Search Results (1,334)

Peatlands are the most efficient terrestrial ecosystems for long-term carbon (C) storage. In Ireland, approximately 84% of raised bogs are degraded, contributing an estimated emission of 1.9 Mt C year⁻¹, nearly one-third of which originates from domestic peat extraction sites. Rewetting aims to reduce C emissions and restore sequestration capacity; however, immediate post-restoration effects remain poorly quantified. We investigated the short-term impact of rewetting on C fluxes over a 3-year period at a former domestic peat extraction site. CO₂ and CH₄ fluxes were measured across rewetted and adjacent unrestored areas with matched ecotopes (vegetation communities). Results show that rewetting led to substantial reductions in C emissions across all ecotopes. Compared to unrestored areas, the Sub-marginal and Facebank ecotopes had lower average annual C emissions by 0.88 and 0.74 t C ha⁻¹, respectively. In the cutover bog, rewetting reduced emissions in Eriophorum and Molinia ecotopes by 2.17 and 0.59 t C ha⁻¹ year⁻¹, respectively. This study demonstrates that rewetting led to immediate carbon reduction, and can deliver immediate climate mitigation benefits. Expanding restoration to include undesignated domestic extraction bogs offers a cost-effective strategy to reduce emissions from degraded peatlands in the near term. Full article

To clarify the characteristics of CO₂–formation water–rock reactions in tight sandstones and their effects on CO₂-enhanced oil recovery (EOR) efficiency and storage efficiency, this study takes the tight oil reservoirs of the Changqing Jiyuan Oilfield as the research object. A variety of experimental techniques, including ICP-OES elemental analysis, powder X-ray diffraction, and scanning electron microscopy, were employed to systematically investigate the mechanisms and main influencing factors of water–rock reactions during CO₂ geological storage. The study focused on analyzing the roles of mineral composition, reservoir pore structure, and formation water chemistry in the reaction process. It explored the potential impacts of reaction products on reservoir properties. Furthermore, based on the experimental results, a coupled reservoir numerical simulation of CO₂ injection for EOR and storage was conducted to comprehensively evaluate the influence of mineralization processes on CO₂ EOR performance and long-term storage efficiency. Results show that the tight sandstone reservoirs in Jiyuan Oilfield are mainly composed of calcite, quartz, and feldspar. The dominant water–rock reactions during CO₂ formation–water interactions are calcite dissolution and feldspar dissolution. Among these, calcite dissolution is considered the controlling reaction due to its significant effect on the chemical composition of formation water, and the temporal variation in other elements shows a clear correlation with the calcite dissolution process. Further analysis reveals that water–rock reactions lead to permeability reduction in natural fractures near injection wells, thereby effectively improving CO₂ EOR efficiency, enhancing sweep volume, and increasing reservoir recovery. At the end of the EOR stage, mineralized CO₂ storage accounts for only 0.53% of the total stored CO₂. However, with the extension of time, mineralized storage gradually increases, reaching a substantial 31.08% after 500 years. The study also reveals the effects of reservoir temperature, pressure, and formation water salinity on mineralization rates, emphasizing the importance of mineral trapping for long-term CO₂ storage. These findings provide a theoretical basis and practical guidance for the joint optimization of CO₂ EOR and geological sequestration. Future research may further focus on the dynamic evolution of water–rock reactions under different geological conditions to enhance the applicability and economic viability of CO₂ storage technologies. Full article

Urban trees play a critical role in mitigating climate change by capturing atmospheric CO₂ and providing multiple co-benefits, including cooling urban environments, reducing building energy demand, and enhancing citizens’ physical and psychological well-being. This study presents the Co Carbon Trees Measurement project, a citizen science initiative implemented in the city of Viladecans, Spain, involving 658 students, local administration, and academia, three components of the EU mission’s quadruple helix governance model. Over one year, 1274 urban trees were measured for trunk diameter and height to quantify annual CO₂ sequestration using a direct measurement approach combining field data collection with a mobile application for a height assessment and a flexible measuring tape for diameter. Results indicate that carbon fixation increases with tree size, displaying a parabolic function with larger trees sequestering significantly more CO₂. A range between 10 and 20 kg of CO₂ is sequestered by the urban trees in the period 2024–2025. The study also highlights the broader benefits of urban trees, including shading, mitigation of the urban heat island effect, and positive impacts on mental health and social cohesion. While the total CO₂ captured in Viladecans (≈810 tons/year) is small relative to city emissions (≈170,000 tons/year), the methodology demonstrates a scalable, replicable approach for monitoring progress toward climate neutrality and integrating urban trees into planning and climate action strategies. This approach positions green infrastructure as a central component of sustainable and resilient urban development. Full article

Peat mosses of the genus Sphagnum are keystone species in peatland ecosystems and play critical roles in carbon sequestration, nitrogen fixation, and hydrological regulation. Indeed, these ecological functions are largely mediated by endophytic bacteria associated with Sphagnum. Here, five populations of the endemic Chinese moss species, S. multifibrosum, were sampled across southern China in peatland (PH) and rock habitats (RH). High-throughput sequencing of 16S rRNA and nitrogenase (nifH) genes was applied to characterize overall endophytic bacterial diversity and diazotroph diversity associated with S. multifibrosum, respectively, alongside host microsatellite genotyping. Proteobacteria was the dominant endophytic bacterial phylum. The bacterial communities exhibited significant spatial separation between eastern and western communities and community dissimilarities significantly increased with increasing geographic distances. Environmental heterogeneity and host genetics jointly shaped endophytic bacterial community assemblage. Climate was the most important determinant influencing bacterial composition, followed by host genotype and habitat type. Temperature, precipitation, and nitrogen deposition were the primary environmental factors that influenced composition. Bacterial diversity and composition exhibited no statistically significant differences between the two habitats. Further, the richness and abundances of diazotrophs and methanotrophs from PH communities were higher than in RH communities. Co-occurrence network analysis suggested that RH bacterial networks had lower connectance but were more modularized and exhibited higher complexity than PH networks. These results highlight the ecological functions of peat mosses in carbon and nitrogen cycling and suggest a need to prioritize the conservation of S. multifibrosum in peatland environments under global climate change. The results also provide a framework to help future wetland management and biodiversity conservation efforts in China. Full article

The Hetao Irrigation District in Inner Mongolia is a major spring wheat production region in China. To synergize high wheat yield, water conservation, and carbon emission reduction in this region, a 2023 and 2024 field experiment was conducted. This study systematically analyzed the effects of organic fertilizer substitution for chemical nitrogen (T1:0%, T2:25%, T3:50%, T4:75%, T5:100%) on soil carbon emissions dynamics and carbon footprint of wheat fields, under two irrigation regimes: water-saving irrigation (twice at jointing and heading stages, 2W) and conventional irrigation (four times at tillering, jointing, heading, and grain-filling stages, 4W). The results showed that during the wheat-growing season, soil CO₂ emission rate exhibited a single-peak trend (peak at flowering stage), while cumulative soil CO₂ emission showed a “decrease-increase-decrease” pattern (peak at jointing to heading). At different growth stages, both CO₂ emission and its rate increased with higher organic fertilizer substitution ratios, and were higher under 4W than 2W. Irrigation and substitution treatments significantly affected the total carbon emissions, carbon sequestration, and carbon footprint: total emissions increased with substitution ratios, while sequestration and footprint first increased then decreased; all three indices were higher under 4W than 2W. Regression analysis revealed that maximum net carbon budget was achieved at 21.6–31.7% substitution (1402.3–1879.9 kg ha⁻¹) under 2W, and 31.0–33.8% substitution (2295.5–2822.0 kg ha⁻¹) under 4W. In conclusion, water-saving irrigation (900 m³ ha⁻¹ per application at jointing and heading stages) combined with an optimal organic-nitrogen ratio (1008.0 kg ha⁻¹ organic fertilizer, 193.1 kg ha⁻¹ chemical nitrogen) effectively coordinates water conservation and carbon emission reduction. This study provides a basis for synergizing these goals in Hetao’s wheat production. Full article

Environmental Protection Plans (EPPs) are vital for mitigating the socio-ecological impacts of quarry operations, especially in emerging economies like Thailand, where rapid industrialization often intensifies air, water, noise, and land degradation. This study applies the social return on investment (SROI) framework to evaluate the cost-effectiveness of multi-domain EPPs implemented in a quarry. By applying compliance-based assessment and monetization of environmental and health co-benefits, annual economic outcomes were quantified for particulate matter (PM₁₀), total dissolved solids (TDS), noise reduction, and carbon sequestration. The analysis revealed a high SROI ratio of 59.55:1, primarily driven by substantial health benefits from PM₁₀ and noise abatement. This ratio also reflects consideration of investment from an annual operational cost, with a sensitivity analysis of incorporating an estimated capital expenditure, reducing the ratio to moderate value ranges of 5–10:1. A number of limitations, such as exclusion of capital costs, reliance on fixed proxies, and single-year scope, may overstate short-term returns, suggesting the application of stochastic methods for enhanced robustness. Overall, the findings demonstrate that EPPs deliver substantial economic and public health benefits, supporting their role in fostering community resilience and advancing sustainable operations in quarry sectors. Full article

The aim of this work is to present a technologically feasible method for processing biomass into synthesis gas or hydrogen-rich gas. Three types of biomass with different lignin contents were pyrolyzed in a pyrolysis unit under well-defined conditions (ambient pressure, heating rate of 10 K min⁻¹, end temperature of 500 °C, operating particle size, variable catalyst mass) in the presence of a ruthenium catalyst (Ru/Al₂O₃, powder), and the effect of catalyst amount on the yield and gas composition was observed. Feedstock mass was always 50 g, and catalyst mass was 2.5, 5, and 10 g (mixing ratios 0.05, 0.1, and 0.2, resp.). During pyrolysis, the raw gas and vapors was passed through the catalyst bed and converted to the resulting gas and bio-oil. The gas obtained was cleaned by sequestration with CO₂ using commercial active carbon to obtain syngas with different H₂/CO ratios or hydrogen-rich gas. It was found that, depending on the catalyst amount, slow pyrolysis catalyzed by ruthenium yielded syngas with a H₂/CO ratio of approximately 0.5–5, which is further usable. The by-products obtained (bio-oil and biochar) are also described. Bio-oils from all three biomass types contained mainly carboxylic acids (33–46 wt.%) and phenols (18–33 wt.%), hydroquinone (up to 5 wt.%), and a high amount of stearate (up to 26 wt.%). All of these compounds have high utility value. The resulting biochar can probably be applied, after activation using CO₂, as a sorbent. In conclusion, under energy-efficient conditions (end temperature max. 500 °C), Ru/Al₂O₃-catalyzed pyrolysis of biomass provides syngas or hydrogen-rich gas and usable by-products. It should be emphasized that the maximum theoretical H₂ production from biomass is 60–70 g H₂/kg biomass. This limit value could negatively affect the technological development of the process. Full article

Efficient coalbed methane (CBM) recovery combined with carbon dioxide (CO₂) sequestration is a promising strategy for sustainable energy production and greenhouse gas mitigation. However, the molecular mechanisms controlling pressure-dependent CH₄ displacement by CO₂ in coal nanopores remain insufficiently understood. In this study, molecular dynamics simulations were conducted to investigate CO₂-driven CH₄ recovery in a slit-pore coal model under driving pressures of 15, 20, and 25 Mpa. The simulations quantitatively captured the competitive adsorption, diffusion, and migration behaviors of CH₄, CO₂, and water, providing insights into how pressure influences enhanced coalbed methane (ECBM) recovery at the nanoscale. The results show that as the pressure increases from 15 to 25 Mpa, the mean residence time of CH₄ on the coal surface decreases from 0.0104 ns to 0.0087 ns (a 16% reduction), reflecting accelerated molecular mobility. The CH₄–CO₂ radial distribution function peak height rises from 2.20 to 3.67, indicating strengthened competitive adsorption and interaction between the two gases. Correspondingly, the number of CO₂ molecules entering the CH₄ region grows from 214 to 268, demonstrating higher invasion efficiency at elevated pressures. These quantitative findings illustrate a clear shift from capillary-controlled desorption at low pressure to pressure-driven convection at higher pressures. The results provide molecular-level evidence for optimizing CO₂ injection pressure to improve CBM recovery efficiency and CO₂ storage capacity. Full article

The aim of this work was to investigate the evolution of the mechanical integrity of the selected offshore oil reservoir during its life cycle. The geomechanical stability of the reservoir formation, including the caprock and base rock, was investigated from the exploitation phase through waterflooding production to the final phase of enhanced oil recovery (EOR) with CO₂ injection. In this study, non-isothermal flow simulations were performed during the process of cold water and CO₂ injection into the oil reservoir as part of the secondary EOR method. The analysis of in situ stress was performed to improve quality of the geomechanical model. The continuous changes in elastic and thermal properties were taken into account. The stress–strain tensor was calculated to efficiently describe and analyze the geomechanical phenomena occurring in the reservoir as well as in the caprock and base rock. The integrity of the reservoir formation was then analyzed in detail with regard to potential reactivation or failure associated with plastic deformation. The consideration of poroelastic and thermoelastic effects made it possible to verify the development method of the selected oil reservoir with regard to water and CO₂ injection. The numerical method that was applied to describe the evolution of an offshore oil reservoir in the context of evaluating the geomechanical state has demonstrated its usefulness and effectiveness. Thermally induced stresses have been found to play a dominant role over poroelastic stresses in securing the geomechanical stability of the reservoir and the caprock during oil recovery enhanced by water and CO₂ injection. It was found that the injection of cold water or CO₂ in a supercritical state mostly affected horizontal stress components, and the change in vertical stress was negligible. The transition from the initial strike-slip regime to the normal faulting due to formation cooling was closely related to the observed failure zones in hybrid and tensile modes. It has been estimated that changes in the geomechanical state of the oil reservoir can increase the formation permeability by sixteen times (fracture reactivation) to as much as thirty-five times (tensile failure). Despite these events, the integrity of the overburden was maintained in the simulations, demonstrating the safety of enhanced oil recovery with CO₂ injection (EOR-CO₂) in the selected offshore oil reservoir. Full article

Blue hydrogen technology, generated from natural gas through carbon capture and storage (CCS) technology, is a promising solution to mitigate greenhouse gas emissions and meet the growing demand for clean energy. To improve the sustainability of blue hydrogen, it is crucial to explore alternative feedstocks, production methods, and improve the efficiency and economics of carbon capture, storage, and utilization strategies. Two established technologies for hydrogen synthesis are Steam Methane Reforming (SMR) and Autothermal Reforming (ATR). The choice between SMR and ATR depends on project specifics, including the infrastructure, energy availability, environmental goals, and economic considerations. ATR-based facilities typically generate hydrogen at a lower cost than SMR-based facilities, except in cases where electricity prices are elevated or the facility has reduced capacity. Both SMR and ATR are methods used for hydrogen production from methane, but ATR offers an advantage in minimizing CO₂ emissions per unit of hydrogen generated due to its enhanced energy efficiency and unique process characteristics. ATR provides enhanced utility and flexibility regarding energy sources due to its autothermal characteristics, potentially facilitating integration with renewable energy sources. However, SMR is easier to run but may lack flexibility compared to ATR, necessitating meticulous management. Capital expenditures for SMR and ATR hydrogen reactors are similar at the lower end of the capacity spectrum, but when plant capacity exceeds this threshold, the capital costs of SMR-based hydrogen production surpass those of ATR-based facilities. The less profitably scaled-up SMR relative to the ATR reactor contributes to the cost disparity. Additionally, individual train capacity constraints for SMR, CO₂ removal units, and PSA units increase the expenses of the SMR-based hydrogen facility significantly. Full article

Geological Carbon Sequestration (GCS) plays a crucial role in addressing climate change, particularly in oil and gas development. Understanding the reaction of supercritical CO₂ under in situ conditions and its effects on minerals is essential for advancing GCS technology. This study investigates the reaction mechanisms of feldspar (potassium and sodium feldspar) and clay minerals (chlorite, illite, montmorillonite, kaolinite) in CO₂ environments. The impacts on mineral crystal structures, morphologies, and elemental compositions were analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), and ion concentration measurements (ICP-OES and ICP-MS). The results show that feldspar minerals exhibit lower reaction rates, with sodium feldspar dissolving faster than potassium feldspar, due to the higher solubility of sodium ions in acidic conditions. Chlorite showed significant crystal structure damage after 30 days, while montmorillonite underwent both dissolution and precipitation, influenced by interlayer cation dissociation. Kaolinite exhibited minimal reaction, primarily showing localized dissolution. Additionally, the formation of siderite (FeCO₃) was observed as Fe²⁺ substituted for Ca²⁺ in CaCO₃, highlighting the role of iron-bearing carbonates in CO₂ interactions. The study provides insights into the factors influencing mineral reactivity, including mineral structure, ion exchange capacity, and solubility, and suggests that chlorite, montmorillonite, and illite are more reactive under reservoir conditions, while kaolinite shows higher resistance to CO₂-induced reactions. These findings offer valuable data for optimizing GCS technologies and predicting long-term sequestration outcomes. Full article

The effectiveness of periodate-assisted photocatalysis in removing the cationic dye Safranin O (SO) was evaluated using a UV/TiO₂/IO₄⁻ process operated at room temperature under near-neutral pH conditions. Under base conditions ([IO₄⁻] = 0.15 mM, [TiO₂] = 0.4 g/L, [SO] = 10 mg/L), the ternary system achieved a pseudo-first-order rate constant of 0.6212 min⁻¹, outperforming the UV/TiO₂ and UV/IO₄⁻ processes by approximately 21- and 29-fold, respectively. This yielded a synergy ratio of about 12 compared to the sum of the binary processes. Targeted quenching experiments revealed the operative pathways. Strong inhibition by ascorbic acid and phenol indicates that interfacial holes and ^•OH are key oxidants. Methanol caused a moderate slowdown, consistent with ^•OH and hole scavenging. Benzoquinone and oxalate suppressed removal by intercepting the electron and O₂^•− pathways, respectively. Dichromate markedly inhibited the process via optical screening and competition for electrons. Azide had little effect, suggesting a minor role for singlet oxygen. Matrix studies showed progressively slower kinetics from deionized water to mineral water to seawater. This was due to halides, sulfate, alkalinity, and TiO₂ aggregation driven by ionic strength. Additional tests confirmed that the dominant modulators of performance were humic acid (site fouling and light screening), chloride and sulfate (radical speciation and surface effects), nitrite (near-diffusion radical quenching), and bicarbonate at pH 8.3 (conversion of ^•OH to CO₃^•−). Nonionic surfactants (Tween 80, Triton X-100) also depressed SO removal through micellar sequestration and competitive adsorption on TiO₂. The study confirms the potential of UV/TiO₂/IO₄⁻ as a tunable AOP capable of delivering rapid and reliable dye degradation under a wide range of water quality conditions. The mechanistic mapping unifies two roles for IO₄⁻, an electron acceptor that inhibits recombination and a photochemical precursor of iodine centered and ^•OH radicals and connect these roles to the observed synergy and to the trend across deionized water, mineral water, and seawater. The scavenger outcomes assign the main oxidant flux to holes and ^•OH radicals with a contributory electron or O₂^•− branch from IO₄⁻ reduction. Full article

Agroforestry is a land use system that has recently been recognised as a strategic tool for greenhouse gas mitigation and as an integrated approach to sustainable land use due to its environmental benefits. Hence, information on its net carbon sequestration potential is crucial for future land use planning and sustainable development. This paper aims to estimate net emissions and removals from silvopastoral and silvoarable systems by quantifying their areas across the EU27, the UK, and Switzerland, utilising the Land-Use-based Integrated Sustainability Assessment land cover map and Copernicus high-resolution layers. The analysis identified a total of 9.2 Mha of silvopastoral and silvoarable areas across the study area, comprising approximately 6 Mha and 3.2 Mha, respectively, mainly clustered around the Mediterranean biogeographical region. Collectively, these land use systems could remove approximately 81.7 Mt of CO₂ eq yr⁻¹ while emitting roughly 49.9 Mt CO₂ eq yr⁻¹, resulting in a net removal of 31.8 Mt of CO₂ eq yr⁻¹. From a global perspective, the EU27 reported 3180.2 Mt of CO₂ eq emissions in 2018, with the land use, land use change and forestry (LULUCF) sector acting as a net sink, removing 260.8 Mt CO₂ eq, equivalent to −8.2% of total emissions. Agroforestry, when integrated within the agriculture sector, could further enhance its GHG mitigation, potentially offsetting the sector’s emissions by 54%. Additionally, expanding agroforestry systems on 30% of the identified target areas would sequester up to 49 Mt of CO₂ eq yr⁻¹ more and result in planting 1.7 billion trees more. These findings highlight the positive role of agroforestry systems in contributing to the EU’s 2030 emission reduction and tree planting targets and emphasise the need for integrated management approaches to enhance and maximise their mitigation potential. Full article

This article addresses the storage of carbon dioxide [CO₂] in underground geological formations. It presents the results of a preliminary assessment of the feasibility of sequestering CO₂ in Cambrian aquifer units located within the Polish Exclusive Economic Zone of the Baltic Sea. The northern segment of a structure within the Rozewie tectonic block was selected as the research and test site. The aim was to determine the sequestration capacity and select optimal locations for injection wells, taking into account storage safety. The results and conclusions are based on numerical simulations of CO₂ injection and plume migration within a brine-filled structure using Petromod software v. 2024. A geological model of the site was developed representing the spatial distribution of petrophysical parameters (porosity and permeability) of the reservoir and sealing horizons. Fault zones were also mapped and parameterised in order to evaluate the structural integrity and identify potential migration barriers for the injected gas. An initial assessment assumed the possibility of injecting 100 Mt of CO₂ into the analyzed structure over a 30-year period using ten wells. However, simulation results based on the current state of geological characterization demonstrated that injection performance may vary considerably between individual wells. Wells situated within zones of highest reservoir capacity were estimated to sustain injection rates of 6–7 Mt of CO₂ over 30 years, implying that a greater number of injection wells would be required to accommodate the target storage amount. Fault seal capacity was evaluated using an algorithm based on the Shale Gouge Ratio (SGR) criterion, which enabled the assessment of fault permeability and revealed potential risks of CO₂ leakage. Numerical simulations further facilitated the estimation of the reservoir’s storage potential and the optimization of injection well placement, considering both injection efficiency and the risk associated with CO₂ migration and leakage. Full article

With increasing attention paid to the development of natural gas hydrates, various mining methods have been studied. CO₂-CH₄ hydrate replacement has become one of the key research topics in the field of natural gas hydrate mining because it can overcome the disadvantage of traditional mining methods that easily lead to reservoir collapse and realize CO₂ sequestration while extracting CH₄. However, complex heat and mass transfer, as well as fluid migration, are involved in CO₂-CH₄ hydrate in situ replacement, and this method has the drawbacks of slower reaction rates and a lower replacement efficiency compared to traditional methods. Therefore, a substantial amount of experimental and simulation research is still needed to advance this method. This paper reviews the current research on CH₄ recovery from CH₄ hydrate by CO₂ replacement. The main CO₂-CH₄ hydrate replacement mechanisms are summarized according to whether the hydrate cage structure is disrupted. Numerical simulation studies based on the above replacement mechanisms are introduced and compared in detail. The effects of various replacement methods, such as soaking replacement and dynamic replacement, as well as factors including the presence of initial water, reservoir permeability, temperature, and pressure on the replacement reaction, are summarized. Additionally, existing pore-scale replacement studies are reviewed, highlighting the necessity of pore-scale research on CO₂-CH₄ hydrate replacement reactions, pointing out the shortcomings of current pore-scale studies, and proposing suggestions for future research directions. This work provides a reference for the development of the CO₂-CH₄ hydrate replacement method and the realization of its industrial applications. Full article