A new life-cycle assessment comparing the production impacts of three materials used in carbon dioxide capture technology has highlighted the environmental trade-offs involved in using such materials. The research, published in the International Journal of Global Warming, analysed the emissions associated with manufacturing, a so-called “cradle-to-gate” analysis. The results offer new insights into whether the use of such materials can truly be sustainable in part of how we address climate change.
Namra Mir, Yusuf Bicer, Fadwa El-Mellouhi, Elumalai Palani, Satyanarayana Bonakala, and Abdulkarem I. Amhamed of Hamad Bin Khalifa University, Doha, Qatar, have looked at various porous materials, which can “adsorb” gases from the air. These include natural minerals known as zeolites and their synthetic counterparts, metal-organic frameworks (MOFs). Depending on the exact chemical structure of these materials, they can be produced to adsorb specific gases, such as the greenhouse gas carbon dioxide, in preference to others.
As global efforts to reach net-zero emissions are intensifying, so carbon dioxide capture technology continues to be of interest. It could be used to offset emissions from industrial and other sectors that would be very hard to decarbonize, such as cement production and transport.
The study focused on three porous materials with potential for carbon capture. Specifically, the team looked at TCM-14, referred to as MOF-1, and two hybrid zeolite-based materials, zeolite 13X with diethylenetriamine (MOF-2) and zeolite A with methanol (MOF-3). They then calculated the emissions associated with producing these materials for use in carbon capture technology.
Among the three, MOF-1 had the lowest environmental footprint at 3.5 kg carbon dioxide equivalent per kilogram of material. The two hybrid zeolite materials had significantly higher emission potential at around 14 kg of carbon dioxide each per kilogram manufactured. This suggests that despite its greater chemical complexity, MOF-1 may be the more sustainable option in terms of its initial environmental burden.
However, the team points out that despite this advantage, manufacturing MOF-1 is an energy-intensive process because it has to be carried out at a very high temperature. For the zeolite-based materials, the chemical modifiers used can lead to even worse manufacturing emissions, with one particular additive used to improve adsorption, leading to carbon dioxide emissions of well over 40 kilograms per kilogram of adsorbent material produced.
The work emphasises that we cannot evaluate a technology developed to combat climate change solely on its performance, we must take into account the energy and emissions costs as well as the resources costs of manufacturing and maintaining that technology.
Mir, N., Bicer, Y., El-Mellouhi, F., Palani, E., Bonakala, S. and Amhamed, A.I. (2025) ‘Life cycle assessment of sustainable metal-organic frameworks and zeolites’, Int. J. Global Warming, Vol. 36, No. 1, pp.23–33.