Membrane Separation Technology in Direct Air Capture

Abstract

Direct air capture (DAC) is an emerging negative CO2 emission technology that aims to introduce a feasible method for CO2 capture from the atmosphere. Unlike carbon capture from point sources, which deals with flue gas at high CO2 concentrations, carbon capture directly from the atmosphere has proved difficult due to the low CO2 concentration in ambient air. Current DAC technologies mainly consider sorbent-based systems; however, membrane technology can be considered a promising DAC approach since it provides several advantages, e.g., lower energy and operational costs, less environmental footprint, and more potential for small-scale ubiquitous installations. Several recent advancements in validating the feasibility of highly permeable gas separation membrane fabrication and system design show that membrane-based direct air capture (m-DAC) could be a complementary approach to sorbent-based DAC, e.g., as part of a hybrid system design that incorporates other DAC technologies (e.g., solvent or sorbent-based DAC). In this article, the ongoing research and DAC application attempts via membrane separation have been reviewed. The reported membrane materials that could potentially be used for m-DAC are summarized. In addition, the future direction of m-DAC development is discussed, which could provide perspective and encourage new researchers’ further work in the field of m-DAC.

Process Operability Analysis of Membrane-Based Direct Air Capture for Low-Purity CO2 Production

“…Adding to the portfolio of separation technologies that can be applied for DAC, the use of gas separation membranes has also been considered in this context. − Membrane-based direct air capture (m-DAC) offers several advantages such as simple setup and operations due to its modular design, allowing for easy adaptation to different capture unit sizes and geographical locations. Additionally, membranes eliminate the need for a regeneration step, potentially reducing the energy costs associated with it.…”

On the Maximum Obtainable Purity and Resultant Maximum Useful Membrane Selectivity of a Membrane Separator

“…Gas separations represent a growing market segment, with several potential applications including carbon capture [ 1 , 2 ], hydrogen purification [ 3 ], and chemical upgrading [ 4 ]. Compared to pressure-swing adsorption or cryogenic distillation, membrane separators do not require the energy-intensive processes of pressure or thermal cycling.…”