CO2-removal news

Peer-reviewed Publications

Wang et al. (2023): Verification Method of Direct Air Capture by Cementitious Material Using Carbon Isotopes

Zhenzhen Wang, Abudushalamu Aili, Masayo Minami, Ippei Maruyama IN: Journal of Advanced Concrete Technology,  21, 11, https://doi.org/10.3151/jact.21.934

This study proposes an experimental method to track the origin of cement paste that fixes CO2 directly from the air under natural conditions. By exposing powders of well-hydrated cement paste to air, carbonated cement paste powders are obtained with different carbonation degrees. The inorganic carbon of these carbonated samples is extracted by dissolution in phosphoric acid, and the isotopic characteristics related to 13C and 14C are measured.

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Peer-reviewed Publications

Drexler et al. (2023): Carbon storage in old hedgerows: The importance of below-ground biomass

Sophie Drexler, Eiko Thiessen, Axel Don IN: GCB-Bioenergy, https://doi.org/10.1111/gcbb.13112

The establishment of new hedgerows is increasingly attracting attention as a C sequestration measure. Despite hedgerows being a traditional agroforestry system, few studies have been conducted on hedgerow C stocks. Data on below-ground biomass (BGB) in particular are limited. The aim of this study was therefore to quantify both above-ground biomass (AGB) and BGB C stocks, as well as litter and soil organic C stocks, of established hedgerow systems by destructive sampling at three sites in northern Germany.

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Peer-reviewed Publications

Ofiti et al. (2023): Climate warming and elevated CO2 alter peatland soil carbon sources and stability

Nicholas O. E. Ofiti, Michael W. I. Schmidt, Samuel Abiven, Paul J. Hanson, Colleen M. Iversen, Rachel M. Wilson, Joel E. Kostka, Guido L. B. Wiesenberg, Avni Malhotra IN: Nature Communications, 14, https://doi.org/10.1038/s41467-023-43410-z

Here, the authors examine the impact of warming and elevated atmospheric CO2 concentration (eCO2) on the molecular composition of soil organic carbon (SOC) to infer SOC sources (microbe-, plant- and fire-derived) and stability in a boreal peatland. They show that while warming alone decreased plant- and microbe-derived SOC due to enhanced decomposition, warming combined with eCO2 increased plant-derived SOC compounds. The authors further observed increasing root-derived inputs (suberin) and declining leaf/needle-derived inputs (cutin) into SOC under warming and eCO2. The decline in SOC compounds with warming and gains from new root-derived C under eCO2, suggest that warming and eCO2 may shift peatland C budget towards pools with faster turnover.

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Peer-reviewed Publications

Xiong et al. (2024): Seaweed farming environments do not always function as CO2 sink under synergistic influence of macroalgae and microorganisms

Tianqi Xiong, Hongmei Li, Yubin Hu, Wei-dong Zhai, Zhe Zhang, Yi Liu, Jihong Zhang, Longfei Lu, Lirong Chang, Liang Xue, Qinsheng Wei, Nianzhi Jiao, Yongyu Zhang IN: Agriculture, Ecosystems & Environment 361, 108824, https://doi.org/10.1016/j.agee.2023.108824

Through in-situ mesocosm cultivation experiments and eight field investigations covering different kelp growth stages in an intensive farming area in China, we found that compared with the surrounding seawater without kelps, the seawater at the fast-growth stage of kelp was a sink of CO2 (pCO2 decreased by 17−73 μatm), but became a source of CO2 at the aging stage of kelp (pCO2 increased by 20−37 μatm).

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German News

Deutschlands radikaler Dreifach-Plan für die Weltklimakonferenz

focus.de, 26.11.2023, 22:16 Uhr

“Die anstehende Klimakonferenz – auch COP28 genannt – ist schon das 28. Treffen dieser Art. Was soll das Ganze also eigentlich noch? Zweifel sind berechtigt. Die Prozesse sind schwerfällig, die Vereinbarungen oft freiwillig. Und doch: Allein die Tatsache, dass sich Vertreter von rund 200 Staaten zusammenfinden, ist nicht selbstverständlich. Alle beteiligten Staaten, selbst China oder Russland, erkennen damit de facto an: Wir haben ein gemeinsames Problem. Ein Überblick, um welche vier Punkte es dabei geht – und was auf dem Spiel steht.”

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Peer-reviewed Publications

Lefvert & Grönkvist (2023): Lost in the scenarios of negative emissions: The role of bioenergy with carbon capture and storage (BECCS)

Adrian Lefvert, Stefan Grönkvist IN: Energy Policy, 113882, https://doi.org/10.1016/j.enpol.2023.113882

With this policy perspective article the authors question the ongoing discussion about the use of biomass for BECCS with basis in three points: (1) under the enhanced transparency framework under the Paris agreement, all parties to the agreement will use the same guidelines to estimate emissions by sources and removals by sinks, in which the emissions and removals in connection to cultivation of biomass are accounted for in the land-use, land-use change and forestry (LULUCF) sector, (2) adding carbon capture to existing processes may lead to a shift in products from that process rather than an increase in biomass use, and (3) BECCS requires substantial financial incentives.

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Peer-reviewed Publications

Wu et al. (2023): Facile synthesis of structured adsorbent with enhanced hydrophobicity and low energy consumption for CO2 capture from the air

Junye Wu, Yanlin Chen, Yifei Xu, Siyu Chen, Haotian Lv, Zhuozhen Gan, Xuancan Zhu, Ruzhu Wang, Chi-Hwa Wang, Tianshu Ge IN: Matter, https://doi.org/10.1016/j.matt.2023.10.019

Formulating materials into structured configurations is important to improve CO2 capture efficiency. Here, the hydrophobic polystyrene-block-polybutadiene-block-polystyrene (SBS) is used as the binder to coat polyethyleneimine (PEI) mesoporous cellular foam (MCF) onto ceramic fiber honeycombs. It not only makes the powder attach stably and uniformly on the honeycomb but also maintains the porosity for favorable CO2 diffusion. The synthesis was optimized, and a capacity of 0.71 mmol g−1 composite (or 2.33 mmol g−1 adsorbent) in 400 ppm CO2 is presented. The SBS endows the structured adsorbent with enhanced hydrothermal stability, as verified by the steam purge and accelerated stability experiments.

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Peer-reviewed Publications

Zolfaghari et al. (2023): Simulation of Carbon Dioxide Direct Air Capture Plant Using Potassium Hydroxide Aqueous Solution: Energy Optimization and CO2 Purity Enhancement

Zahra Zolfaghari, Alireza Aslani, Rahim Zahedi, Sina Kazzazi IN: Energy Conversion and Management, 100489, https://doi.org/10.1016/j.ecmx.2023.100489

The present study adopts the high-temperature DAC method with an aqueous KOH absorbent as its focus, aiming to mitigate energy consumption. Given that a substantial portion of energy consumption in comparable processes can be attributed to the calciner and slaker units, our research centers its attention on the Air Separation Unit (ASU) and the steam cycle unit, investigating their impact on the system’s production capacity, the enhancement of CO2 purity, and the augmentation of equipment thermal recovery. Process optimization, results a remarkable increase in heat recovery (21.1%) and significant reductions in utilities consumption.

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