Vapor/gas separation through carbon molecular sieve membranes: Experimental and theoretical investigation

Preparation and Characterization of Free-Standing Composite Cellulose-Based Carbon Molecular Sieve Membranes

“…values of 46° [43]. In Figure 4B, these peaks are practically imperceptible, which allows us to conclude that the boehmite and γ-Al 2 O 3 nanoparticles are well dispersed in the carbon matrix and did not undergo crystallization [26]. This is also because the boehmite concentration is quite small, and the equipment is not sensitive enough to detect these planes.…”

“…Gas and water vapor permeability increases up to a boehmite concentration of 0.8 wt. % [26]. Similarly, the selectivity of water vapor to other gases increases with the alumina content.…”

“…This happens because boehmite nanoparticles reduce the carbon matrix shrinkage during the carbonization process. According to some authors, boehmite nanoparticles suffer dehydration during carbonization and form a well-dispersed Al 2 O 3 nanofiller in the carbon matrix, with preferential axial orientation, thus hindering the excessive shrinkage of the membrane [20,24,26]. As shown in Figure 1, freestanding c-CMSM prepared at 550 °C, with a thickness of ca.…”

“…The authors found that, during the carbonization step, boehmite partially decomposed into γ-Al 2 O 3 nanosheets, increasing the membrane hydrophilicity and consequently improving water vapor permeation up to a boehmite concentration of 1 wt. % [26]. Furthermore, they found that γ-Al 2 O 3 nanosheets do not affect the pore size distribution of the membranes in the region of the micropores (0.6 < d < 2 nm) but introduce more defects into the carbon matrix, increasing its tortuosity and/or porosity.…”

“…More recently, Poto et al [26], prepared several phenolic resin precursor solutions with different concentrations of boehmite. Due to its hydrophilicity, boehmite was used to increase water adsorption into the porous carbon matrix.…”