多级孔MOFs材料合成及对苯系物VOCs的吸附性能研究

Benzenes in the environment do harm to human health and destroy the ecological environment to a great extent, while porous materials are the most commonly used adsorbents which can remove benzenes in medium-low concentrations effectively. As a new kind of porous crystal materials, metal-organic frameworks have a great advantage in gas adsorption over other traditional materials like activated carbon and zeolites due to their excellent features such as large surface areas, tunable pore sizes, and diverse structures. While most MOFs are microporous materials, which limit the diffusion rate of molecules such as benzenes in the pores and have influence on adsorption capacities. Recently, hierarchical-pore MOFs materials consisting of microporous, mesoporous and macroporous which have faster diffusion rates and higher adsorption capacities have been investigated extensively. However, the research on synthesis of stable high-quality hierarchical-pore MOFs with good adsorption performance towards benzenes, especially their diffusion behavior in hierarchical pores and adsorportion mechanisms is an emerging field. In this project, we will synthesize hierarchical-pore MOFs in situ, investigate the adsorption/desorption performance of benzenes on the materials, establish structure-performance relationship and finally discuss the adsorption mechanism.The study above may cast a light on the adsorption removal of VOCs in the environment.

环境中的苯系物严重危害人体健康和破坏生态环境，多孔材料是常用的有效去除中、低浓度苯系物的吸附剂。金属有机骨架材料（MOFs）作为一种新型多孔材料，巨大的比表面积、可调的孔尺寸、多样的骨架结构等使其与活性炭、分子筛等传统吸附材料相比在气体吸附领域具有很大优势。然而，大多数MOFs属于微孔材料，限制了苯系物等分子在孔道内的扩散与传质速率，进而影响吸附容量。近年来，由微孔、介孔及大孔组成的多级孔MOFs材料由于具有较快的气体传质速率和较高的气体吸附容量而被广泛关注。而稳定、高质量多级孔MOFs材料的合成及对苯系物等分子吸附性能的研究作为一个新兴方向，苯系物在多级孔MOF材料复杂孔道内的扩散行为及吸附规律等关键科学问题依然悬而未决。本项目通过合成多级孔MOFs材料，研究其对苯系物的吸附/脱附性能，建立结构-性能的构效关系，探讨吸附机理，为环境中苯系物VOCs的吸附治理研究奠定理论基础。

苯系物VOCs是强致癌和难降解物质，在其生产、储运、使用过程中均会由于挥发而造成环境污染，从而危及人体健康。吸附技术是处理苯系物VOCs的有效技术之一，而目前传统的吸附剂如活性炭、分子筛等由于比表面积较小限制了对苯系物的吸附容量。因此，开发新型高效的苯系物吸附材料至关重要。本项目开展了金属有机骨架材料（MOFs）的合成实验，确定了MOFs材料合成的最佳反应条件，实现温和条件下制备高质量MOFs材料。开发的MOFs材料比表面积最高可达3120m2/g，是活性炭等材料的2.5-6.3倍。研究了MOFs材料对苯的吸附-脱附性能。开发的MOFs材料对苯的吸附容量最高可达1290 mg/g，是活性炭等传统吸附材料的2-4倍；同时对苯具有更低的吸附/脱附活化能、更快的吸附/脱附速率，具有较好的再生性能。本项目研发的新型MOFs材料具有优良的苯系物吸脱附效果，为MOFs材料用于环境中苯吸附回收治理应用奠定了基础。