业发展。