【作者】 王娟娟；

【导师】 王永洪；

【作者基本信息】 太原理工大学 ， 化学工程与技术， 2021， 硕士

【摘要】 混合基质膜以聚合物基体为连续相,无机颗粒为分散相,结合了聚合物膜和无机膜的优点具有优异的气体分离性能。与传统的混合基质膜相比,含载体的复合膜由混合基质薄膜和多孔载体组成,这种类型的膜由于其超薄的选择性层并且对铸膜液含量要求较低等特点在气体分离领域受到科研工作者的青睐,但其经常受到填料与聚合物基质间相容性差等问题的限制。为了解决这一问题,本文以聚乙烯胺为高分子基质,分别采用氨基化Cu₃（BTC）₂插层蒙脱土、聚苯胺改性酸活化蒙脱土、聚乙烯亚胺修饰多孔蒙脱土为无机填料,构建具有高效促进传递通道的混合基质复合膜,用于CO₂/N₂分离体系。具体研究内容如下:（1）本章通过Cu²⁺与蒙脱土（MMT）层间Na⁺进行阳离子交换,然后,经过均苯三甲酸与Cu²⁺的配位络和作用在MMT层间原位生成Cu₃（BTC）₂,制备具有插层结构的杂化材料;再利用3-氨基丙基三乙氧基硅烷（KH550）对MMT表面修饰,在MMT层间引入具有促进传递作用的载体。将胺基改性的Cu₃（BTC）₂-MMT复合材料添加到PVAm基质中作为选择性涂层涂覆到聚砜（PSf）支撑体上,制备了PVAm/Cu₃（BTC）₂-MMT-NH₂MMCMs。通过XRD和FTIR证实了Cu₃（BTC）₂进入MMT层间,与此同时也证实了KH550改性成功。Cu₃（BTC）₂-MMT-NH₂复合材料的层间空间为CO₂的传递构建了快速促进传递通道。当Cu₃（BTC）₂-MMT-NH₂添加量为3 wt%时,其CO₂渗透速率为203 GPU,CO₂/N₂选择性为100.7,且在360 h测试期间内性能保持稳定,混合基质复合膜的性能远远超过2008年的Robeson上限。（2）本章采用盐酸活化MMT,使得H⁺与MMT层间Na⁺交换形成孔道,同时八面体中的Al–OH基团被质子化,导致Al³⁺的溶解,溶解后使其孔道增加。基于阳离子交换和原位聚合工艺在酸活化蒙脱土纳米片的表面和层间成功合成聚苯胺纳米颗粒,制备了聚苯胺改性酸活化蒙脱土纳米片复合材料（PANI-a/MMT）。将PANI-a/MMT添加到PVAm基质中成功制备了PVAm/PANI-a/MMT MMCMs。通过XRD和FTIR证实了酸活化MMT结构的变化以及PANI在层间的成功合成。PANI-a/MMT结合了PANI大量的仲胺基团和酸活化蒙脱土纳米片大的比表面积和孔结构构建CO₂直的气体传递通道,提高了CO₂渗透性和CO₂/N₂选择性。当PANI-a/MMT添加量为1 wt%时,PAVm/PANI-a/MMT MMCMs的CO₂渗透速率为254 GPU,CO₂/N₂选择性为87.3,且在360 h测试期间内性能保持稳定并超过2008年的Robeson上限。（3）本章通过NaOH与MMT的固相反应脱硅产生微孔,制备了多孔MMT（p-MMT）,采用聚乙烯亚胺（PEI）与p-MMT刻蚀孔周围的Si–O^–静电化学作用,调控p-MMT的孔化学结构,构建互连二维多孔结构PEI修饰的p-MMT（P@p-MMT）复合材料,将P@p-MMT添加到PVAm基质中制备了具有连续促进传递通道的PVAm/P@p-MMT MMCMs。通过无机材料的SEM证实了多孔结构的产生,FTIR和XRD证实了NaOH刻蚀前后MMT结构的变化,TG证实了PEI在p-MMT多孔结构中的存在和近似浓度,经过氮气吸脱附实验、孔径分布验证了p-MMT和P@p-MMT的孔结构特征。通过对混合基质复合膜的ATR-FTIR和断面的SEM进行了表征,可知P@p-MMT在PVAm基质中分散良好且与PVAm基质间具有较强的相互作用。P@p-MMT连续的促进传递通道增加了气体传递路径,强化膜分离过程。当P_3.2@p-MMT2添加量为2 wt%时,PVAm/P_3.2@p-MMT2 MMCMs表现出优异的气体分离性能,CO₂渗透速率达217 GPU,CO₂/N₂选择性为112.3,超过了2008年的Robeson上限。更多还原

【Abstract】 Mixed matrix membrane takes polymer matrix as continuous phase and inorganic particles as dispersed phase,which combines the advantages of polymer membrane and inorganic membrane and has excellent gas separation performance.Compared with the traditional mixed matrix membrane,the composite membrane with carrier is composed of mixed matrix films and porous support.This type of membrane is favored by researchers in the field of gas separation because of its ultra-thin selective layer and low requirement for casting solution content,but it is often limited by poor compatibility between filler and polymer matrix.To solve this problem,in this paper,polyvinylamine was used as polymer matrix,and aminated Cu₃（BTC）₂ intercalated montmorillonite,polyaniline modified acid activated montmorillonite and polyethyleneimine modified porous montmorillonite were used as inorganic fillers,respectively,to construct a mixed matrix composite membrane with high-efficiency transmission channels for CO₂/N₂ separation system.The main research contents are as follows:（1）Cu²⁺is exchanged with Na⁺between MMT layers,and then Cu₃（BTC）₂ was generated in situ between MMT layers by coordination and action of trimellitic acid and Cu²⁺,thus preparing hybrid materials with intercalation structure.Then,3-aminopropyltriethoxy-silane（KH550）was used to modify the surface of MMT,and a carrier with the function of facilitating transport was introduced between MMT layers.The amino-modified Cu₃（BTC）₂-MMT composite was added to PVAm matrix as a selective coating and coated on PSf support to prepare PVAm/Cu₃（BTC）₂-MMT-NH₂ MMCMs.XRD and FTIR confirmed that Cu₃（BTC）₂ entered MMT interlayer,which also confirmed that KH550 was successfully modified.A fast lamellar transmission channel of Cu₃（BTC）₂-MMT-NH₂ was contructed for CO₂ transport.When the loading of Cu₃(BTC2)-MMT-NH₂ is 3 wt%,the CO₂ permeance is203 GPU,and the CO₂/N₂ selectivity is 100.7.And the MMCMs exhibited excellent long-term stability performance during 360 h test,far surpassing the Robeson’s upper bound proposed in 2008.（2）The MMT was activated by hydrochloric acid,so that H⁺exchanged with Na⁺between MMT layers to form channels,and the Al–OH group in octahedron was protonated,which led to the dissolution of Al³⁺,and the channels increased after dissolution.Polyaniline nanoparticles were successfully synthesized on the surface and interlayer of acid-activated montmorillonite nanosheets based on cation exchange and in-situ polymerization,and PANI-a/MMT composites were prepared.PANI-a/MMT was added to PVAm matrix to successfully prepare PVAm/PANI-a/MMT MMCMs.XRD and FTIR confirmed the structural change of acid activated MMT and the successful synthesis of PANI between layers.PANI-a/MMT combines a large number of secondary amine groups of PANI and large specific surface area and pore structure of acid-activated montmorillonite nanosheets to construct a straight CO₂ transmission channel,which improves CO₂ permeance and CO₂/N₂selectivity.When the loading of PANI-a/MMT is 1 wt%,PVAm/PANI-a/MMT MMCMs has a CO₂ permeance of 254 GPU and a CO₂/N₂ selectivity of 87.3.And the MMCMs exhibited excellent long-term stability performance during 360 h test,far surpassing the Robeson’s upper bound proposed in 2008.（3）Porous MMT（p-MMT）was prepared by solid-state reaction of NaOH and MMT to produce micropores via desilication.PEI-modified p-MMT（P@p-MMT）composites with interconnected two-dimensional porous structure were constructed by using the electrostatic chemical interaction of polyethyleneimine（PEI）and Si–O^–around p-MMT etching holes.PVAm/P@p-MMT with continuous facilitated transport channels was prepared by adding P@p-MMT into PVAm matrix.SEM of inorganic materials confirmed the generation of porous structure,FTIR and XRD confirmed the change of MMT structure before and after NaOH etching,TG confirmed the existence and approximate concentration of PEI in p-MMT porous structure,and nitrogen adsorption and desorption experiments and pore size distribution verified the pore structure characteristics of p-MMT and P@p-MMT.The ATR-FTIR and SEM of the cross-section of mixed matrix composite membranes were characterized.It can be seen that P@p-MMT is well dispersed in PVAm matrix and has strong interaction with PVAm matrix.P@p-MMT continuously facilitates transport channels to increase the gas transport passway and strengthen the membrane separation process.When the loading of P_3.2@p-MMT2 is 2 wt%,the PVAm/P_3.2@p-MMT2 MMCMs exhibits an excellent gas separation performance with CO₂ permeance of 217 GPU and CO₂/N₂selectivity of 112.3,which surpassed the 2008 Robeson upper-bound.更多还原