This website presents charts depicting the highest reported gas separation performances across various membrane technologies, covering data published from 2000 to the present. Charts of gas separation performances for individual gas pairs can be accessed through the links provided below.
Membrane Chart Explanatory Notes
The membranes presented in these state-of-the-art charts represent separation performances reported in the scientific literature. In these charts, the performances are expressed using Robeson indices, as described below. The data are organized according to different membrane material types and permeation mechanisms.
The Robeson Index is, for a given permeability, the ratio between the actual selectivity value and the one corresponding to the Robeson upper bound (α(i,j│RUB)):
where Li is the permeability of the fastest gas, and α(i,j) is the ideal selectivity, m is the slope of the Robeson Upper Bound for the actual gas pair, and it is equal to the slope of the log-log of the relationship, and β is the y-intercept of the Robeson upper bound. The major advantage of the Robeson index is that it qualifies the membrane performance as a single number, enabling the construction of performance history charts.
The Figure 1 below exemplifies the concept of Robeson Index θ for the O2/N2 separation. This Figure represents, in a Robeson plot, the θ values for selected membranes from the literature. The line with θ = 1 corresponds to the Robeson upper bound line for the O2/N2 separation, as published in 2008 [1].
Membrane Permeability Measurements
Our laboratory provides specialized testing services for assessing the gas permeability of a wide range of membrane materials. To learn more about our testing procedures or to request a permeability analysis for your membranes, please follow the following link: Membrane Permeability Measurements
References
[1] Robeson, L.M., The upper bound revisited. Journal of Membrane Science, 2008. 320(1): p. 390-400[2] Sun, L., et al., In-Situ Formation of Three-Dimensional Network Intrinsic Microporous Ladder Polymer Membranes with Ultra-High Gas Separation Performance and Anti-Trade-Off Effect. Angewandte Chemie International Edition, 2025. 64(6): p. e202420742.
[3] Qin, Z., et al., Synergistic effect of molecular sieving and adsorption inhibition in MOF-based mixed matrix membranes for efficient O2/N2 separation. Chemical Engineering Journal, 2024. 497: p. 154615.
[4] Araújo, T., et al., Cellulose-based carbon membranes for gas separations - Unraveling structural parameters and surface chemistry for superior separation performance. Carbon, 2023. 204: p. 398-410.