Bünger Lucas, Kurtz Tim, Garbev Krassimir, Stemmermann Peter, Stapf Dieter
Institute for Technical Chemistry, Karlsruhe Institute of Technology, Kaiserstrasse 12, 76131 Karlsruhe, Germany.
Membranes (Basel). 2024 Jul 12;14(7):156. doi: 10.3390/membranes14070156.
This study introduces an innovative approach to designing membranes capable of separating CO from industrial gas streams at higher temperatures. The novel membrane design seeks to leverage a well-researched, high-temperature CO adsorbent, hydrotalcite, by transforming it into a membrane. This was achieved by combining it with an amorphous organo-silica-based matrix, extending the polymer-based mixed-matrix membrane concept to inorganic compounds. Following the membrane material preparation and investigation of the individual membrane in Part 1 of this study, we examine its permeation and selectivity here. The pure 200 nm thick hydrotalcite membrane exhibits Knudsen behavior due to large intercrystalline pores. In contrast, the organo-silica membrane demonstrates an ideal selectivity of 13.5 and permeance for CO of 1.3 × 10 mol m s Pa at 25 °C, and at 150 °C, the selectivity is reduced to 4.3. Combining both components results in a hybrid microstructure, featuring selective surface diffusion in the microporous regions and unselective Knudsen diffusion in the mesoporous regions. Further attempts to bridge both components to form a purely microporous microstructure are outlined.
本研究介绍了一种创新方法，用于设计能够在更高温度下从工业气流中分离一氧化碳（CO）的膜。这种新型膜设计旨在利用一种经过充分研究的高温CO吸附剂——水滑石，将其转化为膜。这是通过将它与一种非晶态有机硅基基质相结合来实现的，从而将基于聚合物的混合基质膜概念扩展到无机化合物。在本研究第1部分完成膜材料制备并对单个膜进行研究之后，我们在此考察其渗透性和选择性。由于晶间孔隙较大，纯的200纳米厚水滑石膜表现出克努森行为。相比之下，有机硅膜在25℃时对CO的理想选择性为13.5，渗透通量为1.3×10⁻⁷mol m⁻² s⁻¹ Pa⁻¹，而在150℃时，选择性降至4.3。将两种组分结合会产生一种混合微观结构，其在微孔区域具有选择性表面扩散，在介孔区域具有非选择性克努森扩散。文中还概述了进一步尝试将两种组分连接起来以形成纯微孔微观结构的情况。
