CO2 Absorption Research Articles

The effects of counter ion on CO2 capture performance of amino acid salt solutions for direct air capture applications

The effects of counter ion on CO2 capture performance of amino acid salt solutions for direct air capture applications

A multi-approach study on CO2 absorption in packed beds: Theoretical, experimental, and CFD perspectives on gas phase pulsation

A multi-approach study on CO2 absorption in packed beds: Theoretical, experimental, and CFD perspectives on gas phase pulsation

ZIF-8 and ZIF-67 as catalysts for promoting carbon dioxide capture based on monoethanolamine solution

ZIF-8 and ZIF-67 as catalysts for promoting carbon dioxide capture based on monoethanolamine solution

Liquid structure of quaternary-ammonium ionic liquids-propanol mixtures as CO2 absorber: Role of fluctuation

Liquid structure of quaternary-ammonium ionic liquids-propanol mixtures as CO2 absorber: Role of fluctuation

Experimental investigation of CO2 and H2S absorption from real gas and foaming investigation of alkanolamine mixtures in T-shaped microchannel

Experimental investigation of CO2 and H2S absorption from real gas and foaming investigation of alkanolamine mixtures in T-shaped microchannel

Preparation, stability, and enhanced CO2 absorption and desorption of nanofluids: Review and perspectives

Preparation, stability, and enhanced CO2 absorption and desorption of nanofluids: Review and perspectives

A comparative analysis of the effect of amines on CO2 absorption of type III porous liquids

A comparative analysis of the effect of amines on CO2 absorption of type III porous liquids

Optimization strategies to improve the carbon sink capacity of C3 plants under the background of dual carbon strategy.

Optimization strategies to improve the carbon sink capacity of C3 plants under the background of dual carbon strategy.

Development of nanoemulsion CO2 absorbents in an impinging stream rotating packed bed reactor

Development of nanoemulsion CO2 absorbents in an impinging stream rotating packed bed reactor

Thermal oxidation degradation mechanism under the rust-catalyzed condition of CO2 absorbent monoethanolamine and the DFT analysis of pathway

Thermal oxidation degradation mechanism under the rust-catalyzed condition of CO2 absorbent monoethanolamine and the DFT analysis of pathway

Characteristics of Carbon Sink and the Influencing Factors in Ngoring Lake, Qinghai‐Tibet Plateau

AbstractContinuous annual carbon dioxide (CO2) flux, encompassing ice‐covered periods, has been monitored in Ngoring Lake, the largest freshwater lake on the Qinghai‐Tibet Plateau (QTP). By utilizing continuous eddy system data, the characteristics and mechanisms influencing CO2 flux at various temporal scales in the lake were investigated. Findings revealed that Ngoring Lake was predominantly acting as a carbon sink year‐round. The average annual CO2 sink value was maximum in 2016, about −1.46 g C m−2 d−1. There were two CO2 absorption peaks in spring and autumn, respectively. The multi‐year average monthly mean CO2 absorption peaks occurred in April (−1.70 g C m−2 d−1) and October (−1.75 g C m−2 d−1), respectively. These peaks were associated with the freeze‐thaw process and were caused by the mixing process due to water cooling. The continuous warming during the ice‐covered period led to a high‐water temperature, and the maximum value reached 6°C. In spring, mixing occurred upon ice melt, and the water temperature at 2 m depth decreased rapidly to 4°C because it was about 5°C higher than the air temperature. In autumn, cooling and mixing were induced by decreasing air and water temperatures alongside strong wind. These cooling processes facilitated significant CO2 absorption. The CO2 absorption process was controlled by wind speed, lake ice, lake mixing and stratification.

Mechanisms of CO2 Absorption in Amino Acid-Based Deep Eutectic Solvents: Insights from Molecular Dynamics and DFT Calculations.

This study explores the mechanisms of CO2 absorption in two amino acid-containing deep eutectic solvents (DESs) through molecular dynamics (MD) simulations and density functional theory (DFT) calculations. The MD simulations, which focus mainly on physical absorption, reveal that alanine-based DES (Ala DES) exhibits higher CO2 solubility than l-arginine-based DES (l-arg DES), attributed to stronger physical absorption. Furthermore, the hydrogen bond donor paired with the amino acids is identified as a critical factor for enhancing physical absorption efficiency. DFT calculations, which account for chemical absorption, investigate two reaction pathways: single-molecule reactions involving intramolecular proton transfer and two-molecule reactions involving intermolecular proton exchange. While Ala DES does not exhibit spontaneous chemical absorption, l-arg DES demonstrates such reactions, leading to the formation of carbamic acid or carbamate (ΔG < 0), indicative of CO2 capture through chemical interactions. Consequently, Ala DES primarily relies on physical absorption, whereas l-arg DES utilizes multiple reactive sites for chemical absorption. These results are consistent with experimental findings, which show that l-arg DES achieves higher CO2 solubility under atmospheric conditions. Overall, our study highlights the interplay between DES components and reactivity in enhancing CO2 capture efficiency.

Prediction of CO2 absorption in aqueous 1DMA2P solutions using thermodynamics and molecular dynamic simulations

AbstractThis study employs thermodynamic methods and molecular dynamics simulations to predict the CO2 absorption capacity, reaction free energies, and densities in aqueous solutions of 1‐dimethylamino‐2‐propanol (1DMA2P). By combining quantum chemical calculations and classical molecular dynamics with optimized force field parameters, the model accurately predicts solution densities, pH values, and CO2 absorption properties. The results show significant non‐ideal behavior in 1DMA2P solutions during CO2 absorption, demonstrating the reliability of the developed model for predicting reaction equilibria and absorption performance, thus providing theoretical support for carbon capture technologies.

Unraveling natural carbonate variability in Narragansett Bay, RI using multiple high temporal resolution pH time series

The increase in atmospheric carbon dioxide (CO2) over the last 200 years has largely been mitigated by the ocean’s function as a carbon sink. However, this continuous absorption of CO2 by seawater triggers ocean acidification (OA), a process in which water becomes more acidic and more depleted in carbonate ions that are essential for calcifiers. OA is well-studied in open ocean environments; however, understanding the unique manifestation of OA in coastal ecosystems presents myriad challenges due to considerable natural variability resulting from concurrent and sometimes opposing coastal processes—e.g. eutrophication, changing hydrological conditions, heterogeneous biological activity, and complex water mass mixing. Developing a mechanistic understanding of carbonate chemistry variability and its drivers across different time scales is a critical first step in identifying the anthropogenic OA signal against background variability and predicting future OA in coastal systems. This study analyzed high temporal resolution pH data collected during 2022 and 2023 from Narragansett Bay, RI—a mid-sized, urban estuary that since 2005 has undergone a 50% reduction in nitrogen loading—with weekly, discrete bottle samples to verify sensor data. Over a year’s worth of data revealed a distinct diurnal cycle of pH, with pH increasing during the day and decreasing during the night, with an average daily range between 0.05 and 0.1 pH units. Further, we observed a strong seasonal cycles with higher mean pH in winter (8.07 ± 0.15) and lower mean pH in summer (7.72 ± 0.07). By separating the drivers of pH variability into effects from temperature, salinity, water mass mixing, biological activity, and air-sea gas flux, we determined that biological production has the most significant influence on pH from daily to annual timescales and in episodic pH changes. To a lesser extent, the seasonal air-sea CO2 exchange and temperature cycle further modified pH on monthly to seasonal timescales. The dominant influence of biological activity in modulating pH has allowed Narragansett Bay’s nutrient reductions, which have been successful in increasing bottom water DO and pH conditions, to modestly reduce summertime surface pH through reduced primary production. This study offers an in-depth understanding of Narragansett Bay’s natural carbonate variability and highlights the sensitivity of an estuary to water management policy. These findings will benefit future OA prediction and will ultimately assist in making environmental management decisions in coastal estuaries with implications for multiple coastal stakeholders.

Glycine and Boric Acid Promoted Accelerated Weathering of Limestone (AWL) Process for CO2 Absorption

Abstract The accelerated weathering of limestone (AWL) process is an efficient, cost-friendly, and eco-friendly CO2 capture technology. However, the low bicarbonate content measured as alkalinity of its produced effluent can cause up to 50% of its captured CO2 to re-enter the atmosphere within one year. To remedy this limitation, this study investigates the use of promoters (i.e., glycine and boric acid) in increasing the reactivity of the AWL process to elevate the effluent’s alkalinity. This work includes the correlation analysis and optimization analysis for promoted AWL to determine the optimum pH and promoter concentration. The correlation analysis revealed that increasing promoter concentration and pH enhance the effluent’s bicarbonate concentration. Based on the established correlation, the design of experiment (DoE) software with a two-level-two-factor central composite configuration was utilized to optimize the process. It was determined that the optimized glycine-promoted condition of 0.27 M and pH 11.52 achieved a maximum bicarbonate concentration of 53,200 mg/L as CaCO3 with an enhancement factor of 652. As for the boric acid-promoted AWL process, the highest bicarbonate concentration achieved was 42,100 mg/L as CaCO3, with an enhancement factor of 525 at 0.50 M and a pH of 11.84. In addition, the regeneration potential of the promoters via the addition of Ca(OH)2 was investigated. It was found that up to 49.68% of glycine can be regenerated, while an approximately 9% regeneration efficiency of colemanite (raw material of boric acid) was achieved. Overall, the study demonstrates the potential of using promoters to improve CO2 capture efficiency in the AWL process, with both glycine and boric acid showing promising results under optimized conditions.

Tracing the formation and migration history: molecular signatures in the atmosphere of misaligned hot Jupiter WASP-94Ab using JWST NIRSpec/G395H

Abstract The discovery of hot Jupiters that orbit very close to their host stars has long challenged traditional models of planetary formation and migration. Characterising their atmospheric composition — mainly in the form of the carbon-to-oxygen (C/O) ratio and metallicity — can provide insights into their formation locations and evolution pathways. With JWST we can characterise the atmospheres of these types of planets more precisely than previously possible, primarily because it allows us to determine both their atmospheric oxygen and carbon composition. Here, we present a JWST NIRSpec/G395H transmission spectrum from 2.8 – 5.1 µm of WASP-94Ab, an inflated hot Jupiter with a retrograde misaligned orbit around its F-type host star. We find a relatively cloud-free atmosphere, with absorption features of H2O and CO2 at detection significances of ∼4σ and ∼11σ, respectively. In addition, we detect tentative evidence of CO absorption at ∼3σ, as well as hints of sulphur with the detection of H2S at a ∼2.5σ confidence level. Our favoured equilibrium chemistry model determines a C/O ratio of $0.49^{+0.08}_{-0.13}$ for WASP-94Ab’s atmosphere, which is substellar compared to the star’s C/O ratio of 0.68 ± 0.10. The retrieved atmospheric metallicity is similar to the star’s metallicity as both are ∼2 × solar. We find that this sub-stellar C/O ratio and stellar metallicity can be best explained by pebble accretion or planetesimal accretion in combination with large-distance migration of the planet.

Prediction of CO2 Solubility in Ionic Liquids Based on Machine Learning and Analysis of SHAP

The combination forms of anions and cations in Ionic liquids (ILs) which was solvent for the absorption of CO2 were extremely numerous. Consequently, a Machine Learning (ML) model of Transformer was used to measure the solubility of CO2 in each new ILs in this study. The model used 8869 data points and encoding anions and cations based on SMILES. The r, R2, RMSE and MAE were used as error indicators. Additionally, a decoding method was referenced for the first time in the field of ML predictions of CO2 solubility in ILs, which improved the data processing results. As a result, the model achieved better predictive standards. SMILES based SHAP analysis was used on the model to understand the black box operation. The results of the SHAP analysis identified the structural factors that influenced the model's results in the solubility of CO2 in ILs.

Thermal Performance, Energy and Environmental Assessment of Bamboobased Panels from Industrial Wastes for Low Carbon Buildings

Insulation is one of the most effective methods for reducing energy consumption in both the heating and cooling of buildings. Selecting the right materials is crucial as, in addition to reducing emissions from the operation phase thanks to high energy efficiency, it is important that innovative materials also have a low impact during the production process. A growing interest focuses on the replacement of synthetic insulations with recycled materials. Among these are by-products from industrial transformation and manufacturing, residues from agro-industrial processes, and farming wastes. Natural materials have substantially less embodied energy than processed materials, so their use in new buildings and refurbishments can make a worthwhile contribution to sustainability. In this scenario, bamboo is an abundant and promising source. Its ability to capture CO2 from the atmosphere, enhanced by its rapid growth, makes it an ally in mitigating climate change and GHG emissions. To sustain its CO2 absorption capacity, bamboo requires regular harvesting. A valuable application of bamboo prunings is in the production of furniture and textiles. Furthermore, due to its exceptional strength-to-weight ratio and resistance to moisture and insects, bamboo is well-suited for manufacturing durable structural components and building materials, particularly in humid climates. This, however, results in a considerable amount of waste generated at various stages of the bamboo life cycle. This work aims to reduce construction environmental impacts using vegetal waste collected from the different phases of bamboo processing to produce monosheet thermoinsulating panels. Bamboo was characterized, milled to the particle size of 1.397 mm and incorporated into the adhesive. As low-impact alternatives to synthetic glues, two vegetal glues were used, specifically cellulose-based, selected based on polymer hydrophobicity and water solubility when dry, influencing the samples’ permeability. Preparation and drying procedure was developed and preliminary tests identified the optimal mixtures which balance mechanical strength and minimum adhesive. 9 circular samples (φ=100 mm) 40 mm thick were prepared mixing bamboo grains with 3 types of glue (vinyl glue, methyl cellulose, 4 % CMC), each used in 3 different concentration levels (50 %, 75 %, 85 %). Thermal conductivity of the panels was experimentally evaluated by C-Therm TCi thermal analyser according to ASTM D7984. Energy saving potential of the best solution was compared to that of commercial synthetic panels through dynamic simulations on a case study building in central Italy. The environmental impact of the new component was assessed through a ‘Cradle to Gate’ LCA. The optimal vegetal glue combination is the 85 %-one. It was observed that for higher densities, the thermal properties worsen. Considering the production phase, the innovative panel’s embodied energy is over 20 % lower than that of traditional insulation material.

Inverted Microdroplets (Microbubbles) Induced Interfacial Water Protonation to Promote Alkaline Release of Amine and Reduce Energy in CCS.

This study engineered a superacidic interface with a pronounced polar electric field within the amine-water system by inducing hydrogen bond charge transfer in interfacial water via inverted microdroplets (microbubbles), thereby stabilizing protons within the interfacial water layer. This mechanism enabled the continuous alkaline release of hindered amines (AMP-MIS), enhancing CO2 absorption load capacity and reducing regeneration energy consumption. Nuclear magnetic resonance and potentiometric titration elucidated the product distribution, while Raman spectroscopy, pH analysis, and conductivity measurements confirmed proton stabilization. Theoretical calculations provided insights into the reaction mechanism. Pilot-scale testing revealed the AMP-MIS system achieved a 74.2% increase in CO2 cyclic load capacity, surpassing the conventional 30 wt % MEA system, with regeneration energy reduced from 3.667 GJ/t CO2 to 1.885 GJ/t CO2. This innovative strategy offers valuable guidance for advancing amine-based decarbonization technologies and reducing carbon emissions in the power industry, representing a pivotal step toward carbon neutrality.

Revisiting the Group-dominant Elliptical NGC 5044 in the Radio Band: Continuum Emission and Detection of H i Absorption

Abstract We present new MeerKAT L-band (continuum and H i) and upgraded Giant Metrewave Radio Telescope (300–850 MHz) observations of the archetypal cool-core group-dominant early-type galaxy NGC 5044. Our new continuum images reveal diffuse, steep spectrum ( α 0.99 GHz 1.56 GHz = − 1.53 ± 0.6 ) radio emission extending about 25 kpc around the unresolved radio core. The observed radio emission overlaps the known X-ray cavities but is not confined to them. We also find the first direct evidence of neutral atomic gas in NGC 5044, in the form of a 3.8σ significant two-component H i absorption line seen against the emission of the active nucleus. The peak velocities are well correlated with the previously reported CO(2–1) absorption, but the H i lines are moderately broader, spanning velocities from 265 to 305 km s−1. We do not detect H i emission but place an upper limit of M H i &lt; 5.4 × 107 M ⊙in the central 15″ (2.2 kpc) of the galaxy. This is significantly less than the estimated molecular gas content and implies a molecular-to-atomic mass ratio of &gt;∼1.7:1, consistent with these gas phases forming through cooling from the hot intra-group medium. We also constrain the spin temperature to T spin ≤ 950 K, indicating that the detected H i is in the cold neutral phase.