This week’s publications cover a wide range of issues related to a number of CDR methods such as direct air capture, soil carbon sequestration, afforestation and carbon mineralization.
Investigation of the Decarbonization Performance of K2CO3/ZrO2 Adsorbent for Direct Air Capture
Abstract
Direct Air Capture (DAC) technology has gained recognition as a promising approach to achieving negative carbon emissions. Among the various adsorbents investigated, alkali metal-based composite solid adsorbents have exhibited significant potential for DAC applications due to their favorable adsorption characteristics. However, these adsorbents currently face challenges such as high adsorption–desorption temperatures and low cycling efficiency, which constrain their practical utilization. In this study, a K2CO3/ZrO2 composite DAC adsorbent was synthesized using an impregnation method. The decarbonization performance and microscopic characteristics of the adsorbent were systematically investigated using a self-constructed fixed-bed DAC experimental platform in conjunction with various characterization techniques, including X-ray diffraction (XRD), low-temperature nitrogen adsorption, scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS), CO2 temperature-programmed desorption (CO2-TPD), and thermogravimetric-mass spectrometry (TG-MS). The effects of K2CO3 loading, adsorption time, temperature, humidity, and cycling number on the CO2 adsorption performance of the adsorbent were systematically analyzed, with an emphasis on elucidating the underlying mechanisms. The use of ZrO2 as a carrier reduces the regeneration temperature of the adsorbent compared to some reported alkali metal adsorbents. Sensitivity analysis revealed that relative humidity exerts the most significant influence on the CO2 capture capacity of the KZr30 adsorbent. Under optimal experimental conditions (30 % active component loading, adsorption temperature of 30 °C, and relative humidity of 70 %), the adsorbent achieved a CO2 adsorption capacity of 1.18 mmol/g in 5 h, and retained over 92 % of its initial capacity after 10 adsorption–desorption cycles. These results demonstrate the excellent potential of KZr30 adsorbent for continuous DAC-based decarbonization.
Qi, Z. et al. (2025) Investigation of the Decarbonization Performance of K2CO3/ZrO2 Adsorbent for Direct Air Capture 509 (161420) Chemical Engineering Journal.
Read the full paper here: Investigation of the Decarbonization Performance of K2CO3/ZrO2 Adsorbent for Direct Air Capture I Chemical Engineering Journal.
Superstructure optimisation of direct air capture integrated with synthetic natural gas production
Abstract
This study evaluates two integrated pathways for synthetic natural gas (SNG) production via direct air capture (DAC) and utilisation: Dual-Function Material (DFM) technology and Temperature-Vacuum Swing Adsorption (TVSA) combined with a Sabatier reactor. DFM technology, which combines CO₂ capture and methanation in a single unit, is compared against the more established TVSA-Sabatier process regarding techno-economic feasibility. Superstructure optimisation is employed to assess the performance of these two pathways across various upstream and downstream operating units and to examine the impact of different design factors on economic outcomes.
For a capturing scenario of 10,000 tCO2/year, results indicate that DFM technology presents promise, reaching an estimated cost of $740/tCO2 (assuming a 7 % interest rate) under optimal conditions, comparable to the TVSA-Sabatier pathway. Sensitivity analysis underscores the importance of interest rates, energy prices, and carbon credits, highlighting the potential of policy support in facilitating DFM technology. Comparative findings suggest that DFM can potentially reduce equipment complexity and energy use through in situ heat integration however, it requires further thermo-kinetic analysis and experimental validation. Future research is needed on kinetic modelling of DFM’s and advancements are also required in material adsorption performance, more cost-effective catalyst alternatives, and addressing limitations related to pressure drop in further process intensification efforts.
This study offers a comprehensive benchmark for DAC-to-SNG processes, indicating that while DFM technology demonstrates potential for streamlined operations and cost savings, targeted advancements are essential for commercial viability, contributing critical insights to sustainable carbon capture and utilisation strategies.
Dolat, M. et al. (2025) Superstructure optimisation of direct air capture integrated with synthetic natural gas production 125413 (384) Applied Energy.
Read the full paper here: Superstructure optimisation of direct air capture integrated with synthetic natural gas production I Applied Energy
Expanding the Potential Soil Carbon Sink: Unraveling Carbon Sequestration Accessory Genes in Vermicompost Phages
Abstract
The compost microbiome is important in regulating soil carbon sequestration. However, there is limited information concerning phage communities and phage-encoded auxiliary metabolic genes (AMGs) in compost-applied soils. We combined metagenomics and meta-viromes to explore the potential role of bacterial and phage communities in carbon sequestration in the compost microbiome. The experiment comprised swine manure compost (SW) and vermicompost (VE) applied to the soil along with a control treatment (CK). The bacterial community richness decreased after swine manure application and increased after vermicomposting compared to the control treatment. The phage community in the vermicompost-applied soil was dominated (63.1%) by temperate phages. In comparison, the communities of the swine manure compost-applied soil (92.7%) and control treatments (75.4%) were dominated by virulent phages. Phage-encoded carbon sequestration AMGs were detected in all three treatments, with significant enrichment in the vermicompost-applied soil. The average carbon sequestration potential (the coverage ratio of phage AMGs:total genes) of phage AMGs (aceF, GT11, and GT6) in the vermicompost-applied soil (65.18%) was greater than in the swine manure-applied (0) and control soils (50.21%). The results highlight the role of phage-encoded AMGs in improving soil carbon sequestration in vermicompost-applied soil. The findings provide new avenues for increasing soil carbon sequestration.
Yuan, S. et al. (2025) Expanding the Potential Soil Carbon Sink: Unraveling Carbon Sequestration Accessory Genes in Vermicompost Phages 0 (0) Applied and Environmental Microbiology.
Read the full paper here: Expanding the Potential Soil Carbon Sink: Unraveling Carbon Sequestration Accessory Genes in Vermicompost Phages I Applied and Environmental Microbiology.
Optimizing afforestation pathways through economic cost mitigates China’s financial challenge of carbon neutrality
Abstract
Carbon removal and emission reductions simultaneously play a decisive role in carbon neutrality. Yet, different from the structural upgrades in emission reduction, carbon removal through afforestation often heavily relies on specific geographical space. Although carbon neutrality pathways that overlook spatial details play a significant role, the challenge of spatiotemporal equilibrium linked with carbon neutrality exacerbates the economic risks of joint abatement by both parties. Here, we assessed cost-optimal pathways for afforestation in China up to 2060 by incorporating marginal abatement cost curves derived from spatial decomposition of afforestation into a dynamic multi-model analysis of joint abatement. Our findings reveal that afforestation needs to play an increasingly important role in climate mitigation from 2020 to 2060, while the share of emissions reduction needs to gradually decrease. Afforestation policies and actions under carbon neutrality should be coordinated with emissions reduction efforts, aiming to achieve cost-optimal joint abatement, which can be an important source of climate mitigation efforts and address the financial challenges of carbon neutrality. Moreover, the intertemporal cost-optimal maps to carbon neutrality through afforestation observed significant spatiotemporal variability of cost-optimal areas. Hence, focusing afforestation efforts on cost-optimal areas during specific periods can be another important way of addressing the financial challenges.
Zhang, X. et al. (2025) Optimizing afforestation pathways through economic cost mitigates China’s financial challenge of carbon neutrality 119 (6) Communications Earth & Environment.
Read the full paper here: Optimizing Afforestation Pathways through Economic Cost Mitigates China’s Financial Challenge of Carbon Neutrality I Communications Earth & Environment.
Unraveling Carbon Mineralization Patterns and Mechanisms in Conservation Agriculture: A Global Synthesis and Multi-Point Experiment
Abstract
The mineralization of soil organic carbon (SOC) profoundly impacts the efficiency of SOC sequestration, crucial for the long-term stable carbon (C) sequestration in soil. Despite its significance, systematic studies investigating the effects of three pillars of conservation agriculture (CA), i.e., no-till, residue retention (RR), and crop rotation (CR), on the mineralization of SOC remain scarce. To address the gap, we conducted a comprehensive analysis, collating data from 89 experimental sites worldwide and integrating with field experimental data sampled from 10 sites across China. Our study evaluated potentially mineralizable carbon (PMC) using first-order kinetic fitting, and specific PMC (SPMC, PMC/SOC) to elucidate patterns of SOC mineralization under CA and its moderation by climatic, environmental, and soil factors. The results showed a gradual decrease in PMC with the adoption of increasing numbers of CA pillars, with the full implementation reducing PMC by 35.1%. The impact of no-till on PMC and SPMC was not significant, while RR and CR significantly increased and decreased PMC by 21.0% and 27.3%, respectively. Notably, only CR significantly increased SPMC by 15.0%. The findings suggest that under CR, PMC exhibit reduced sensitivity to climatic and environmental changes and emphasizing higher environmental stability of SOC. Soil microbial indicators demonstrated direct and indirect positive regulatory effects on PMC, and SPMC is positively affected by MBC in addition to SOC, both of which indicate the vital role of soil microbes in regulating SOC mineralization. We proposed a conceptual model highlighting nonlinear relationship between stable SOC pool and SOC, emphasizing how the relationship between C sequestration and emission reduction can be optimized under CR. Further research should delve into understanding microbial pathways in SOC mineralization and their role in balancing mineralization and sequestration.
He, C. et al. (2025) Unraveling Carbon Mineralization Patterns and Mechanisms in Conservation Agriculture: A Global Synthesis and Multi-Point Experiment 493 (144900) Journal of Cleaner Production.
Read the full paper here: Unraveling Carbon Mineralization Patterns and Mechanisms in Conservation Agriculture: A Global Synthesis and Multi-Point Experiment I Journal of Cleaner Production.