Factors Controlling Successful Formation of Mixed-Matrix Gas Separation Materials

Abstract

Prior work has suggested simple guidelines for matching transport characteristics of materials to form high-performance mixed-matrix materials for gas separation. Such materials comprise a dispersion of molecular sieving particles in a properly selected matrix polymer phase. Recent work has shown that these simple criteria are necessary but not sufficient to achieve the desired properties. The analysis presented here shows the need to optimize the transport properties of the interfacial region, i.e., the region between the bulk polymer and dispersed sieve phases. Guided by the need to optimize both the transport properties of the interfacial region and the matrix material selection criteria noted above, a new paradigm is recommended for matrix phase selection. The practicality of the paradigm is validated by the formation of mixed-matrix membranes with an appropriate polymer and sieve. These materials lead to the attractive predicted performances at low loading. For success at higher loading a zeolite "priming" protocol based on polymer-solvent sieve interactions is shown to be necessary. This modified protocol leads to success at intermediate and high dispersed-phase loading.

Selective, Room-Temperature Transformation of Methane to C1 Oxygenates by Deep UV Photolysis over Zeolites

“…In all cases, the selectivity is much higher than that of the pure PTMSP membranes tested in the laboratory and that of the commercial membrane Pervap 4060 (Sulzer Chemtech, Alschwill, Switzerland) used for comparison purposes. Thus, the molecular sieving effect of the small-pore zeolites to the polymer matrix and the absence of defects due to good compatibility between the fillers and the polymer matrix [20,21] contributes to overcoming the separation performance of other MMMs reported in the literature [9][10][11]31]. The influence of temperature in the O2/N2 gas separation performance of these MMMs has been analyzed in terms of gas permeability and gas diffusivity in the range from 298 to 333 K. The O2 The influence of temperature in the O 2 /N 2 gas separation performance of these MMMs has been analyzed in terms of gas permeability and gas diffusivity in the range from 298 to 333 K. The O 2 permeability values as well as the O 2 /N 2 selectivities of the different MMMs studied in this work are collected in Table 1, as well as those of other MMMs reported in the literature.…”

Zeolite membranes – a review and comparison with MOFs

“…99 Mixed matrix membranes combining polymers with zeolites have long been studied extensively aiming at low-cost, highperformance membranes. [100][101][102][103][104][105][106][107][108] (see also Section 13). However, the inherent incompatibility between zeolites and polymers still remains a limitation, while performance of these membranes has remained low to modest at best.…”

Metal–Organic Framework-Functionalized Alumina Membranes for Vacuum Membrane Distillation

“…These membranes exploit the advantages of the unique molecular sieve characteristics of MOF and the good processability of polymers. However, mixed matrix membranes often have defective morphology due to the voids between polymer chains and nano-particles [15][16][17]. One approach to address this issue is to prepare a continuous MOF layer on top of the supports.…”