Diffusion Of Carbon Dioxide Research Articles

Hydrogen and Carbon Dioxide Kinetic Adsorption and Diffusion Behavior into Organic-Rich Shale: Implications of Mineralogy and Organic Content

Hydrogen and Carbon Dioxide Kinetic Adsorption and Diffusion Behavior into Organic-Rich Shale: Implications of Mineralogy and Organic Content

Effect of background wind and dissipation processes on the diurnal component of atmospheric solar tides

The radiation coming from the Sun heats the Earth’s atmosphere and generates atmospheric tides. In this paper, we model atmospheric tides in the presence of background wind and dissipation processes and investigate their effects. The equations for tidal oscillations of wind and temperature in the atmosphere encompass factors such as background wind, temperature profile, and background composition including ozone, carbon dioxide, hydro-magnetic interactions, Newtonian cooling, eddy, and molecular diffusion. These components interact to define the behavior of tidal phenomena comprehensively. Thermal forcing processes include the insolation absorption of H2O in the troposphere, O3 in the stratosphere, and a contribution from O2 absorption in the thermosphere. The method of solution for the equations is outlined for the solar diurnal tides during the March equinox by considering all these dissipation processes and the background wind. The obtained results are in good agreement with the Global Scale Wave Model (GSWM-00). It is found that the background wind plays significant role in affecting the horizontal wind oscillations below 100 km. At higher altitudes (100–200 km), the background wind, ion drag force, divergence of momentum, and heat fluxes due to molecular and eddy diffusion have a considerable role in affecting the zonal and meridional winds.

Simulating carbon dioxide diffusion during airflow merging in Y-shaped bifurcated tunnels after blasting operations

This research aims to evaluate the dilution and discharge effects of noxious gas produced by the drilling and blasting method under the merging of airflows during the ventilation of Y-shaped bifurcated tunnels. A finite volume model was utilized to simulate the overall diffusion process of explosion and noxious gas in the tunnel after blasting, taking into account various parameters of bifurcated structures. The flow field characteristics and the temporal and spatial evolution of the CO concentration field was analyzed under parameters including the bifurcating angle θ and cross-sectional area ratio F, as well as air supply ratio Q. The results show that the CO concentration decreases in a negative exponential manner with the ventilation time and it reaches the concentration limit within 480–610 s. By comparing conditions under different bifurcating angles θ of the main transverse tunnel, the dilution effect of CO is optimal when θ is 90° and the CO concentration reaches the safety threshold after ventilation for 489 s. Considering the influence of the cross-sectional area ratio (F) of the main transverse tunnel, the CO concentration reduces most rapidly when F is 0.7 and it reaches the safety threshold after ventilation for 476 s. Upon estimating the influence of the air supply ratio (Q) on the CO diffusion process, it is found that Q of 0.4 is most conducive to the dilution and discharge of CO and the CO concentration reaches the safety threshold after ventilation for 485 s. The results provide technical and theoretical support for the ventilation and smoke discharge during the construction of a Y-shaped bifurcated tunnel.

Characterizing competitive adsorption and diffusion of methane and carbon dioxide in kerogen type-III slit model

Characterizing competitive adsorption and diffusion of methane and carbon dioxide in kerogen type-III slit model

MODELLING OF INTERNAL TRANSFORMATIONS OF GAS PHASE IN POROUS MEDIA

The paper presents the research of temperature change in the investigated medium during dynamic expansion of gas (CO2) generated in reservoir conditions, diffusion of carbon dioxide into the displacing fluid and their influence on the displacement process. In-situ gas generation can provide a way to control the nonequilibrium fractal state at the interface under displacement in a porous medium. The change from fractal growth to non-fractal growth can be characterised as a function of density and viscosity ratios. This effect is shown in the increase of hydrocarbon displacement coefficient due to the equalisation of densities of displacing and displaced agents as a consequence of the increase in gas saturation of the fluid.

A Guideline for Greenhouse Gas Emission Reduction and Carbon Sequestration in Forest Sector Based on Thailand Voluntary Emission Reduction Programme

Currently climate change and global warming have significant impact on the environment toward biodiversity and human quality of life. Major cause derives from human activities that produce greenhouse gas emission especially the diffusion of carbon dioxide to the atmosphere. One way to address global warming is to increase the absorption potential of greenhouse gases, especially carbon dioxide. The best natural method is forest adsorption whereby trees absorb carbon dioxide and store it in the form of biomass through photosynthesis. Therefore, forests are a highly efficient source of carbon sinks. The main objective of this research was to implement a methodology for greenhouse gas reduction and carbon sequestration assessments in forest sector according to Thailand's standards known as the Thailand Voluntary Emission Reduction Program (T-VER). According to climate change, reduction of greenhouse gas process will use methodology of T-VER-METH-FOR-01 Version 2 (Sustainable Forestation)andT-VER-TOOL-FOR/AGR-01 Version 2(Calculation for Carbon Sequestration). The Baseline Sequestration/Emissionand Project Sequestration/ Emission as well as plant diversity assessment in project area as greenhouse gas activity will be used for the calculation. The results of this development of prototype project could be used for concluding content of greenhouse gas from 134.72 ha of the research area and it was shown that Baseline Sequestration was 19,618.95 tCO2e. When calculating Project Sequestration for 10 years, carbon content could be increased by 27,617.95tCO2e calculated to be 800.61tCO2e/yr. Therefore, total Project Sequestration was 8,006.13tCO2e.

Carbon sequestration through mineral carbonation: Using commercial FGD-gypsum from a copper smelter for sustainable waste management and environmental impact mitigation

In this study, we conducted a comprehensive examination of a commercial FGD gypsum produced in a Copper (Cu) smelter process and delved into its potential use as a Calcium (Ca)-rich material for ex-situ mineral carbonation by exploring the partitioning and fate of these metal impurities. The resulting carbonation end-product displayed a calcium carbonate (CaCO3) content of 71.1%, featuring a relatively low CO2 conversion, which may be attributed to the presence of metallic impurities in the commercial FGD-gypsum. Most of these metallic impurities, acting as inputs to the carbonation process, originate from the parent FGD-gypsum matrix. This results in an increased ionic strength within the FGD gypsum, potentially impeding the diffusion of carbon dioxide (CO2) from the gas phase to the aqueous phase. The partitioning and examination of the speciation of major, minor, and trace elements at all stages of CO2 conversion allowed us to propose four potential reaction pathways influencing carbonation efficiency: (i) the formation of metal carbonates, (ii) the production of metal oxides and oxyhydroxides, (iii) the development of metal multiform compounds, and (iv) elements deviating from the outlined patterns. Commercial FGD-gypsum is suitable for acceptance at non-hazardous waste landfills. However, it's essential to highlight that leaching values of As exceed the inert range and non-hazardous waste standards in commercial FGD-gypsum. Although most heavy metal leaching values from the carbonate end-product stay below non-hazardous limits, the release of some heavy metal leachates from the carbonate end-product may limit reuse options for these materials.

Effect of vinyl acetate/dibutyl maleate copolymers on gas transport properties of poly(ethylene oxide-b-amide 6) membranes: a comprehensive study on permeability, diffusivity, solubility, and permselectivity of carbon dioxide

Effect of vinyl acetate/dibutyl maleate copolymers on gas transport properties of poly(ethylene oxide-b-amide 6) membranes: a comprehensive study on permeability, diffusivity, solubility, and permselectivity of carbon dioxide

Gas in scattering media absorption spectroscopy for time-resolved characterization of gas diffusion processes in porous materials

Signal denoising is a serious problem for in-situ laser diagnostics of gases dispersed in porous materials. An optical sensor system based on absorption spectroscopy of gases in a scattering environment was built using a 3D printed cell with reference samples of polystyrene foam. Selected A-band spectral lines of molecular oxygen were investigated using wavelength modulated spectroscopy with second harmonic detection. Quantitative information on the concentration of analyte dispersed in the porous medium was obtained at extremely low signal-to-noise ratio (SNR < 10). A spectral line shape fitting procedure based on the Gabor transform followed by a filtered inverse fast Fourier transform allowed to achieve a relatively high SNR with good linearity over a range of reduced oxygen concentrations in air. Finally, the applicability of the optical sensor system to monitor the diffusion of carbon dioxide into air dispersed in a Styrofoam sample and vice versa was successfully demonstrated.

Causes and consequences of gas bubble trauma on fish gill function.

Total dissolved gas supersaturation (TDGS) occurs when air mixes with water under pressure, which can be caused by features such as hydroelectric dams and waterfalls. Total dissolved gas supersaturation can cause harmful bubbles to grow in the tissues of aquatic animals, a condition known as gas bubble trauma (GBT). As gills are the primary gas exchange surface for most fish, it is through the gills that elevated total dissolved gases enter the blood and tissues of a fish. We describe the role of the gills in admitting TDGS into the body and discuss potential effects of bubbles in the gills on blood oxygen and carbon dioxide diffusion, blood ion and pH homeostasis, and nitrogenous waste excretion, as well as downstream effects on aerobic swimming performance.

Symptomatic post COVID patients have impaired alveolar capillary membrane function and high VE/VCO2

BackgroundPost COVID-19 syndrome is characterized by several cardiorespiratory symptoms but the origin of patients’ reported symptomatology is still unclear.MethodsConsecutive post COVID-19 patients were included. Patients underwent full clinical evaluation, symptoms dedicated questionnaires, blood tests, echocardiography, thoracic computer tomography (CT), spirometry including alveolar capillary membrane diffusion (DM) and capillary volume (Vcap) assessment by combined carbon dioxide and nitric oxide lung diffusion (DLCO/DLNO) and cardiopulmonary exercise test. We measured surfactant derive protein B (immature form) as blood marker of alveolar cell function.ResultsWe evaluated 204 consecutive post COVID-19 patients (56.5 ± 14.5 years, 89 females) 171 ± 85 days after the end of acute COVID-19 infection. We measured: forced expiratory volume (FEV1) 99 ± 17%pred, FVC 99 ± 17%pred, DLCO 82 ± 19%, DM 47.6 ± 14.8 mL/min/mmHg, Vcap 59 ± 17 mL, residual parenchymal damage at CT 7.2 ± 3.2% of lung tissue, peakVO2 84 ± 18%pred, VE/VCO2 slope 112 [102–123]%pred. Major reported symptoms were: dyspnea 45% of cases, tiredness 60% and fatigability 77%. Low FEV1, Vcap and high VE/VCO2 slope were associated with persistence of dyspnea. Tiredness was associated with high VE/VCO2 slope and low PeakVO2 and FEV1 while fatigability with high VE/VCO2 slope. SPB was fivefold higher in post COVID-19 than in normal subjects, but not associated to any of the referred symptoms. SPB was negatively associated to Vcap.ConclusionsIn patients with post COVID-19, cardiorespiratory symptoms are linked to VE/VCO2 slope. In these patients the alveolar cells are dysregulated as shown by the very high SPB. The Vcap is low likely due to post COVID-19 pulmonary endothelial/vasculature damage but DLCO is only minimally impaired being DM preserved.

Molecular Dynamics Simulation Study of the Diffusion of Carbon Dioxide in Heptane: Application in Natural Gas Cleaning

Using solvents to remove carbon dioxide is an effective way to purify natural gas. Diffusion of solute in solvent is key to natural gas purification. In this study, molecular dynamics (MD) simulations of the diffusion of carbon dioxide in heptane at different temperatures and pressures were performed to simulate the conditions of industrial purification process. The diffusion coefficients were measured in two different configurations; pure solvent and binary solute-solvent systems. The diffusion coefficients of the binary system were observed to be in the order of 10-9 m2/s. An increased temperature was observed to increase the diffusion coefficient of the carbon dioxide in heptane while an increase in pressure reduced the value of the diffusion coefficient. The diffusion coefficient was also observed to follow an Arrhenius-type relationship with respect to temperature. The activation energy of the system increased from 9.228 kJ/mol to 11.139 kJ/mol with pressure increase. A linear relationship was detected between the diffusion coefficient and the viscosity of the system and an increased viscosity of the system results in a decreased diffusion coefficient. The results of the research showed that carbon dioxide behavior in heptane offers the theoretical backing for the development of a new natural gas desulphurization solvent.

The Influence of Seasonal Variability of Eutrophication Indicators on Carbon Dioxide and Methane Diffusive Emissions in the Largest Shallow Urban Lake in China

Eutrophication is prevalent in urban lakes; however, a knowledge gap exists regarding eutrophication influences on carbon dynamics in these ecosystems. In the present study, we investigated the carbon dioxide (CO2) and methane (CH4) concentration and diffusion fluxes in Lake Tangxun (the largest shallow Chinese urban lake) in the autumn and winter of 2022 and spring and summer of 2023. We found that Lake Tangxun served as a source of GHGs, with average emission rates of 5.52 ± 12.16 mmol CO2 m−2 d−1 and 0.83 ± 2.81 mmol CH4 m−2 d−1, respectively. The partial pressure of dissolved CO2 (pCO2) (averaging 1321.39 ± 1614.63 μatm) and dissolved CH4 (dCH4) (averaging 4.29 ± 13.71 μmol L−1) exceeded saturation levels. Seasonal variability was observed in the pCO2 and dCH4 as well as CH4 fluxes, while the CO2 flux remained constant. The mean pCO2 and dCH4, as well as carbon emissions, were generally higher in summer and spring. pCO2 and dCH4 levels were significantly related to total nitrogen (TN), total phosphorus (TP), and ammonium-nitrogen (N-NH4+), and N-NH4+ was a main influencing factor of pCO2 and dCH4 in urban eutrophic lakes. The positive relationships of pCO2, dCH4 and trophic state index highlighted that eutrophication could elevate CO2 and CH4 emissions from the lake. This study highlights the fact that eutrophication can significantly increase carbon emissions in shallow urban lakes and that urban lakes are substantial contributors to the global carbon budget.

A detailed molecular dynamics simulation and experimental investigation of CO2 adsorption on graphene oxide-polyaniline nanocomposite

The study investigated the sorption and diffusion of carbon dioxide on Graphene oxide-polyaniline (GO-PANI) using volumetric method and molecular dynamics simulations. The experimental results showed that GO-PANI was more effective at adsorbing CO2 than either of the individual materials alone. Simulations supported this trend in CO2 adsorption and provided additional insights into the structural information of the adsorbents and the dynamics of CO2 molecules. The Langmuir adsorption model was employed to fit sorption isotherms computed using Grand Canonical Monte Carlo (GCMC) method. The GO-PANI nanocomposite compound exhibited a superior adsorption rate compared to pure structures. The isosteric heat for CO2 adsorption was 27.59 kJ/mol. The interaction energy of single molecules of CO2 on GO-PANI surface was −38.075 kcal/mol. Diffusion coefficient value for CO2 was 41.2 × 10 −9 m2/s, lower than that of the pure polymer. FT-IR, FE-SEM, and BET techniques were used to analyze synthesized GO-PANI structure. The highest CO2 adsorption was observed at a temperature of 283 K. Isosteric heat adsorption decreased with uniform surface charge. This research provides critical microscopic information on gas adsorption in polymer nanocomposites and demonstrates the effectiveness of GO-PANI as an efficient adsorbent for carbon dioxide, which could be useful in various industrial applications.

Effect of fly ash on compressive strength, carbonation and corrosion resistance of reinforced concrete: a systematic review

Purpose The purpose of this paper is to study and analyze the effects of fly ash (FA) as a mineral admixture on compressive strength (CS), carbonation resistance and corrosion resistance of reinforced concrete (RC). In addition, the utilization of inexpensive and abundantly available FA as a cement replacement in concrete has several benefits including reduced OPC usage and elimination of the FA disposal problem. Design/methodology/approach Reinforcement corrosion and carbonation significantly affect the strength and durability of the RC structures. Also, the utilization of FA as green corrosion inhibitors, which are nontoxic and environmentally friendly alternatives. This review discusses the effects of FA on the mechanical characteristics of concrete. Also, this review analyzes the impact of FA as a partial replacement of cement in concrete and its effect on the depth of carbonation in concrete elements and the corrosion rate of embedded steel as well as the chemical composition and microstructure (X-ray diffraction analysis and scanning electron microscopy) of FA concrete were also reviewed. Findings This review provides a clear analysis of the available study, providing a thorough overview of the current state of knowledge on this topic. Regarding concrete CS, the findings indicate that the incorporation of FA often leads to a loss in early-age strength. However, as the curing period increased, the strength of fly ash concrete (FAC) increased with or even surpassed that of conventional concrete. Analysis of the accelerated carbonation test revealed that incorporating FA into the concrete mix led to a shallower carbonation depth and slower diffusion of carbon dioxide (CO2) into the concrete. Furthermore, the half-cell potential test shows that the inclusion of FA increases the durability of RC by slowing the rate of steel-reinforcement corrosion. Originality/value This systematic review analyzes a wide range of existing studies on the topic, providing a comprehensive overview of the research conducted so far. This review intends to critically assess the enhancements in mechanical and durability attributes (such as CS, carbonation and corrosion resistance) of FAC and FA-RC. This systematic review has practical implications for the construction and engineering industries. This can support engineers and designers in making informed decisions regarding the use of FA in concrete mixtures, considering both its benefits and potential drawbacks.

Development and verification of an integrated hydration, geochemical and transport model for the hydrated cement paste exposed to an aggressive chemical environment

This study established a new transport model by using the COMSOL-IPHREEQC interface to simulate the changes in the morphology of hydrated cement paste due to the diffusion of carbon dioxide and chloride ion. A series of constitutive models such as the cement hydration model (to compute the dissolution rate of each clinker mineral), thermodynamic model (to perform the hydration reaction, reaction due to transport of ions, chemical and physical adsorption of chloride ion during the chloride ion ingression and dissolution rate of calcium-silica-hydrate (C–S–H) simultaneously with portlandite for the carbonation), porosity determination, and COMSOL Multiphysics (for the calculation of transport problems) were integrated using MATLAB language to determine the pore solution chemistry, hydrates assemblage, and porosity of the cement paste exposed to aggressive environments. During the diffusion of carbon dioxide gas, the decalcification of C–S–H was realistically considered by assuming that the Ca/Si ratio of C–S–H decreased from 1.67 (Jennite type C–S–H) to 0.67 (Tobermorite C–S–H), and then from 0.67 to 0 (silica gel). The proposed integrated platform was well verified with different sets of reported and raw experimental results and existing models, indicating a realistic predictability for chloride ion ingression and carbonation. The developed model discloses the effect of coupling the progression of hydration with reaction due to the transport of ions by using the free chloride ion profile and phase assemblages during the chloride ion ingression.

Carbon nanotubes with CoNi alloy nanoparticles growing on porous carbon substrate as cathode for Li-CO2 batteries

The over-exploitation of fossil fuels and rapid industrialization has released a large number of carbon dioxide. As a major greenhouse gas, it can induce the increasing global temperature and result in environmental issues. It is an urgent necessity to reduce carbon dioxide emission and increase carbon capture, utilization and storage. Li-CO2 battery can be used for the fixation and conversion of carbon dioxide to electrochemical energy. However, it is necessary to explore and design efficient catalysts, due to the low electronic conductivity and sluggish decomposition kinetics for lithium carbonate as the discharge product. Herein, carbon nanotubes with CoNi alloy nanoparticles growing on porous carbon substrate (PC/CoNi-CNTs) is designed by immersing porous melamine formaldehyde sponge into cobalt nitrate and nickel chloride solution with the subsequent carbonization. The porous structure of carbon substrate facilitates the electrolyte infiltration and carbon dioxide diffusion. The carbon nanotubes and CoNi alloy catalysts can efficiently enhance the reversible deposition and decomposition of lithium carbonate and carbon, taking advantage of their synergistic effect. At a current density of 0.05 mA cm−2, the terminal discharge and charge voltages are 2.76 and 4.23 V with a limited specific capacity of 0.2 mA h cm−2, respectively. These results demonstrat that the design of carbon nanotubes with alloy nanoparticles on porous carbon substrate as cathode can enhance the electrochemical performances of Li-CO2 battery.

Combined sand eco-mortar reinforced with polyethylene Terephthalate: Behavior and optimization using RSM method

Today, economic and environmental interests have become imperative in construction works. Therefore, the use of substitute materials for natural aggregates or cement contributes to the preservation of natural resources and the reduction of carbon dioxide diffusion. The large quantity of dune sand available in the Algerian Sahara and the affordable cost of recycled aggregates and plastic waste encourage their use as a replacement for natural aggregates in the production of cementitious materials. The interaction of dune sand (DS) and recycled sand (RS) with the introduction of a polyethylene terephthalate (PET-F) fibre help to design a normative ecological material. The aim of the study was to explore and optimize the proportions of these materials to create an environmentally-friendly cementitious product. The strategy is based on the progressive substitution of dune sand by another originating from demolition waste at different rates: 0%, 25%, 50%, 75% and 100%, and a gradual rate of PET-F fibres, 20 and 30 mm from 0% to 2% with a step of 0.5%. In this article, we study the effect of the new composites on the physico-mechanical performance of the designed eco-mortars through several tests (spreadability, fresh density, porosity, capillary and immersion absorption, compression strength, and flexural strength). In addition, we utilise Response Surface Methodology (RSM) to predict approximate parameters that influence the properties of new cementitious composites. The results obtained show the significant benefit of the following rates: 50% SD, 50% SR and (0.5%, 30 mm) PET-F fibre. Thus, the RSM model correlates well with the experimental data, which has undoubtedly led to an improvement in the physical–mechanical characteristics of the eco-mortar studied. Otherwise, the proposed model reaches a high pertinence, with a good desirability coefficient of 0.917.

On Mathematical Models of Degradation Processes According to ISO 16204 and fib Model Code

AbstractThe main factors affecting the service life of concrete structures are the presence of chloride ions and carbon dioxide, alternating frost action and mechanical stresses on the structure. In practice, these effects can be taken into account by using mathematical modelling of these phenomena. In this contribution, the authors focus on the processes of chloride ions and carbon dioxide (carbonation process) diffusion through concrete and the associated subsequent corrosion of reinforcement. Mathematical models recommended by the fib Model Code and ISO 16204 are described and the effect of simultaneous environmental and mechanical load on the service life of the structure is discussed. The models are used to study the residual service life of a simple reinforced concrete frame bridge based on the percentage loss of reinforcement area analysis over time.

Modeling the durability of novel cementitious materials prepared with CEM II/C-M exposed to drying and carbonation

The behavior upon exposure to CO2 of novel cementitious materials prepared with a low clinker cement CEM II/C-M (S-LL) is investigated in this paper. A simplified carbonation model considering the dissolution of a combined Ca-containing hydrate phase (CH, C-S-H, ettringite, monocarbonate, and Si-hydrogarnet) and the precipitation of calcite according to the evolution of phase assemblages calculated with thermodynamic modeling is applied to simulate accelerated carbonation tests in the laboratory. The dissolution rate of the Ca-containing hydrate phase is assumed to be determined by the water saturation degree, the partial pressure of CO2, and the fraction of its remaining volume compared to the initial one, which provides a way to predict the precipitation rate of calcite. Two mass conservation equations are considered in the model: water migration through the connected pores and diffusion of carbon dioxide in gaseous phases. Selected physical variables representative of the reactive transport properties are quantified from experimental measurements, including dynamic vapor sorption tests and drying experiments. The model response is compared to experimental data in terms of portlandite profiles from thermogravimetric analysis, and carbonation depth measurements using a pH indicator after specific times of accelerated carbonation. These experiments were also performed on a reference mortar prepared with the CEM II/A-S cement. All experimental results were simulated with the simplified carbonation model and the results compared to the response of the novel material.