智能光响应金属有机骨架材料的构筑及苯/环己烷吸附分离性能研究

Benzene and cyclohexane are important industrial chemicals. However, owing to the similarities between both dynamic diameters and boiling points, the efficient separation is achieved by adopting azeotropic distillation and extractive distillation in the industry, and the separation process has the problems of high energy consumption and solvent pollution. The adsorptive separation is a promising separating technology of mixtures due to its simple operation and low energy consumption. Choosing appropriate adsorbents is the core of achieving efficient adsorptive separation process. Unfortunately, traditional adsorbents with fixed pore structures are unlikely to realize the both of selectivity in the adsorption process and facilitate desorption in the regeneration process. Despite great challenges, it is extremely desirable to develop a new type of adsorbent possessing pore structures and surface properties that are adjustable during adsorption/desorption. This project intends to develop a new type of adsorbent possessing pore structures and surface properties that are adjustable during adsorption/desorption by employing spiropyran derivatives to construct photo-responsive molecular switches in MOFs. Based on the differences between the nature of benzene and cyclohexane, optimization design of the smart photo-responsive adsorbents is adopted for the separation of the mixture compounds. Selective adsorption and efficient regeneration can be both realized in different irradiation conditions. The project aims to form preparation theories of photo-responsive adsorbents. Combined with various characterization test methods, the photo-regulating mechanisms of pore structures and surface properties are clarified, which affects the adsorptive separation process of benzene/cyclohexane mixtures and regeneration performance. It is prospective to provide a portion of theoretical basises to achieve energy saving and efficient adsorption separation process.

苯和环己烷均为重要的化工原料，但其动力学直径和沸点均相近，工业上多采用共沸精馏或萃取精馏实现两者的高效分离，分离过程存在耗能高和溶剂污染等问题。吸附分离技术因操作简单且能耗低，在混合物分离方面具有广阔应用前景，选择合适的吸附剂是实现高效吸附分离过程的核心。传统吸附剂孔结构及性质不可调变，难以同时实现选择性吸附和高效再生。项目拟采用螺吡喃类衍生物在金属有机骨架材料骨架中构筑光响应“分子开关”，优化设计适用于苯/环己烷体系的智能光响应吸附剂。通过光照调控材料孔道结构及表面性质，基于苯与环己烷分子表面电荷、极性的差异，在不同条件下实现选择性吸附和低能耗再生。通过本项目的研究，形成光响应吸附剂的制备理论，结合多种表征测试方法对材料的微观结构和理化性质进行分析，阐明吸附剂孔结构及表面性质的光控调变机理，研究其对苯/环己烷体系的吸附分离效果和再生性能，为实现高效、节能的吸附分离过程提供一定的理论基础。

吸附分离技术因具有设备投入成本较低，操作简单以及能源利用率高等优势而被广泛应用于化工生产过程中，而选择合适的吸附剂是实现高效吸附分离过程的核心。理想的吸附剂既要求在吸附过程中拥有较小的孔径从而实现选择性吸附，又要求在脱附过程中拥有较大的孔径从而实现高效再生。传统吸附剂由于孔结构及孔道表面性质不可调变，往往难以同时满足上述要求。本项目针对这一不足，以介孔二氧化硅和金属有机骨架材料为载体，采用偶氮苯、香豆素和螺吡喃等光响应分子进行功能化修饰，将载体优异的孔结构和吸附性能与光响应分子独特的光致异构性能相结合，成功制备了一系列新型智能光响应吸附剂。该材料能够通过外界的光照刺激，实现吸附剂自身孔径或表面性质的调变，从而在吸附/脱附过程中分别以不同的性质满足不同的要求，实现选择性吸附/高效再生。研究过程中，结合多种表征测试方法分析了材料的微观结构和理化性质，阐明了吸附剂孔结构及表面性质的光控调变机理，在苯/环己烷吸附分离、二氧化碳吸附、燃料油脱硫和染料废水处理等方面均取得了良好的应用效果，为实现高效、节能的吸附分离过程提供新的思路和一定的理论基础。