用于油水分离和碘吸附的枫香果壳@COFs的制备

Preparation of@COFs from maple fruit shells for oil-water separation and iodine adsorption

石油工业发展产生的大量含油废水、核能发展产生的放射性碘排放均对人类健康与环境构成威胁,制备多功能吸附材料有效进行油水分离、碘吸附已成为近年来的热点研究。枫香是中国优良速生树种,枫香果具有天然的多孔结构,但每年有大量的枫香果作为农林废弃物而得不到合理利用。本研究以枫香果壳作为基底材料,在脱木素预处理的基础上通过(3-氨基丙基)三乙氧基硅烷将枫香果壳氨基化,并利用席夫碱反应将共价有机框架(COFs)接枝在枫香果壳表面,生成枫香果壳@COFs复合材料。通过N_(2)吸附-脱附实验、有机溶剂吸附实验、碘吸附实验对复合材料的性能进行表征。实验结果表明:该复合材料拥有良好的油水分离能力和碘吸附性能。复合材料的比表面积为190 m^(2)/g,在13种有机溶剂中表现出良好的吸附能力以及循环性能,对三氯甲烷的吸附容量最大可达5841 mg/g,并在20次循环后保持90%的吸附容量。此外,在碘蒸气中的吸附容量达到1180 mg/g,并在5次循环后仍保持50%以上的吸附容量。该复合材料不仅成本低、天然环保,还具有优异的可回收性能以及循环性。研究结果有望为此类农林废弃物提供新的利用思路,也为废水处理提供新的方案。

A large amount of oily wastewater produced by the development of the petroleum industry and radioactive iodine discharge from the development of nuclear energy poses a threat to human health and the environment.The treatment of oily wastewater and adsorption of iodine are imminent and have become the focus of attention in the world.In recent years,the preparation of multifunctional adsorption materials for effective separation of oil and water and iodine adsorption has been a hot topic.Covalent organic framework(COFs)has advantages of large specific surface area and good adsorption effect,but its powdery structure is difficult to recover and usually causes secondary pollution to the water body.Amblygum(Liquidambar formosana Hance)is an excellent fast-growing tree in China.Its fruit has a natural porous structure and a large amount of amblygum is used for the treatments of agricultural and forestry waste every year.The dried and mature fruit consists of a large number of small capsules,spherical in shape,2-3 cm in diameter.The highly lignified shell forms a bark-shaped frame,with excellent mechanical properties,high porosity,and large specific surface area.Therefore,it can be used as a good carrier for COFs grafting.In this study,on the basis of the takeoff lignin pretreatment by amino propyl(3-)triethoxy silane,maple fruit shells were utilized as a basal material for maple fruit shell amination and the Schiff base reaction was used to covalent organic framework(COFs)grafted on the surface maple fruit shell,generating maple fruit shell@COFs composite materials.The properties of the developed composite were characterized by N_(2)adsorption-desorption experiment,organic solvent adsorption experiment and iodine adsorption experiment.The experimental results showed that the composite material maintained the original spherical and pore structure and had good oil-water separation ability and iodine adsorption performance.The specific surface area of the composite was 190 m^(2)/g,showing good adsorption capacity and cycling performance in 13 organic solvents,among which the adsorption capacity of trichloromethane can reach up to 5841 mg/g,and the adsorption capacity still maintained 90%after 20 cycles.In addition,the adsorption capacity in iodine vapor reached 1180 mg/g and remained above 50%after five cycles.The composite material not only has advantages of low cost,natural environmental protection,but also has excellent recyclability and recyclability.In this study,a simple scheme for preparing@COFs of maple fruit hulls was proposed,which is expected to provide a new utilization idea for this kind of agricultural and forestry waste and a new scheme for wastewater treatment.