CO2-removal News

Peer-reviewed Publications

Fakhraddinfakhriazar et al. (2026): Stability of Adsorbents for Direct Air Capture (DAC): Challenges and Perspectives

Salar Fakhraddinfakhriazar, Cristhian Molina-Fernández and Grégoire Léonard, IN: Energy & Fuels, https://doi.org/10.1021/acs.energyfuels.5c05460

Direct air capture (DAC) technologies, particularly adsorption-based systems, are advancing rapidly as a form of negative emission technologies (NETs). DAC technologies represent a promising engineering approach to addressing diffuse CO₂ emissions and provide several deployment advantages, including flexibility and scalability. However, a critical yet often overlooked challenge of adsorption-based DAC is the limited stability of CO₂ sorbent materials, which undermines sustainability and hinders large-scale deployment. While most research has focused on developing adsorbents with high CO₂ selectivity and capacity, stability remains a crucial criterion, investigated in some studies through multicycle testing and exposure to accelerated degradation environments. This review provides a brief overview of DAC adsorbent types, followed by a detailed analysis of existing studies on the stability of solid sorbents under DAC operating conditions, highlighting key findings and research gaps.

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Peer-reviewed Publications

Cobo et al. (2026): Negative emissions technologies and practices could challenge global resource supply and environmental limits

Selene Cobo, Ángel Galán-Martín and Gonzalo Guillén-Gosálbez, IN: Communications Earth & Environment, https://doi.org/10.1038/s43247-026-03348-8

Meeting climate goals will most likely require large-scale carbon dioxide removal, yet its sustainability implications remain poorly understood. Here, the authors conduct a prospective life cycle assessment of multiple negative emissions technologies and practices, integrating mineral resource, health, and absolute sustainability indicators to quantify impacts between 2030 and 2050.

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Peer-reviewed Publications

Schwinger et al. (2026): Assessing Earth system responses in deep mitigation scenarios with activity-driven simulation of carbon dioxide removal

Jörg Schwinger, Leon Merfort, Nico Bauer, Raffaele Bernadello, Momme Butenschön, Timothée Bourgeois, Matthew J. Gidden, Shraddha Gupta, Hanna Lee, Nadine Mengis, Yiannis Moustakis, Helene Muri, Lars Nieradzik, Daniele Peano, Julia Pongratz, Pascal Sauer, Etienne Tourigny and David Wårlind, IN: EGUsphere, https://doi.org/10.5194/egusphere-2026-833

Assessing Earth system responses arising from carbon dioxide removal (CDR) requires developing and simulating pairs of scenarios – a mitigation scenario with deployment of CDR and a corresponding no-CDR baseline. The latter describes a world where no CDR is deployed, such that net carbon emissions are higher and a given temperature target may be missed. While over the past years a rich literature on deep mitigation scenarios with CDR has been emerging, no-CDR baselines have mostly been explored in stylized Earth system model (ESM) experiments. In such simulations, a no-CDR baseline simply assumes that CDR is “switched off”, while socio-economic constraints are not considered. However, the deployment of CDR in deep mitigation scenarios, created by integrated assessment models (IAMs), is embedded in a consistent socio-economic description of plausible futures, and disallowing CDR may affect climate drivers due to changes in the energy system and in land-use dynamics. Particularly, when moving towards an activity-driven representation of CDR in emission-driven ESMs, where the activity that draws down CO₂ from the atmosphere is explicitly modelled, the creation of no-CDR baselines comes with challenges and trade-offs. Here, the authors conceptualize a framework for emission-driven ESM simulations of IAM scenarios that allows them to determine carbon-cycle and biogeophysical feedbacks of CDR deployment using no-CDR baselines.

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Peer-reviewed Publications

Olasehinde et al. (2026): Socio-economic implications of deploying COP28 pledged negative emission technologies

Daniel O. Olasehinde, Olusola Bamisile, Caroline Acen, Chukwuebuka Ejiyi and Qi Huang, IN: Carbon Capture Science & Technology, https://doi.org/10.1016/j.ccst.2026.100590

Achieving the Paris Agreement’s targets will inevitably impose financial burdens, but choosing the most economically viable path is critical. At COP28, countries pledged to triple renewable energy capacity to 11,000 GW and double energy efficiency gains to 4 % annually by 2030. The agriculture, forestry, and land use (AFOLU) sector also committed to reducing emissions and enhancing carbon dioxide removal (CDR). Using the En-ROADS modeling tool, this study evaluates five global scenarios combining varying degrees of fossil fuel reduction and CDR deployment: Ref (based on current COP28-aligned pledges), Ref++ (Ref with added fossil fuel taxes and carbon pricing), limCDR (Ref++ plus limited deployment of technological CDR up to 50 % of its potential), modCDR (Ref with moderate CDR deployment up to 65 % of potential, but no fossil fuel taxation), and allCDR (Ref with full utilization of technological CDR potential and no fossil fuel taxation). While population growth is held constant across all scenarios, economic outcomes diverge.

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Peer-reviewed Publications

Pavia & Lambert (2026): Carbon dioxide removal by enhanced weathering on American green clay tennis courts

Frank J. Pavia and Jonathan E. Lambert, IN: Applied Geochemistry, https://doi.org/10.1016/j.apgeochem.2026.106737

40,000 tennis courts in the United States are constructed and maintained by spreading basalt feedstock similar to that used for carbon dioxide removal via enhanced rock weathering. Silicate weathering therefore readily occurs on these courts, yet the carbon sequestration associated with this weathering has never been quantified. The authors have built a model that quantifies net CO₂ sequestration during the lifetime of green clay tennis courts. They calculate gross CO₂ sequestration rates associated with silicate weathering and conduct a lifecycle analysis for emissions during court construction. This allows them to determine net sequestration rates at each court as well as assess the factors that lead to maximal CO₂ sequestration at different sites.

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Peer-reviewed Publications

Bicer et al. (2026): Integrated DAC-HVAC systems for CO₂ capture and sustainable hydrogen production from condensed water

Y Bicer, I Ghiat, Y M Abdullatif, A Banu, T Al-Ansari and A I Amhamed, IN: IOP Conference Series: Earth and Environmental Science, https://doi.org/10.1088/1755-1315/1587/1/012019

Carbon dioxide removal is essential to meet net-zero targets and stay within the 1.5 °C climate goal, with Direct Air Capture (DAC) technologies playing a critical role in removing both current and historical emissions. In parallel, low/zero-carbon fuels such as green hydrogen play a crucial role in decarbonizing hard-to-abate sectors and enabling a clean energy transition. This study introduces a novel integration of DAC technology within building Heating, Ventilation, and Air Conditioning (HVAC) systems, designed to recover water from the DAC cycle for sustainable hydrogen production. In the Temperature-Vacuum Swing Adsorption (TVSA) process, water condenses as a byproduct during the desorption phase. This condensed water can be repurposed as a feedstock for green hydrogen production via electrolysis, offering a sustainable water input for proton exchange membrane (PEM). By coupling DAC with hydrogen generation, the system supports both negative emissions and clean fuel production. The HVAC-integrated DAC system reduces energy demand by leveraging the building’s exhaust air stream, which exhibits relatively stable temperature and humidity levels. This integration not only lowers the thermal requirements of the DAC process but also reduces HVAC energy consumption through increased air recirculation. In addition to energy benefits, the system contributes to improved indoor air quality by removing carbon dioxide from indoor environments, where concentrations often exceed 1000 ppm. The system uses a solid sorbent of SBA-15 functionalized with tetraethylenepentamine (TEPA) in a TVSA cycle. A thermodynamic analysis was conducted, which was used in the economic analysis to size equipment, estimate their base costs, and quantify operational costs.

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Peer-reviewed Publications

Sarmah et al. (2026): Systematic review on proliferation of microalgae and carbon sequestration potential for sustainability

Mitrakhi Sarmah et al., IN: PubMed, https://pubmed.ncbi.nlm.nih.gov/41731188/

Rising atmospheric CO₂ underscores the need for carbon mitigation strategies. Microalgae have emerged as a promising nature-based solution due to their exceptional photosynthetic efficiency, rapid biomass production, and adaptability to diverse environmental conditions. It satisfies the mandate of different sustainable development goals viz. SDG-02, 06, 07, 09, 12 and 13. This study investigates the carbon sequestration potential of various microalgae along with different microalgal cultivation systems, factors affecting cultivation, genetic interventions and solution-based applications. It was investigated that carbon sequestration potential of various microalgal strains varied in between 0.06 and 2.57 g L⁻¹ d⁻¹, where Haematococcus pluvialis exhibited the highest rate (2.57 g L⁻¹ d⁻¹). Among the different types of microalgae cultivation systems, the biofilm reactors and hybrid reactor designs were evaluated for higher efficiency. Environmental and operational factors influencing carbon fixation capacity are critically compared. The study explores genetic interventions for enhanced microalgal productivity both quantitatively and qualitatively.

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Peer-reviewed Publications

Danzer & Kirchengast (2026): Bringing fairness also into carbon removal shares of countries is essential for a just transition

Julia Danzer and Gottfried Kirchengast, IN: Global Environmental Change, https://doi.org/10.1016/j.gloenvcha.2026.103114

Towards achieving the Paris goal of limiting global warming to well below 2°C with an effort to reach 1.5°C, countries not only need to drastically reduce their emissions but also to partially deploy carbon dioxide removal (CDR). CDR from the atmosphere can be achieved by various methods, ranging from nature-based solutions to technical options. The authors started with a survey of recent studies and found mounting evidence that CDR use needs great caution, since there exist strong biophysical and socio-economic constraints on scaling it up; and emission and removal fluxes are not equivalent in terms of climate outcomes.

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Peer-reviewed Publications

Sheng et al. (2026): The forest carbon paradox: novel insights into China’s forest-economy-emissions relationships

Zhelin Sheng, Kaimei Zhang, Chen Ling, Wenjuan Shen, Zihan Zhang, Chuanxin Ma, Changlei Xia, Keyi Chen, Yu Shen, Yu Hao and Jiangang Han, IN: npj Climate Action, https://doi.org/10.1038/s44168-026-00350-w

Forest-climate-economy relationships present critical challenges for climate mitigation in rapidly developing economies. While forests are traditionally viewed as carbon sinks, their effectiveness as tradable carbon products remains difficult to quantify in the near term due to time lags and scale mismatch with energy-driven emissions dynamics. This study examines these relationships in China using data from 30 provinces (from 2000 to 2019). Using LSTM-MLP hybrid models and multispatial Convergent Cross Mapping, the authors reveal what they term the “forest carbon paradox”: despite China’s extensive afforestation efforts increasing forest coverage significantly, these initiatives demonstrate limited immediate impact on CO₂ emissions and GDP trajectories.

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Peer-reviewed Publications

Zhang et al. (2026): Durability and CO₂ sequestration capacity of carbon sequestration foamed concrete under magnesium and sodium sulfate attacks

Xiang Zhang, Songyu Liu, Kai Wu, Zhenyang Yuan, Zengfeng and Guojun Cai, IN: Construction and Building Materials, https://doi.org/10.1016/j.conbuildmat.2026.145506

Carbon sequestration foamed concrete (CFC) is primarily composed of MgO, serpentine, silty clay, water and carbon dioxide (CO₂) foam. CFC has been extensively studied in previous literature for its exceptional performance in CO₂ sequestration. However, the lack of studies on the durability of CFC under sulfate attack remains a significant challenge for its large-scale application as a building material. This study investigated the durability and CO₂ sequestration of CFC under chemical sulfate attack by evaluating the changes in specimen volume, mass, phase identification and CO₂ sequestration capacity. The CFC specimens were exposed to magnesium sulfate (MgSO₄) and sodium sulfate (Na₂SO₄) solutions for 10, 20 and 30 days, respectively, after which a series of tests were conducted.

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