Atmospheric methane capture by zeolites

Cobo et al's (2023) review assigns methane oxidation in general a very low technological readiness level.

Nisbet Jones et al (2021) write that zeolite-using devices are already in widespread use, for example by oxygen concentrators in use in hospitals. According to the authors, this makes it more likely that zeolite-based methane capture could be more easily scaled up than other more experimental technologies. However, given the relative novelty around the usage of zeolites for methane capture, many questions remain open. Moreover, not all zeolite structures are useful, as Kim et al (2013) showed after screening over 87,000 zeolite structures for their capture potential.

Due to the urgency given to methane mitigation, there seems to be great potential for future developments, with an MIT team working on the idea receiving a $2 million development grant from the U.S. Department of Energy (news.mit.edu/2022/dirt-cheap-solution-common-clay-materials-may-help-curb-methane-emissions).

Scaling up is a major issue of concern to all methane capture technologies given the low methane concentrations and therefore large amounts of air required (Lackner, 2020; Jackson, 2021). Zeolites too would be much more effective close to sources of concentrated emissions. This could limit the effective scalability.

However, due to the low costs and energy requirements, zeolites application could also be relatively easily scalable, with economies of scale potentially probably down costs further. Moreover, the chemical process releases heat, and air with above 0.5 percent concentration of methane would provide more energy than was required to start the process (Brenneis et al, 2021). This means such devices could be used to generate energy when deployed near very concentrated sources. 

Some zeolites can capture methane at room temperature, and because the goal would be to transform CH4 into CO2, and the transformed methane could be released after its transformation into carbon dioxide, there would be no need for the construction and maintenance of compression, purification, storage or related infrastructure (Ming et al 2022). This could mean that potential application could be done at many and diverse sites, rather than other capture techniques relying on storage (see DACCS, BECCS, and CCS).

Methane mitigation holds the promise of providing major climate benefits in a short timespan (IPCC AR6 WG3, 2022; Sawyer et al, 2022).

Nisbet Jones et al, 2021 write that the already widespread use of similar techniques in other areas, they believe they ‘could likely be readily upscaled in a way that a more experimental technology could not, which is a significant advantage when dealing with the immediate need for decarbonization’. However, in a short comment in Nature Sustainability Klaus Lackner (2020) also notes that the short lifetime of tropospheric methane in comparison to CO2 requires methane destruction measures to treat significant amounts of air to make a meaningful difference.

There have been no studies on the potential role of zeolites for Arctic methane. Physically, zeolite-based methane capture devices would ideally be placed close to point source emissions. Because this method to capture methane would not need storage facilities and related infrastructure, some of the objections against DACCS and BECCS sites for remote regions of the Arctic do not apply to zeolite capture facilities.