Hydration Of Carbon Dioxide Research Articles

Kinetic Formation Process of Carbon Dioxide Hydrate in Porous Sands under 274.15–280.15 K Reaction Temperature and 20–70% Initial Water Saturation

Kinetic Formation Process of Carbon Dioxide Hydrate in Porous Sands under 274.15–280.15 K Reaction Temperature and 20–70% Initial Water Saturation

Cryotherapy with carbon dioxide hydrate enhances immediate recovery of muscle function from neuromuscular fatigue

Cryotherapy with carbon dioxide hydrate enhances immediate recovery of muscle function from neuromuscular fatigue

Unveiling tomorrow: Carbonic anhydrase activators and inhibitors pioneering new frontiers in Alzheimer's disease.

Alzheimer's disease (AD) is a neurodegenerative disorder and a principal basis of dementia in the elderly population globally. Recently, human carbonic anhydrases (hCAs, EC 4.2.1.1) were demonstrated as possible new targets for treating AD. hCAs are vital for maintaining pH balance and performing other physiological processes as they catalyze the reversible hydration of carbon dioxide to bicarbonate and a proton. Current research indicates that hCA plays a role in brain functions critical for transmitting neural signals. Activation of carbonic anhydrase (CA) has emerged as a promising avenue in addressing memory loss and cognitive issues. Conversely, the exploration of CA inhibition represents a novel frontier in this field. By enhancing glial fitness and cerebrovascular health and blocking amyloid-β (Aβ)-induced mitochondrial dysfunction pathways, cytochrome C (CytC) release, caspase 9 activation, and H2O2 generation in neurons, CA inhibitors improve cognition and lessen the pathology caused by Aβ. Recent research has pushed hCAs into the spotlight as critical players in AD pathogenesis and precise therapeutic targets. The captivating dilemma of choosing between hCA inhibitors and activators looms large, as inhibitors reduce Aβ aggregation and improve cerebral blood flow, while activators enhance cerebrovascular functions and restore pH balance. The current review sheds light on the clinical evidence for hCAs and the roles of inhibitors and activators in AD. Additionally, this review offers a fascinating outlook on the data that may aid medicinal chemists in designing and developing new leads that are more effective and selective for upcoming in vitro and in vivo studies, allowing for the discovery and introduction of novel drug candidates for the treatment of AD to the market and into the clinical pipeline.

Carbon dioxide hydrate formation in porous media under dynamic conditions

AbstractInjecting carbon dioxide (CO2) into subsea water zones where the in situ temperatures are below the hydrate‐forming temperature of CO2 has been recently proposed to lock CO2 inside the water zones in solid hydrate form. It is a common concern that CO2 may form hydrates during the injection period that will reduce well injectivity. CO2 injection into sandstone cores under simulated subsea temperatures of 2°C and 3°C was investigated in this study. Experimental result shows that, at 2°C temperature, flowing CO2 at Darcy velocity 0.033 cm/s begins to form hydrate in the sandstone core at about 3.06 MPa (450 psi), which is much higher than the minimum required pressure of 1.5 MPa (220 psi) for CO2 to form hydrate in static condition. The pressure ratio is 450/220 = 2.05. At 3°C temperature, flowing CO2 at Darcy velocity 0.045 cm/s begins to form hydrate in sandstone core at about 3.67 MPa (540 psi), which is much higher than the minimum required pressure of 1.87 MPa (275 psi) for CO2 to form hydrate in static conditions. The pressure ratio is 540/275 = 1.96. The reason why the required minimum pressure for CO2 to form hydrates in dynamic conditions is about double the required hydrate‐forming pressure in static conditions is not fully understood. It is speculated that the shear rate effect of flowing fluids should slow down the growth of hydrate crystals or break down hydrate films, resulting in delayed formation of bulk CO2 hydrates. More investigations in this area are needed in the future.

A Combined Experimental and Computational Study on the Effect of the Reactor Configuration and Operational Procedures on the Formation, Growth and Dissociation of Carbon Dioxide Hydrate

Clathrate hydrate-based technologies are considered promising and sustainable alternatives for the effective management of the climate change risks related to emissions of carbon dioxide produced by human activities. This work presents a combined experimental and computational investigation of the effects of the operational procedures and characteristics of the experimental configuration, on the phase diagrams of CO2-H2O systems and CO2 hydrates’ formation, growth and dissociation conditions. The operational modes involved (i) the incremental (step-wise) temperature cycling and (ii) the continuous temperature cycling processes, in the framework of an isochoric pressure search method. Also, two different high-pressure PVT configurations were used, of which one encompassed a stirred tank reactor and the other incorporated an autoclave of constant volume with magnetic agitation. The experimental results implied a dependence of the subcooling degree, (P, T) conditions for hydrate formation and dissociation, and thermal stability of the hydrate phase on the applied temperature cycling mode and the technical features of the utilized PVT configuration. The experimental findings were complemented by a thermodynamic simulation model and other calculation approaches, with the aim to resolve the phase diagrams including the CO2 dissolution over the entire range of the applied (P, T) conditions.

Study of Carbon Dioxide Hydrates in “Dry Water” Disperse System

Study of Carbon Dioxide Hydrates in “Dry Water” Disperse System

Magnesium-Induced Rapid Nucleation of Tetrahydrofuran Hydrates.

Hydrates are ice-like crystalline structures of hydrogen-bonded water molecules that trap a guest molecule. Hydrates have several applications, including carbon sequestration, gas separation, desalination, etc. A classical major challenge associated with artificial hydrate formation is the very long induction time to nucleate hydrates. This has spurred the development of multiple chemical, mechanical, and electrical strategies to promote nucleation. Presently, we discover that magnesium can significantly promote the nucleation of tetrahydrofuran (THF) hydrates. While magnesium has been recently shown (by our group) to promote the formation of carbon dioxide hydrates (gas-liquid system), this study discovers that the benefits of magnesium extend to liquid-liquid hydrate systems as well. Experiments show that magnesium reduces the induction time for THF hydrate nucleation with deionized (DI) water and saltwater by six and eight times, respectively. Magnesium-induced nucleation rate enhancements for hydrate formation with DI water and saltwater were 12 and 99 times, respectively. Importantly, we demonstrate near-instantaneous nucleation when magnesium is introduced after the hydrate-forming system reaches suitable thermodynamic conditions. We conduct statistically significant measurements of nucleation and XPS analysis to identify the underlying mechanisms responsible for nucleation. We discuss multiple phenomena at play, including chemical and mechanistic promotion pathways. The formation of hydrogen bubbles and the presence of magnesium ions in solution are seen as important to magnesium-based nucleation promotion. Importantly, very low amounts of Mg are consumed in this process unlike in traditional chemical promotion techniques. Overall, our discovery can enable on-demand nucleation of liquid-liquid hydrate systems, which is critical to the development of several applications.

Self-healing of cracks in cement-based materials through bio-mineralization of low air-dependency microorganisms

Microbial self-healing technology for concrete is attracting widespread attention due to its environmentally friendly, non-toxic, and sustainable attributes. Currently, microbial agents utilized in concrete exhibit a high dependence on atmospheric conditions, relying on atmospheric oxygen to activate or capture carbon dioxide from the air for the generation of carbonate ions. This paper introduces an innovative low-dependency microbial restorative aimed at augmenting the self-healing capability of concrete by nearly doubling the available carbonate ions and providing 80 % of them internally, especially targeting deep cracks. A pioneering approach was employed by combining microorganisms that rapidly produce carbon dioxide with those that expedite carbon dioxide hydration. Microbial functional components were meticulously pelletized to create core-shell structure restorative particles, featuring an outer protective layer constructed with low-alkali cement. This study investigates the mechanism through simulation and experimentation, including substrate conversion, carbon dioxide transformation, and the generation and accumulation of carbonate ions and calcium ions. Essentially, this research not only presents a path towards reduced atmospheric dependence but also provides valuable insights for comprehending the mechanism behind microbial self-healing concrete.

Investigation of the effect of the flow rate of coolant on the kinetics of carbon dioxide hydrate growth using sigmoidal growth model

Relaxation time plays a crucial role in studying reaction kinetics and other processes. This study addresses the importance of relaxation time and suggests methods to minimize it. In this article, we adjust the relaxation time by extracting heat from the hydrate formation process through variations in the flow rate of the cooling fluid. It has been demonstrated that heat transfer plays a dominant role in this process. The kinetics of carbon dioxide hydrate growth were evaluated by increasing the flow rate of cooling fluid using modified sigmoidal growth curve equations, including Logistics and Gompertz. It was conducted a nonlinear least-squares regression analysis to fit sigmoidal functions to the cumulative formation curves of hydrate generated from gas uptake in the static reactor over time. The percentage of error between Areal and Amodel shows that the Gompertz model with Q = 14.59 Lit/min at T = 276 K and Q = 20.25 Lit/min at T = 277 K is the best model for predicting the maximum consumption capacity of CO2. The results also showed that increasing the cooling fluid’s flow rate reduces relaxation time at any temperature. Moreover, increasing the flow rate of the cooling fluid decreased the average relaxation time by 2 % to 60 % at T = 276 K and by 7 % to 22 % at T = 277 K compared to the lowest investigated flow rate. Additionally, reducing the experimental temperature while keeping the flow rate of the cooling fluid constant led to a reduction in the relaxation time.

Rapid formation of carbon dioxide hydrate governed by the natural nano-clay for effective carbon dioxide capture

Gas hydrate can separate and capture enormous carbon dioxide (CO2) only using water cages. Capturing CO2 in hydrate form is viewed as a green and effective technology to reduce the global CO2 emission. However, the sluggish kinetics and high cost of kinetics promotors of CO2 hydrate formation limited the application of hydrate-based CO2 capture technology. Here, we used the nano-clay prepared by cheap natural clay to promote the formation kinetics of CO2 hydrate. At the low concentration range, the formation period of CO2 hydrate in the two-dimensional nano-clay dispersion was significantly shorter than that of the one-dimensional nano-clay dispersion. The induction time (5 min) obtained in vermiculite nanoflakes dispersion was shorter than most solid promotors of CO2 hydrate formation kinetics in reported works. Besides, we found that the water molecules near the negatively charged two-dimensional nano-clay surface were more likely to form the cage-like structure than those around the one-dimensional nano-clay surface. The similar hydrogen-bonded structure of the cage-like water with CO2 hydrate made them favorable for the CO2 hydrate formation. These results shed light on the design of the effective kinetics promotors of CO2 hydrate and contribute to develop the hydrate-based CO2 capture technologies.

Hydrates production with gaseous CO2/C3H8 and CH4/C3H8 (90/10 vol%) mixtures and definition of the role of propane during CO2/CH4 replacement processes

Within the range of temperatures suitable for CO2/CH4 replacement, propane can form hydrates at widely milder conditions than those required for methane and carbon dioxide hydrates. Recent studies proved that the addition of minor quantities of propane to carbon dioxide strongly enhances replacement process, both in terms of methane recovery and carbon dioxide storage. At the same time, the capture of propane remains limited, even if the thermodynamic conditions are widely suitable for its capture. This study experimentally provided a coherent explanation of such a process. Hydrates were formed and dissociated on a lab-scale reactor with binary mixtures containing 90 vol% of CO2/CH4 and 10 vol% of C3H8; the results were compared with the phase equilibrium conditions of the pure species, obtained with the same procedure. The promoting/inhibiting effect of propane on the forming system was quantified and explained in terms of typology of hydrate structure formed and cage occupancy. Based on the results achieved in this study, the replacement mechanism, in presence of propane, was finally characterized and compared with the results obtained when replacement was carried out with the same procedure but with pure carbon dioxide and CO2/N2 mixtures.

Comparative study of stability and activity of wild-type and mutant human carbonic anhydrase II enzymes using molecular dynamics and docking simulations

The human carbonic anhydrase II (HCA II) enzyme is a cytosolic protein that catalyzes the reversible hydration of carbon dioxide (CO2). Considering the critical role of the HCA II and the effects of some mutations on the activity and stability of the enzyme in humans, several computational methods are used to study the structure and dynamics of the wild-type and the mutant enzymes with three ligands, CO2, 4-nitrophenyl acetate and acetazolamide. Our results of MD simulation of a wild-type enzyme with 4-nitrophenyl acetate show that it created essential effects on the fluctuation of this enzyme and made it more unstable and less compact than the same enzyme without ligand. In the MD of the mutant enzyme with 4-nitrophenyl acetate ligand, no significant difference is observed between with and without ligand. The affinity of the wild-type enzyme to the 4-nitrophenyl acetate is notably higher than the mutant enzyme with the same ligand. Furthermore, results showed that wild-type and mutant enzymes with CO2 are more favorable in stability and flexibility than the same enzymes without ligand. The MD results of wild-type with acetazolamide indicate instability compare without ligand, but in MD of mutant enzyme with acetazolamide show that it more stable and compact than the same enzyme without ligand. Finally, Comparing protein trajectories to assess the impact of ligands on the stability and activity of HCA II enzymes can have medical applications and can in the engineering and design of new variants of carbonic anhydrase enzyme.

Molecular insights into the synergistic inhibition mechanisms of antifreeze protein and methanol on carbon dioxide hydrate growth

The formation of CO2 hydrates during CO2 transportation and deep-sea injection poses a significant risk of pipeline blockage. Combining kinetic (KHIs) and thermodynamic hydrate inhibitors (THIs) serves as a promising efficient and economical strategy to mitigate this issue, whose performance and microscopic mechanisms yet are still poorly understood. This study employs molecular dynamics simulations to explore the effects of the combination of winter flounder antifreeze protein (wf-AFP) as a KHI and methanol as a THI on CO2 hydrate growth. We find that methanol and wf-AFP exhibit an intriguing synergistic inhibition performance on hydrate growth. In the AFP-only system, AFP serves as a spatial hindrance near the hydrate growth interface. However, in the AFP + methanol system, AFP changes its position due to the attractive force of methanol. Part of the AFP fragment remains on the hydrate interface, while the rest surrounds the CO2 droplet. Methanol, in addition to disrupting the water structure, combines with AFP to act as a double barrier to CO2 dissolution into the aqueous solution, thereby significantly reducing the gas source for hydrate growth. These findings provide molecular-level insights into hydrate inhibition mechanisms and guide the design of efficient inhibitors for safe CO2 transportation and injection.

Molecular insights into the performance of promoters for carbon dioxide hydrate

Hydrate-based CO2 storage is a cost-effective and environmentally friendly approach to reduce carbon emission, and the addition of hydrate promoters has shown a promising avenue for enhancing CO2 hydrate formation. In this work, the promotion mechanism and promotion performance of five different hydrate promoters (denoted as DIOX, CP, THF, THP, and CH) were investigated and compared by first-principles calculations and molecular dynamics simulations. The results show that the hydrate promoters prefer to singly occupy 51264 cages of the sII hydrate, and CO2 molecules can singly occupy 512 cage or multiply occupy 51264 cages. The cohesive energy density indicates that the optimum CO2 storage capacity can reach up to ∼28 wt%. The stabilization effects of hydrate promoters on the hydrate stability should follow the order of CP > CH > DIOX > THF ≈ THP. The hydrate promoters can increase the water-water interactions, and the molecular diffusivity shows that the dynamic stability of the hydrates is THP ≈ CH > CP > DIOX > THF. Further, the hydrate promoters can accelerate the hydrate formation kinetics, which reduce the induction time and increase the nucleation and growth process.

Experimental and thermodynamic modelling of hydrate dissociation conditions for CO[formula omitted] + propane mixtures

The possibility of hydrate formation poses a central issue for Carbon Capture and Storage (CCS) and Enhanced Oil Recovery with Water-Alternating-Gas (EOR/WAG) injection projects. In most of the cases, however, the available fluid for this purpose consists of a CO2-rich stream containing contaminants such as hydrocarbons and permanent gases. As a result, there is a growing interest in evaluating the effect of small impurities concentrations on the phase behaviour of such streams. This work investigates the impact of propane as a promoter in carbon dioxide hydrate formation, covering a concentration range in the feed gas phase between 10 and 69% on mole basis. The study also considers the Lw-LCO2-H region, taking into account liquid and supercritical transportation commonly encountered in CCS projects. Additionally, a procedure to estimate uncertainties in the graphical determination of the dissociation temperature and pressure is discussed. The thermodynamic modelling approach includes three different modifications of cubic equations of state (CEoS): asymmetric mixing rule, advanced Huron-Vidal mixing rule, and cubic-plus-association approach. An alternative procedure based on setting different sets of CO2 Kihara’s parameters when shifting between structures was also used. While satisfactory average temperature deviations were obtained for those equations of state, maximum deviation between calculated and experimental temperatures spanned from 0.5 to 2.5 K, depending on the thermodynamic model.

Effect of sucrose fatty acid ester on crystal growth of carbon dioxide hydrate in aqueous fructose solution

CO2 hydrate is a remarkable candidate for novel solid carbonated foods because of its large gas capacity. This paper reports the effect of surfactants, essential additives in food production, on hydrate crystal growth by visually observing the CO2 hydrate crystal growth in aqueous fructose + sucrose fatty acid ester solution + gaseous CO2 system. Under all thermodynamic conditions, the surfactants affected the crystal growth of CO2 hydrates at liquid/gas interface, while not influencing growth in the liquid bulk phase. Porous hydrate crystals were formed at the liquid/CO2 interface and grew continuously along the reactor wall. The hydrate crystal morphology in liquid bulk phase was not affected by surfactants, changing from polyhedral and polygonal to dendritic shapes as temperature decreased. Discussion is provided on how the observation results can be specifically applied to intensification of hydrate formation process design and evaluation of hydrated food texture.

Carbon Dioxide Hydrate Kinetics in Porous Media with Montmorillonite Suspensions: A Study on Behavior and Interactions

Carbon Dioxide Hydrate Kinetics in Porous Media with Montmorillonite Suspensions: A Study on Behavior and Interactions

Production Phases of Methane and Carbon Dioxide Hydrates Intended for Energy Conversion

Production Phases of Methane and Carbon Dioxide Hydrates Intended for Energy Conversion

Effect of Surfactants on the Synthesis and Dissociation of Gas Hydrates

The synthesis and dissociation of methane hydrate and carbon dioxide hydrate were studied. Nonflammable gas hydrates can be used to extinguish flames in confined spaces. To increase the extinguishing efficiency, it is necessary to increase the dissociation rate (gas release rate) by using surfactant. The work investigates gas hydrates synthesized using sodium dodecyl sulfate (SDS). Experimental studies were carried out in wide ranges of surfactant concentration, the number of the stirrer revolutions and the initial water volume. To achieve the maximum rate of synthesis and dissociation, optimization of the specified parameters was performed. The influence of the key parameters on the dissociation rate was investigated experimentally and theoretically. The novelty of the work lies in solving a complex of interrelated tasks on the synthesis and dissociation of gas hydrate. It is shown that in order to achieve the maximum dissociation rate of carbon dioxide hydrate, it is necessary to optimize the following parameters: the diameter of the particles and their porosity, the porosity of the layer and the external heat flux.

Ultrafast Formation of Carbon Dioxide Hydrate Foam for Carbon Sequestration

Ultrafast Formation of Carbon Dioxide Hydrate Foam for Carbon Sequestration