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Journal articleQusty H, Ata F, Fennell P, et al., 2026,
Density and carbon dioxide solubility in aqueous solutions of potassium glycinate
, Fluid Phase Equilibria, Vol: 607, ISSN: 0378-3812We report measurements of the solubility of CO<inf>2</inf> in aqueous potassium glycinate and of the density of the solution with and without CO<inf>2</inf> loading. The CO<inf>2</inf> solubility was measured with a bespoke static-synthetic vapour liquid equilibrium (VLE) apparatus, while densities were measured with a high-pressure vibrating-tube densimeter. The VLE apparatus was validated by means of measuring the solubility of CO<inf>2</inf> in a 7 mol·kg<sup>-1</sup> aqueous ethanolamine solution, and the results were in good agreement with the literature. Three molalities of aqueous potassium glycinate were studied: (1, 2 and 3) mol·kg<sup>-1</sup>. The CO<inf>2</inf> solubility measurements were made at temperatures between (313.15 and 393.15) K with pressures up to 0.65 MPa, while the density was measured at temperatures between (298.15 and 393.15) K with pressures up to 10 MPa.
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Journal articleEdwards P, Leal da Silva WR, Fennell P, et al., 2026,
Strength performance and environmental assessment of Portland clinker
, Cement and Concrete Research, Vol: 205, ISSN: 0008-8846Alite influences both the early-age strength development and environmental footprint of concrete. However, the link between the alite content in clinker, strength development in concrete, and its carbon footprint remains overlooked in life cycle assessment. We study CEM I mortars containing clinkers with 5–85 wt% alite, combining thermodynamic modelling with a compressive strength prediction model based on the combined water fraction. Our model predicts that mortars made from high alite clinkers have 29% higher 28-day compressive strengths than that of low alite clinkers, at equivalent clinker and water contents. However, higher alite clinkers increase the CO<inf>2</inf>-eq. emissions of mortars by up to 19% compared with lower alite clinkers. In general, increasing alite content in clinker reduces CO<inf>2</inf>-eq. emissions per unit of strength gained in mortar. Therefore, the carbon footprint of concrete can be reduced by optimising both the alite content in clinker and concrete mix design.
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Journal articlePini R, Petit C, Danaci D, et al., 2026,
CO₂ capture by adsorption: research progress and technology demonstration
, International Journal of Greenhouse Gas Control, Vol: 153, ISSN: 1750-5836Adsorption is one of the main technologies proposed for CO₂ capture from industrial emitters. Although adsorption has been demonstrated at scale for other gas separations, its application to CO₂ capture remains an active area of research and field demonstration, owing to the complexity of feed streams (e.g., CO2 content, impurities) and the need to balance several process key performance indicators (e.g., purity and recovery of CO2 product). In this work, we take stock of the field’s progress, considering both research findings and demonstrations projects reported to date. We critically review the most relevant adsorption processes for different feed streams, depending on their composition, and highlight both established and emerging approaches for process modelling, design and optimisation. Importantly, we compile for the first time a traceable list of pilot- and full-scale CO₂ capture demonstration projects worldwide. We analyse the key technical challenges facing the field and identify priority areas for future research. Our report underscores the substantial body of knowledge accumulated on adsorption-based CO₂ capture processes over the years, their technical viability, and potential pathways toward commercial deployment.
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Journal articleHarris C, Krevor S, Muggeridge AH, et al., 2026,
Unstable Drainage Dynamics During Multiphase Flow Across Capillary Heterogeneities
, Geophysical Research Letters, Vol: 53, ISSN: 0094-8276We use novel, fast 4D Synchrotron X-ray imaging with large field-of-view to reveal pore- and macro-scale drainage dynamics during gas–brine flow through a layered sandstone rock sample. We show that a single centimeter-scale layer, similar in pore size distribution to the surrounding rock but with reduced connectivity, temporarily inhibits, and redirects gas flow, acting as a capillary barrier. Subtle variations in gas invasion upstream of the barrier lead to different downstream migration pathways over repeated experiments, resulting in unstable and unpredictable drainage behavior, with breakthrough times varying by up to a factor of four. The results show that heterogeneity in pore-scale connectivity can amplify variability in macroscopic flow, challenging deterministic assumptions in existing continuum models. By linking structural heterogeneity to flow instability, this work underscores the need for probabilistic modeling approaches in multiphase flow and highlights broader implications for managing fluid transport in natural and engineered porous systems.
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Journal articleAi L, Trusler JPM, 2026,
Experimental study of hydrogen-brine interfacial tension: Implications for natural hydrogen production
, International Journal of Hydrogen Energy, Vol: 224, Pages: 154442-154442, ISSN: 0360-3199 -
Journal articleDarraj N, Manoorkar S, Spurin C, et al., 2026,
Impact of pore-scale heterogeneity on continuum-scale multiphase flow properties: Insights from Indiana limestone
, International Journal of Greenhouse Gas Control, Vol: 151, ISSN: 1750-5836Microscale heterogeneity in porous media can influence larger-scale multiphase flow behaviour, particularly in the context of CO<inf>2</inf> storage. We conducted a multiphase steady-state flooding experiments on Indiana limestone, a carbonate with millimetre-scale heterogeneity, at two flow rates with capillary numbers of N<inf>c</inf> = 5 × 10<sup>−8</sup>and 1 × 10<sup>−7</sup>. Micro-CT at a 4.9 µm resolution was used to image nitrogen–brine displacement: the analysis included the whole sample and six representative sub-volumes from distinct regions.The analysis shows that doubling the capillary number produced a more homogeneous saturation profile, reflecting the greater influence of viscous forces even within a predominantly capillary-controlled regime. Moreover, the relative permeabilities shifted upward and to higher brine saturation with decreasing flow rate; this indicated that the non-wetting phase benefits from enhanced connectivity through preferential pathways. As the flow rate increases, however, viscous forces begin to override local capillary entry barriers, enabling the non-wetting phase to invade smaller and previously uninvaded pores. The sub-volume analysis showed two distinct regions with different entry pressures: the regions with higher entry pressure exhibit a higher gas invasion at the higher flow rate, whereas low capillary entry pressure regions showed minimal change.These observations show that modest increases in capillary number can change relative permeability, saturation, and trapping. This underlines the need to represent capillary heterogeneity when upscaling flow properties for reservoir-scale simulation of subsurface CO₂ storage. Relative permeability models that neglect sub-grid variability may bias simulated plume migration and trapping efficiency, and therefore the inferred storage performance.
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Journal articleBecattini V, Gazzani M, Pini R, et al., 2026,
Marco Mazzotti─Advancing Separation Science through Education, Innovation, and Real-World Impact
, Industrial and Engineering Chemistry Research, Vol: 65, Pages: 2979-2983, ISSN: 0888-5885 -
Journal articleSpreng TL, Danaci D, Ram PD, et al., 2026,
Amine-Appended Hyper-Crosslinked Polymers for Direct Air Capture of CO2.
, ACS Sustain Chem Eng, Vol: 14, Pages: 1834-1846, ISSN: 2168-0485Capturing CO2 from the ambient atmosphere is a promising method to reduce the impact of climate change. Fast deployment and scale-up of adsorption-based direct air capture (DAC) technologies are needed to meet the IPCC target and rely, in part, on the development of efficient and scalable low-cost adsorbents. While a benchmark DAC adsorbent, the polymeric resin Lewatit VP OC 1065, has been established, the reasons behind its performance and the potential for further optimization remain largely unknown. Indeed, a fundamental understanding of the relationship between adsorbent pore structure, chemistry, and DAC performance, both equilibrium and kinetics, has yet to be formulated. Here, we have built on the chemistry of Lewatit and synthesized a hyper-crosslinked polymer (HCP) by grafting a microporous chlorine-functionalized support with diethylenetriamine. We produced four different adsorbents by varying the polymerization duration between 10 min and 19 h to assess the impact of pore structure on CO2 uptake at 400 ppm. Reduced degrees of polymerization (i.e., shorter polymerization durations) resulted in higher accessible micropore volume and consequentially increased CO2 uptake and amine efficiency. The best sample achieved an equilibrium uptake of 0.43 mmol/g (400 ppm of CO2, 298 K), which is about half that of the benchmark adsorbent Lewatit VP OC 1065. We have then assessed the CO2 sorption kinetics of this sample (grain size of 24-74 μm) at 400 ppm and 303 K using a gravimetric technique and have compared the results to those of other amine-grafted polymeric adsorbents. We measured a lower bound linear driving force constant (k LDF) of 0.0120 ± 0.0004 s-1. This value is 5.5 times faster than that of the benchmark adsorbent Lewatit VP OC 1065 with the same grain size of 24-74 μm, highlighting the importance of macropore diffusion in addition to the CO2 reaction kinetics. This study shows how synthesis operating conditions alter the pore structures an
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Journal articleGhaedi H, Fu J, Meng X, et al., 2026,
Iono non-hydrothermal (INH) method for synthesis of highly ordered mesoporous silica materials
, Chemical Engineering Journal, Vol: 528, ISSN: 1385-8947Highly ordered mesoporous silica materials (HOMMs) are widely valued for applications in catalysis, adsorption, and energy storage, but their traditional synthesis suffers from lengthy hydrothermal aging, high-temperature calcination, toxic swelling agents, and irreversible loss of the expensive Pluronic P123 template. Herein, we introduce a novel Iono Non-Hydrothermal (INH) method that completely eliminates both hydrothermal treatment and calcination. Green deep eutectic solvents (DESs) are employed in a multifunctional role as reaction medium, swelling agent, and low-temperature (120 °C) de-templating agent. The optimized ternary DES enables efficient template removal while preserving abundant surface silanol groups. The resulting HOMMs exhibit high surface area (up to 777 m<sup>2</sup>/g), uniform pore size (∼7.8 nm), and excellent structural order comparable to conventionally synthesized SBA-15. The influence of synthesis pH (adjusted by NH₄OH) and DES composition on pore structure and hydrothermal stability is systematically investigated, revealing that higher condensation pH significantly enhances resistance to boiling-water degradation. Importantly, simple ethyl acetate extraction of the post-synthesis filtrate allows recovery of P123 together with the DESs, establishing a near-closed material loop. A preliminary techno-economic analysis demonstrates 81–87 % material cost reduction, 50–67 % lower energy consumption, and > 32 % higher throughput compared to the conventional hydrothermal-calcination route. The INH strategy thus offers a sustainable, scalable pathway for producing high-performance mesoporous silica materials with substantially reduced environmental impact and production cost.
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Journal articleWang K, Zhao P, Zhou T, et al., 2026,
High-temperature CO2 capture and in-situ conversion over bifunctional Na2ZrO3 self-catalyst/sorbent for circular CO production
, Chemical Engineering Journal, Vol: 528, ISSN: 1385-8947CO<inf>2</inf> capture and utilization to produce value-added fuels and chemicals offers a promising avenue to assist in the mitigation of the global warming crisis. However, there are economic challenges for the regeneration of some sorbents used in CO<inf>2</inf> capture, owing to sorbent sintering and high energy requirements, while direct conversion processes are hindered by the lack of cost-effective, efficient, selective, and stable catalysts. We demonstrate the use of sodium zirconate-looping (NaL) with the reverse-Boudouard (RB) reaction enabling high-temperature CO<inf>2</inf> capture and in-situ CO<inf>2</inf> conversion operating in a single isothermal reactor operating at 800 °C. While employing a mild combustion synthesis method, the dual-function material Na<inf>2</inf>ZrO<inf>3</inf> exhibited a high and stable CO<inf>2</inf> uptake capacity of 4.9 mmol CO<inf>2</inf>/g without the use of Ni catalysts. This is due to its fine particle size, macroporous structure, and well-dispersed ZrO<inf>2</inf> stabilizer within the Na<inf>2</inf>O matrix. The resulting Na<inf>2</inf>CO<inf>3</inf>-ZrO<inf>2</inf> and regenerated Na<inf>2</inf>ZrO<inf>3</inf> phases (as synergistic self-catalysts) mixed with renewable and cost-effective biochar (as a reductant) facilitated exceptional in-situ CO<inf>2</inf> conversion efficiency (∼90 %), as well as high CO selectivity (approaching 100 %), and relative stability (∼80 %) even after multiple cycles. Importantly, theoretical calculations aligned with mechanistic studies revealed that the activation energy barriers at two specific oxygen sites for the monatomic C-assisted CO<inf>2</inf> dissociation/gasification were lower than the desorption energy of CO<inf>2</inf> on the Na<inf>2</inf
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Journal articleRestelli F, Jiao F, Norris B, et al., 2026,
Dynamic simulation of a liquefied hydrogen export terminal
, Energy, Vol: 342, ISSN: 0360-5442At prospective liquid hydrogen (LH<inf>2</inf>) export terminals, managing boil-off gas (BOG) presents a significant challenge that has not been adequately explored in the literature. This work is a case study examining the management of BOG evolved during storage and carrier loading at an export terminal, carried out using detailed dynamic simulations. The considered terminal operates with a LH<inf>2</inf> production rate of 450 t/d, and a carrier capacity of 160000 m<sup>3</sup>. The normal operation cycle spans a period of 28 days, during which all the generated BOG is recovered. The estimated levelized cost for terminal storage and shipment is 2.77 USD/kg, underlining the need for further research to reduce costs and enhance the economic viability of LH<inf>2</inf> export. A sensitivity analysis indicates that the production rate primarily affects the duration of the normal operation cycle and, consequently, shipping frequency, while feed pressure and ortho-para hydrogen composition significantly influence total BOG generation.
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Journal articleChen Q, Trusler JPM, 2025,
Olivine dissolution kinetics at elevated temperatures and pressures
, Chemical Engineering Journal, Vol: 525, ISSN: 1385-8947Experimental and modelling studies of the dissolution kinetics and surface chemistry of olivine in CO2-saturated water at elevated temperatures and CO2 pressures are reported. The apparent initial dissolution rates of olivine are reported at temperatures between 373 and 473 K and at pressures between 7.7 and 15.6 MPa. The influence of mass transfer effects on olivine dissolution and the formation of passivation layers were studied, and the minimum stirring speed at which mass transfer resistance was effectively eliminated was determined. The optimum temperature for olivine dissolution in the long term was determined to be approximately 423 K. This study provides the first data for olivine dissolution rates at temperatures above 423 K. The initial olivine dissolution rates did not show a monotonic increasing trend with the increase of temperature due to the formation of various passivation layers on the olivine particle surfaces at different temperatures. A simple model, dependent upon temperature and the activity of H+, was developed to represent the experimental data. This model is generally applicable under similar temperature and pressure conditions, and when the same type of passivation layer is present. Based on the proposed model, the PHREEQC geochemical simulator was used to predict the saturation indices of Fe2O3 (hematite), FeO(OH) (goethite), Fe(OH)3 (ferric hydroxide) and SiO2 (both quartz and amorphous silica). The pH and elemental concentrations were also predicted and these calculations served to partially rationalize the experimental results.
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Journal articleChristopher B, Alaa AK, Heleen DC, et al., 2025,
Defining ‘abated’ fossil fuel and industrial process emissions
, Energy and Climate Change, Vol: 6, ISSN: 2666-2787There is scientific consensus that limiting warming in line with the Paris Agreement goals requires reaching net zero CO2 emissions by mid-century and net negative emissions thereafter. Because of the entrenchment of current fossil fuel energy and feedstock demand estimated in almost all global modelled scenarios, 'abated' fossil fuel and industrial process and product use (IPPU) CO2 emissions, using carbon capture and storage (CCS) technologies to perform carbon management, are likely to be part of any transition. In addition to fossil fuel combustion, this will be primarily in cement & lime kilns, chemical production, and possibly waste incineration and iron and steel making, in processes producing maximally concentrated CO2 waste streams. Abated fossil fuel and IPPU CO2 emissions in the context of recent commitments, however, requires consideration of capture rates for fuel processing and end-use, permanence of storage, reduction of upstream production and end-use fugitive methane, and sufficient means to sequester residual emissions. Based on an assessment of evolving CCS technologies in existing sectors and jurisdictions, criteria are proposed for defining a benchmark for 'abated' fossil fuel and IPPU emissions as where near 100 % GHG abatement is to be eventually achieved, with N2O and fluorinated gases considered separately. This can be accomplished through: 1) CO2 capture rates of more than or equal to 95 % of CO2 emitted; 2) permanent storage of captured emissions; 3) reducing upstream and end-use fugitive methane emissions to <0.5 % and towards 0.2 % of gas production & an equivalent for coal; and 4) counterbalancing remaining emissions using permanent carbon dioxide removal. Application of these criteria to just steel and cement yields estimates of more than or equal to 1.37 Gt CO2 per year reductions after all other reasonable and lower cost actions are taken. At the same time, we acknowledge the value of capture rates below 95 %, so as long t
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Journal articleWenck N, Muggeridge A, Jackson S, et al., 2025,
The impact of capillary heterogeneity on CO2 plume migration at the Endurance CO2 storage site in the UK
, Geoenergy, Vol: 3Predictive modelling of subsurface CO<inf>2</inf> flow is used for optimzing the design of geological CO<inf>2</inf> storage projects e.g. with respect to mass stored and long-term security. However several field scale projects have reported plume dynamics that do not match numerical predictions. Previous work has indicated that upscaling capillary heterogeneity results in different plume dynamics in synthetic 2D cross-sections and at early times (<0.2 PV injected). Here we extend the workflow to 3D and analyse the impacts of longer-term flow behaviour in an industrial scale geological carbon storage site with multi-point CO<inf>2</inf> injection, structural relief and realistic flow rates. The models reveal that capillary heterogeneity in horizontally layered lithologies enhances the formation of preferential flow paths, increases swept volumes and areas, and reduces vertical migration speed near the injectors, all of which improve storage efficiency. At distances far from the injectors, the plume travels faster as a result of the heterogeneity. The results also show that simulations in 3D have qualitatively distinct results from those in 2D due to the increase in flow pathways.
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Journal articleBahzad H, Leonzio G, Soltani SM, et al., 2025,
Techno-economic analyses of a novel hydrogen production process<i> via</i> chemical looping water splitting, integrated with sorption enhanced water gas shift
, INTERNATIONAL JOURNAL OF HYDROGEN ENERGY, Vol: 188, ISSN: 0360-3199 -
Journal articleAboulrous AA, Darraj NM, Cunsolo V, et al., 2025,
Effect of imidazolium-based ionic liquid on CO2 sequestration: a study on solubility, interfacial properties, and X-ray imaging in water-wet formations
, Journal of Molecular Liquids, Vol: 435, ISSN: 0167-7322The efficiency of geological CO₂ sequestration is often limited by low CO₂ solubility, which poses challenges for long-term storage stability. This study addresses these limitations by exploring the potential of 1-butyl-3-methylimidazolium bromide (BMIM-Br) to enhance CO₂ storage in water-wet subsurface formations. BMIM-Br was synthesized via a microwave-assisted method and the structure was confirmed using different spectroscopic methods including Fourier Transform Infrared Spectroscopy (FTIR), and Proton Nuclear Magnetic Resonance (1H NMR) analysis.Under conditions of 3 MPa and 323.15 K, the solubility of CO₂ in a 5 wt% BMIM-Br solution was more than double the solubility in pure water. At 0.3 MPa, the interfacial tension (IFT) between CO₂ and the BMIM-Br solution decreased from 36.3 mN/m to 32.9 mN/m at 293.15 and 323.15 K, respectively compared to the pure water values 69.9 mN/m and 63.8 mN/m respectively at the same conditions. When CO2 was injected into a Bentheimer sandstone rock sample fully saturated with the aqueous phase. There was a significant increase in CO₂ saturation (SCO2), rising from 0.58 with pure water to 0.72 with BMIM-Br. The lowered interfacial tension allows more of the pore space to be accessed at the same imposed capillary pressure. When the aqueous phase was injected to displace CO2, the residual saturation was 0.21 with pure water, but only 0.16 for the BMIM-Br solution. This is likely a consequence of increased dissolution of CO2 in BMIM-Br. These results suggest that BMIM-Br significantly improves CO₂ solubility and injectivity by reducing interfacial tension. Its overall impact points to a promising strategy for optimizing CO₂ sequestration in subsurface formations.
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Journal articleSuleman MY, Judah HL, Bexis P, et al., 2025,
The acetate anion promotes hydrolysis of poly(ethylene terephthalate) in ionic liquid-water mixtures
, Green Chemistry, Vol: 27, Pages: 11475-11490, ISSN: 1463-9262A circular plastic economy reduces raw material consumption and discourages pollution. Chemical recycling upgrades the quality of recyclate and is a complementary approach to thermomechanical recycling of plastic waste. This study investigated the use of aprotic and protic ionic liquids (ILs) as solvents for chemical recycling by the hydrolysis of the most common polyester plastic, poly(ethylene terephthalate) (PET). Combinations of three types of cations (aprotic 1-alkyl-3-methylimidazolium, protic 1-methylimidazolium and protic 1,5-biazocyclo-[4.3.0]non-5-enium) combined with a range of anions (acetate, chloride, methanesulfonate, hydrogen sulfate, methyl sulfate, trifluoromethanesulfonate and chlorozincate) were used to hydrolyse PET in the presence of 15 wt% water as the co-solvent and reagent. PET conversion under the screening conditions (180 °C, 3 h, 5% PET loading) varied between 1 and 100%, with ILs containing the acetate anion enabling >97% PET conversion irrespective of the cation. Acidification with aqueous HCl recovered crude crystallised terephthalic acid (TPA). Significant crude yields (46–93%) were only observed for the acetate ILs. The purity of the crude TPA was 34–98%, with 1-ethy-3-methylimidazolium acetate, [C2C1im][OAc], and 1-methylimidazolium acetate, [C1Him][OAc], yielding more and purer TPA than 1,5-biazocyclo-[4.3.0]non-5-enium acetate, [DBNH][OAc]. TPA solubility, PET conversion and TPA yield generally correlated well with increasing pKa and higher hydrogen bond acceptor strength of the IL anion, suggesting that the depolymerisation mechanism in the acetate IL water mixtures is base catalysed. The screening identifies aqueous mixtures of the (pseudo)-protic IL [C1Him][OAc] as promising catalytic solvent component for the chemical recycling of PET at an industrially feasible temperature, due to high isolated TPA yields and purity achieved at a low solvent cost ($1.74–2.15 per kg). However, an effective separation a
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Journal articleGasós A, Pini R, Becattini V, et al., 2025,
Correction: Carbon footprint of oil produced through enhanced oil recovery using carbon dioxide directly captured from air
, Energy and Environmental Science, Vol: 18, Pages: 8088-8088, ISSN: 1754-5692Correction for ‘Carbon footprint of oil produced through enhanced oil recovery using carbon dioxide directly captured from air’ by Antonio Gasós et al., Energy Environ. Sci., 2025, https://doi.org/10.1039/d5ee01752a.
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Conference paperCunsolo V, Darraj N, Catherine S, et al., 2025,
Characterising Rock Heterogeneity from an Offshore Dutch CO2 Storage Site
, World CCUS Conference 2025 -
Journal articleGasos A, Pini R, Becattini V, et al., 2025,
Carbon footprint of oil produced through enhanced oil recovery using carbon dioxide directly captured from air
, Energy and Environmental Science, Vol: 18, Pages: 7440-7446, ISSN: 1754-5692Some argue that using CO2 from direct air capture (DAC) in enhanced oil recovery (CO2-EOR) can produce carbon-neutral oil by permanently storing more CO2 than is emitted when using the extracted fossil fuels. However, existing analyses often provide case-specific insights based on short-term operations without considering the full life cycle of reservoir exploitation, including primary, secondary, and tertiary (EOR) recovery phases. Here, we present a general, top-down approach based on mass and volume conservation to assess the potential carbon footprint of oil production, applicable to different temporal perspectives of reservoir exploitation. Supported by field data from 16 EOR projects, our analysis shows that 30% of projects appear carbon-neutral when EOR is considered in isolation, but they all become significantly carbon-positive when the full reservoir lifetime is considered. The volume of emitted CO2 exceeds the pore space freed for storage by at least a factor of three, making carbon-neutral oil physically unattainable in conventional reservoirs. The favorable conditions for low-carbon oil production during CO2-EOR exist solely because of extensive prior oil extraction and water injection, and only residual oil zones may truly offer potential for carbon-neutral oil due to their low oil saturation and lack of legacy emissions. While omitting legacy emissions from previously depleted fields may be justifiable and may enable claims of carbon neutrality during the EOR phase, newly developed fields, i.e., developed now or in the future, should be held accountable for the full life-cycle emissions they generate. This necessitates clear and transparent accounting policy frameworks. Although CO2-EOR may reduce oil's carbon footprint, promoting it as a pathway to carbon-neutrality risks legitimizing continued fossil fuel production, ultimately undermining global climate targets.
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Journal articleDezashibi AHM, Hallett JP, Fennell PS, 2025,
Design and operation of a cost-effective reactor for large protic ionic liquid synthesis
, CHEMICAL ENGINEERING AND PROCESSING-PROCESS INTENSIFICATION, Vol: 213, ISSN: 0255-2701 -
Journal articleEluwah C, Fennell PS, 2025,
Novel onboard ammonia cracker for light-duty automotive fuel cell vehicles
, Energy Advances, ISSN: 2753-1457This work introduces an innovative onboard ammonia cracker module integrated with a 100-kW fuel cell system for light-duty automotive fuel cell vehicles. Utilizing a hollow fibre palladium membrane reactor (HFMR), two configurations are explored: a 3 × 3 simultaneous heating and cracking module and a 4 × 4 intermediate heating and cracking module. The 3 × 3 module, arranged in a serpentine configuration, exhibits superior performance with a calculated required volume of 8.9 liters, a total module area of 1.2 m2 and a process thermal efficiency of 93.5%. Each reactor in this module operates isothermally at an exit temperature of 475 °C, achieving ammonia conversion rates that increase from 15.8% in the first reactor (R1) to an impressive 99.99% in the final reactor (R8), facilitated by in situ hydrogen removal through the palladium membrane. The steady-state analysis was carried out using Aspen Plus Software, and validated against experimental data from existing literature. The results demonstrated a high degree of agreement, confirming the model's capability to accurately predict system performance. For transient analysis, Aspen Plus Dynamics was employed to assess the system's responsiveness to varying driving conditions. Utilizing the Hyundai Nexo fuel cell car as a case study, the worldwide harmonised light vehicle test procedure (WLTP) was simulated, to model realistic driving cycles, allowing for a rigorous interrogation of the transient performance of the on-board ammonia cracker. Overall, this research establishes a 3 × 3 simultaneous heating and cracking HFMR module as the optimal configuration for on-board ammonia cracking for hydrogen production in fuel-cell vehicles, highlighting its operational efficiency and potential contribution to sustainable transportation solutions. Future research should focus on optimizing heat management and temperature control within the HFMR module, as well as enhancing transient response characteri
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Journal articleKhan SN, Zhao M, Fennell PS, et al., 2025,
Construction of Highly Mesoporous Metal-Organic Frameworks via Green Metallic Solvents Assisted Route for Chemical CO<sub>2</sub> Fixation
, SMALL, Vol: 21, ISSN: 1613-6810- Cite
- Citations: 4
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Journal articleEckel A-ME, Rovelli A, Pini R, 2025,
Direct characterization of free solutal convection in porous rocks for CO₂ storage applications
, Environmental Science & Technology, Vol: 59, Pages: 4618-4630, ISSN: 0013-936XFree solutal convection refers to the mixing process induced and sustained by local density differences arising from solute dissolution. This process underpins the long-term storage of carbon dioxide (CO2) following its injection and dissolution in the formation brine of subsurface rock formations, such as saline aquifers. Direct experimental evidence of free solutal convection in porous rocks is to-date still lacking, leaving large uncertainties on the realized rate of CO2 dissolution and its contribution toward storage. Using an analogue solute–solvent pair and 4D X-ray computed tomography, we report direct observations of this mixing process in rock core samples, including sandstones and carbonates. The imagery is used to characterize the mixing structures that arise upon solute dissolution and to quantify differences between the rock types. Thus, we compute the temporal evolution of spatial moments of the concentration distribution to derive practical properties, such as the effective transport velocity of the solute plumes. Unlike previous studies on random bead packs, we observe that these measures do not scale well with core-scale rock properties (permeability, porosity, Rayleigh number) and are influenced by microscale rock characteristics (subcore and pore-scale heterogeneities). The latter may need consideration when evaluating the CO2 storage potential of candidate formations.
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Journal articleJaeggi A, Eckel A-M, Pini R, et al., 2025,
Exploring disordered packing of non-equant particles: Insights from computed tomography and Monte Carlo simulations
, POWDER TECHNOLOGY, Vol: 452, ISSN: 0032-5910 -
Journal articlePan Z, Trusler JPM, Jin Z, et al., 2025,
Interfacial property determination from dynamic pendant-drop characterizations
, Nature Protocols, Vol: 20, Pages: 363-386, ISSN: 1750-2799The properties of the interface between materials have practical implications in various fields, encompassing capillary action, foam and emulsion stability, adhesion properties of materials and mass and heat transfer processes. Studying the dynamics of interfaces is also fundamental for understanding intermolecular interactions, change of molecular conformations and molecular aggregations. Pendant-drop tensiometry and its extension, the oscillating drop method, are simple, versatile methods used to measure surface tension, interfacial tension and interfacial rheological properties. These methods can, however, generate unreliable results because of inadequate material preparation, an incorrect calibration method, inappropriate selection of data for analysis, neglect of optical influences or operating the system outside the linear viscoelastic regime. In addition, many studies fail to report accurate uncertainties. This protocol addresses all these critical points and provides detailed descriptions of some operation tips relating to purifying methods for different kinds of material, the time frame for analyzing measurement data, the correction method for optical effects, implementation of the oscillating method with a common programmable pump and remedies for some common problems encountered during the measurement. Examples of interfacial tension measurements for two- and three-phase systems, as well as interfacial dilational modulus measurements for N2 and surfactant solutions, are provided to illustrate procedural details and results. A single measurement takes minutes to hours to complete, while the entire protocol, including the leak test, cleaning, repeated measurements and data analysis, may take several days.
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Journal articleKurotori T, Zahasky C, Benson S, et al., 2025,
Direct observations of solute dispersion in rocks with distinct degree of sub-micron porosity
, Water Resources Research, Vol: 61, ISSN: 0043-1397The transport of chemical species in rocks is affected by their structural heterogeneity to yield a wide spectrum of local solute concentrations. To quantify such imperfect mixing, advanced methodologies are needed that augment the traditional breakthrough curve analysis by probing solute concentration within the fluids locally. Here, we demonstrate the application of asynchronous, multimodality imaging by X-ray computed tomography (XCT) and positron emission tomography (PET) to the study of passive tracer experiments in laboratory rock cores. The four-dimensional concentration maps measured by PET reveal specific signatures of the transport process, which we have quantified using fundamental measures of mixing and spreading. We observe that the extent of solute spreading correlate strongly with the strength of subcore-scale porosity heterogeneity measured by XCT, while dilution is enhanced in rocks containing substantial sub-micron porosity. We observe that the analysis of different metrics is necessary, as they can differ in their sensitivity to the strength and forms of heterogeneity. The multimodality imaging approach is uniquely suited to probe the fundamental difference between spreading and mixing in heterogeneous media. We propose that when multi-dimensional data is available, mixing and spreading can be independently quantified using the same metric. We also demonstrate that one-dimensional transport models have limited predictive ability toward the internal evolution of the solute concentration, when the model is solely calibrated against the effluent breakthrough curves. The data set generated in this study can be used to build realistic digital rock models and to benchmark transport simulations that account deterministically for rock property heterogeneity.
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Journal articleBrotto JDO, Danaci D, Fennell PS, et al., 2025,
Enhancing low-carbon iron and steel production with torrefied biomass
, BIOMASS & BIOENERGY, Vol: 193, ISSN: 0961-9534- Cite
- Citations: 1
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Journal articleAzzan H, Gmyrek K, Danaci D, et al., 2025,
Effective macropore diffusivity of carbon dioxide on binderless pellets of Y-type zeolites
, Adsorption, Vol: 31, ISSN: 0929-5607The adsorption kinetics of carbon dioxide (CO2) in three cationic forms of binderless pellets of Y-types zeolites (H-Y, Na-Y, and TMA exchanged Na-Y) are studied using the zero-length column (ZLC) technique. The measurements were carried out at 288.15 K, 298.15 K and 308.15 K using different flowrates and an initial CO2 partial pressure of 0.10 bar – conditions representative of post-combustion CO2 capture applications. The mass transport within the adsorbent pellets was described using a 1-D Fickian diffusion model accounting for intra- and inter-crystalline mass transport. For the latter, the parallel pore model formulation was used to explicitly account for the adsorbent’s macropore size distribution in estimating the volume-averaged diffusivity of the gas. Experiments carried out using different carrier gases, namely helium and nitrogen, were used (i) to determine that these systems are macropore diffusion limited and (ii) to simplify the parameter estimation to a single parameter - the macropore tortuosity. The latter (τ = 1.3 − 2.5) was in good agreement with independent measurements using MIP (τ ≈ 1.7). The associated diffusion coefficient, Demac, was found to vary due to differences in the materials’ macropore size distributions and overall porosity. Upon combining the parallel pore model formulation with the temperature dependencies for the pore diffusivities derived from molecular theories of gases, we predict Demac ∝ Tb with b = [0.78 − 0.88] depending on the macropore size distribution. Notably, for the range of temperature tested in this study, Demac varies approximately linearly with temperature (b ≈ 1)– in contrast to the commonly reported correlation of b = 1.75, which may be more appropriate for systems where molecular diffusion dominates and Knudsen diffusion is negligible. The binderless pellets of Y-type zeolites studied exhibit generally higher values for the effective macropore diffus
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Journal articleKaerger J, Valiullin R, Brandani S, et al., 2025,
Diffusion in nanoporous materials with special consideration of the measurement of determining parameters (IUPAC Technical Report)
, Pure and Applied Chemistry, Vol: 97, Pages: 1-89, ISSN: 0033-4545The random motion (the diffusion) of guest molecules in nanoporous host materials is key to their manifold technological applications and, simultaneously, a ubiquitous phenomenon in nature quite in general. Based on a specification of the different conditions under which molecular diffusion in nanoporous materials may occur and of the thus resulting relevant parameters, a survey of the various ways of the measurement of the determining parameters is given. Starting with a condensed introduction to the respective measuring principles, the survey notably includes a summary of the various parameters accessible by each individual technique, jointly with an overview of their strengths and weaknesses as well as of the respective ranges of observation. The presentation is complemented by basic relations of diffusion theory and molecular modeling in nanoporous materials, illustrating their significance for enhancing the informative value of each measuring technique and the added value attainable by their combination. By providing guidelines for the measurement and reporting of diffusion properties of chemical compounds in nanopores, the document aims to contribute to the clarification and standardization of the presentation, nomenclature, and methodology associated with the documentation of diffusion phenomena in nanoporous materials serving for catalytic, mass separation, and other relevant purposes.
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