Abstract:

In view of the low surface porosity of 2D MoS₂ nanosheets, the long interlayer stacking mass transfer path and the poor compatibility in polymers, it is difficult to simultaneously improve the selectivity and permeance of their mixed matrix membrane. In this paper, vacancy- and defect-rich MoS₂ (P- MoS₂) was first prepared by ion imprinting technology, and 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole (AHMT) was used to modify P- MoS₂ to prepare hybrid materials (AHMT- MoS₂). Then, AHMT-MoS₂ was added to polyether block polyamide (Pebax) to prepare cast film solution and then coated on polysulfone (mPSf) support to prepare mixed matrix composite membranes (Pebax/AHMT-MoS₂). Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM) and N₂ adsorption and desorption were used to characterize the chemical, morphological and pore structures of the materials and membranes. The effects of the preparation and testing conditions of the materials on gas separation were investigated. The results showed that Pebax/AHMT-MoS₂ exhibited CO₂ permeance of 818 GPU and CO₂/N₂ selectivity of 56. This was attributed to the construction of the defects on the surface of MoS₂ by ion imprinting strategy, which increased the CO₂ affinity; its surface pores could provide diffusion channels for CO₂. In addition, introduction of amino and hydrazine groups enhances the reaction selectivity of CO₂ and significantly improves the separation. Due to excellent gas separation performance and low cost, it makes as-prepared mixed matrix composite membranes highly potential for the application in CO₂ separation.

Key words: membranes, separation, carbon dioxide capture, MoS₂ modification, ion imprinting strategy

摘要：

由于二维MoS₂纳米片表面孔隙率低、层间堆积传质路径长以及在聚合物中相容性差等问题，很难同时提高其混合基质膜的选择性和渗透速率。本工作首先通过离子印迹技术制备得富含空位和缺陷的MoS₂（P-MoS₂），并使用4-氨基-3-肼基-5-巯基-1,2,4-三唑（AHMT）对P-MoS₂改性制备杂化材料（AHMT-MoS₂）。然后将AHMT-MoS₂添加到聚醚嵌段聚酰胺（Pebax）中制备铸膜液，并涂覆在亲水改性的聚砜（mPSf）支撑体上制备混合基质复合膜（Pebax/AHMT-MoS₂）。采用傅里叶变换红外光谱（FTIR）、X-射线衍射（XRD）、扫描电镜（SEM）和N₂吸附-脱附表征材料和膜的化学结构、孔隙结构和形态结构。研究了材料的制备条件和测试条件对气体分离的影响。结果表明，Pebax/AHMT-MoS₂的CO₂渗透速率为818 GPU，CO₂/N₂选择性为56。这是因为通过离子印迹策略在MoS₂表面构建缺陷，增加了CO₂亲和位点；其表面孔和层间通道为CO₂提供了扩散通道。同时，氨基和肼基的引入，增强了CO₂的反应选择性，显著提高分离效果。优异的气体分离性能与低成本，使制备的混合基质复合膜在CO₂分离领域极具应用潜力。

关键词: 膜, 分离, 二氧化碳捕集, MoS₂改性, 离子印迹策略