含有氢键供/受体的MOFs材料对生物基多元醇吸附分离的研究

The synthesis of bio-based polyols is one of the important development directions of green biological manufacturing. The concentration of polyols obtained from biorefining system is very low, resulting in the urgent demand of the separation technology with high-efficiency and low-energy consumption. In this project, aiming at the requirement of high-efficiency separation of biomass-derived polyols, we intend to study the adsorption properties of metal-organic frameworks (MOFs) for separation of polyols, taking full advantage of the application-oriented design, controllable synthesis and functional modification of MOF materials. In order to improve the low adsorption capacity and poor selectivity, the experiments in the following sections are based primarily on the following two core ideas: selective hydrogen bonding and molecular sieve effect. In particular, MOFs with selective adsorption site for polyols are prepared by introducing the hydrogen-bonding donors/acceptors that can form hydrogen bonds with hydroxyl groups of polyols into the skeleton of MOFs. The aperture and pore sizes of MOFs are fine adjusted as well. Then the static and dynamic adsorption characteristics of polyols on the obtained MOF adsorbents are studied. In addition, we will investigate the effects of the types and positions of hydrogen-bonding donors/acceptors, and aperture/pore sizes of MOFs on the polyol adsorption performance. Through this study, the MOF adsorbents with high adsorption capacity and excellent selectivity for separation of bio-based polyols can be obtained. In addition, the obtained scientific understanding of structure-performance relationship will provide important instruction to the application of MOFs in other fields.

生物基多元醇是绿色生物制造的重点发展方向之一。生物炼制制备的多元醇浓度低，其高效低能耗分离技术亟需突破。本项目以生物基多元醇的高效分离为目的，优选吸附分离技术，针对多元醇吸附容量低和吸附选择性差两个重要问题，充分利用金属-有机骨架（MOFs）材料易于定向设计、可控合成和功能化修饰的特点，提出了选择性氢键作用和分子筛分作用的研究思路，开展MOFs材料针对多元醇选择性富集分离的研究：1）MOFs基吸附剂上氢键吸附位点的构建、孔/笼尺寸调节；2）MOFs对多元醇的静态及动态吸附特性研究；3）MOFs的多元醇吸附性质与其骨架中氢键供/受体的类型和位置、孔/笼尺寸的关联研究。通过本项目的研究，一方面，可以获得面向多元醇分离用的兼具吸附容量和选择性的高性能MOFs吸附材料，另一方面，构效关系研究有望为MOFs材料在其它分离领域的应用提供重要借鉴。

生物基多元醇是绿色生物制造的重点发展方向之一。生物炼制制备的多元醇浓度低，其高效低能耗分离技术亟需突破。本项目充分利用金属-有机骨架（MOFs）材料易于定向设计、可控合成和功能化修饰的特点，提出了选择性氢键作用和分子筛分作用的研究思路，开展MOFs材料针对多元醇选择性富集分离的研究。依据亲水性差异、孔径差异、氢键供/受体的差异等考察因素，本项目主要研究的MOF材料为具有优异稳定性的ZIFs材料（如ZIF-8、ZIF-90、ZIF-93、ZIF-94、ZIF-97等）和含铝MOF材料（CAU-10-H和MIL-53）。分离对象主要为单元醇（如乙醇和异丁醇）和多元醇（如乙二醇、1,3-丙二醇、丙三醇、丁二醇等）。本项目系统研究了ZIFs材料和含铝MOF上多种醇类的吸附行为。研究表明ZIFs材料中含有醛基官能团且孔径在3Å左右的ZIF-94展现出最为优异的多元醇吸附性能，且1,3-丙二醇/丙三醇吸附选择性达到86。开发了高性能的MOF膜，系统考察了其对乙醇/水体系和异丁醇/水体系的渗透汽化分离性能。Zn2(bim)4/PMPS混合基质膜的异丁醇/水选择性为42，在连续半个月的测试中渗透汽化性能未见衰减。CAU-10-H膜对于酸性体系下的乙醇水溶液分离（pH~2），展现出优异的分离性能和性能稳定性。项目执行过程中已发表论文9篇，申请专利2项（已授权1项），已培养硕士生4名。