Carbon Dioxide Solvent Research Articles

Machine learning boosted eutectic solvent design for CO2 capture with experimental validation

AbstractAlthough eutectic solvents (ESs) have garnered significant attention as promising solvents for carbon dioxide (CO2) capture, systematic studies on discovering novel ESs linking machine learning (ML) and experimental validation are scarce. For the reliable prediction of CO2‐in‐ES solubility, ensemble ML modeling based on random forest and extreme gradient boosting with inputs of COSMO‐RS derived molecular descriptors is rigorously performed, for which an extensive experimental CO2‐in‐ES solubility database of 2438 data points in 162 ESs involving 106 ES systems are collected. With the best‐performing model obtained, the CO2 solubilities of 4735 novel combinations of ES components are first predicted for estimating their potential in CO2 capture. The top‐ranked candidate combinations are subsequently evaluated by examining the environmental health and safety properties of individual components and assessing the potential operating window based on solid–liquid equilibrium (SLE) prediction. Three most promising ES systems are finally retained, which are thoroughly studied by SLE and CO2 absorption experiments.

Surface coating method for cement-based materials to improve chloride ion penetration resistance using amine-based CO2 solvent

The application of coatings on concrete surfaces serves as a protective shield, guarding the structure against chlorides and averting corrosion of the reinforcement, consequently enhancing its durability. This study investigates the resistance of cement mortar samples to chloride ion penetration when coated with an amine-based carbon dioxide (CO2) solvent. Various factors, including monoethanolamine (MEA) concentrations of 1, 10, and 30 wt%; water-to-cement ratios (w/cm) of 0.35, 0.4, and 0.5; coating timings on day 3 and day 27; and pre-conditioning methods such as air drying, are investigated for their impact on the performance of chloride penetration resistance. Specifically, pre-conditioning significantly enhanced the performance of the coatings, especially in samples with a higher w/cm. Coatings applied at an early stage demonstrated superior resistance to chloride ion penetration compared to those applied later in the curing process. Moreover, solutions with higher concentrations of MEA, capturing more CO2, encouraged the resistance against chloride penetration by reducing capillary macropores within the cement mortar samples. Diffusivity analysis of the coated surface layer confirmed the efficacy of the CO2-dissolved MEA solution as a barrier against chloride ion penetration. Optimal performance was possibly observed in the samples produced by a w/cm of 0.4 and their treatment with more than 10% MEA concentrations.

DESAIN DAN PEMBUATAN MESIN EKSTRAKSI SUPERKRITIS BERBASIS CO2 CAIR UNTUK MENGEKSTRAKSI SENYAWA BIOAKTIF

Bioactive compounds in animal and plant cells have many benefits for human health, such as antioxidants, antibacterial, anti-inflammatory, and anticancer. Extraction and separation of bioactive compounds from other compounds is an important step, and commonly, conventional methods are used, but these methods have disadvantages, like producing unwanted compounds. Alternative methods can be conducted using supercritical fluid extraction, but this equipment is expensive and has a small capacity. So, this study aims to produce functional and structural designs and manufacture supercritical fluid extraction machines using carbon dioxide solvents (CO2) operating with a semi-continuous system. This research succeeded in designing and manufacturing a supercritical fluid extraction machine using carbon dioxide (CO2) solvent that operates in a semi-continuous system for the extraction of bioactive compounds, with main components including cover frames, supercritical extractor chamber, low and high-pressure CO2 tubes, compressors and boosters, pipelines, direct valves, manometers, heating, cooler, and expanders, result from reservoirs and automatic control. Moreover, the preliminary simulation test studies revealed that the supercritical extractor chamber could withstand an absolute pressure of 1000 bar, a temperature of 300°C, and a work capacity of 1 L. It indicated that the supercritical CO2 fluid extractor system was performing well for the conditioning of the extractor chamber, which is generated using a booster and controlled by a one-way valve. Then, the extract is transferred to the separation chamber to separate the CO2 gas. Then, CO2 gas is returned to the low-pressure CO2 tubes for recycling and reuse for the following process.

Novel reaction systems for catalytic synthesis of structured phospholipids.

Phospholipids are distinctive, adaptable molecules that are crucial to numerous biological systems. Additionally, their various architectures and amphiphilic characteristics support their unrivaled crucial functions in scientific and industrial applications. Due to their enormous potential for use in the fields of medicine, food, cosmetics, and health, structured phospholipids, which are modified phospholipids, have garnered increased attention. Traditional extraction methods, however, are pricy, resource-intensive, and low-yielding. The process of enzyme-catalyzed conversion is effective for producing several types of structured phospholipase. However, most frequently employed catalytic procedures involve biphasic systems with organic solvents, which have a relatively large mass transfer resistance and are susceptible to solvent residues and environmental effects due to the hydrophobic nature of phospholipids. Therefore, the adoption of innovative, successful, and environmentally friendly enzyme-catalyzed conversion systems provides a new development route in the field of structured phospholipids processing. Several innovative catalytic reaction systems are discussed in this mini-review, including aqueous-solid system, mixed micelle system, water-in-oil microemulsion system, Pickering emulsion system, novel solvent system, three-liquid-phase system, and supercritical carbon dioxide solvent system. However, there is still a glaring need for a thorough examination of these systems for the enzymatic synthesis of structural phospholipids. In terms of the materials utilized, applicability, benefits and drawbacks, and comparative effectiveness of each system, this research establishes further conditions for the system's selection. To create more effective biocatalytic processes, it is still important to build green biocatalytic processes with improved performance. KEY POINTS: • The latest catalytic systems of phospholipase D are thoroughly summarized. • The various systems are contrasted, and their traits are enumerated. • Different catalytic systems' areas of applicability and limitations are discussed.

Solubility Modeling of Some Chlorophenols in Supercritical Carbon Dioxide

The basic information required to implement any supercritical processes is solubility. The solubility data is correlated with various models. For binary systems (solute-solvent), solubility data is limited in the literature, which makes it’s modelling essential. Equation of state (EoS) method is one of the best techniques to model solubility data. For EoS modelling to be implemented, critical properties of the solute and the solvent are essential but, the exact realistic properties are sparse for solutes. The present work deals with the modelling of the solubility of solid solutes in supercritical carbon dioxide solvent with and without critical properties of the solute. Redlich-Kwong (RK) EoS along with Kwak-Mansoori (KM) mixing rules is used for the solubility data modelling. In this work, three substituted phenols and supercritical carbon dioxide systems are considered for modelling. Finally, the correlating abilities of RK EoS along with KM mixing rules with and without critical properties of the solute are indicated in terms of the average absolute relative deviation percentage (AARD%) and Akaike information criterion (AIC).

Demonstration of direct ocean carbon capture using hollow fiber membrane contactors

The focus of membrane carbon capture to date has been primarily on point source capture, such as power plants and industrial capture. However, membrane technology can also play a role in negative emissions technology, such as direct air capture and direct ocean capture. Direct ocean capture has a few potential advantages over direct air capture, such as avoiding land use and coupling with offshore wind and offshore storage. The use and feasibility of hollow fiber membrane contactors (HFMCs) for direct ocean carbon capture with benign aqueous basic carbon dioxide solvents is assessed here through a multifaceted approach. A 1D HFMC model incorporates fluid dynamics and the chemical kinetics of both ocean water and aqueous sodium hydroxide solvent in order to simulate CO2 flux behavior in two flow configurations. Lab scale experiments of this system then guide a model refinement and validation process until experimental behaviors are predicted through computation. A preliminary technoeconomic assessment then uses computational and experimental results to estimate the carbon capture cost when the system is scaled to remove 0.98 Mtonnes CO2/year. Computational results suggest that higher seawater flow rates and temperatures relative to the sodium hydroxide solvent improve CO2 flux. The technoeconomic assessment suggests that HFMCs may only be cost-competitive if seawater pH is decreased at the membrane interface, thereby increasing the local concentration of dissolved carbon dioxide. These findings indicate that local pH swing on the seawater side will be necessary to feasibly remove carbon dioxide from seawater using HFMCs.

Two-dimensional ruthenium nanoparticles between graphite layers: The effect of reduction temperature

A mixture of graphite powder and ruthenium chloride (III) anhydrous was treated at 723 K under 0.3 MPa chlorine for 3 days, followed by reduction under 40 kPa of hydrogen for 1 h to produce ruthenium metal particles intercalated between graphite layers (Ru-GIC). The structures of ruthenium particles depended on the reduction temperatures. Sheet-like ruthenium particles with 1–3 nm thickness and 10 to several hundred nm width containing numerous irregularly shaped holes with round edge, were formed by reduction at 573 K. A Ru-GIC sample treated at 653 K possessed two-dimensional ruthenium nanosheets with hexagonal holes (straight lines intersect at an angle of 120°) in a similar range of thickness and width. On the other hand, Ru-GIC samples reduced at 773 and 823 K showed two-dimensional plate morphology with a thickness of 1–4 nm. In addition, ruthenium nanoparticles supported on the graphite surface (Ru/Gmix) were also prepared from a slurry of ruthenium chloride (III) hydrate and graphite powder by impregnation and hydrogen reduction. The ruthenium particles in Ru/Gmix were spherical at about 3.6 nm, and the reduction temperature did not affect their particles size. Both Ru-GIC and Ru/Gmix samples were evaluated for cinnamaldehyde (CAL) hydrogenation in supercritical carbon dioxide solvent at 323 K, and they were active to produce cinnamyl alcohol (COL) and hydrocinnamaldehyde (HAL). However, Ru-GIC samples showed higher COL selectivity than Ru/Gmix prepared at the same reduction temperature, and COL selectivity over Ru-GIC increased with the reduction treatments at 773 and 823 K.

Functionalized ionic liquids for CO2 capture under ambient pressure

ABSTRACT Ionic liquids (ILs) have been widely explored as alternative solvents for carbon dioxide (CO2) capture and utilization. However, most of these processes are under pressures significantly higher than atmospheric level, which not only levies additional equipment and operation costs, but also makes the large-scale CO2 capture and conversion less practical. In this study, we rationally designed glycol ether-functionalized imidazolium, phosphonium and ammonium ILs containing acetate (OAc–) or Tf2N– anions, and found these task-specific ILs could solubilize up to 0.55 mol CO2 per mole of IL (or 5.9 wt% CO2) at room temperature and atmospheric pressure. Although acetate anions enabled a better capture of CO2, Tf2N– anions are more compatible with alcohol dehydrogenase (ADH), which is a key enzyme involved in the cascade enzymatic conversion of CO2 to methanol. Our promising results indicate the possibility of CO2 capture under ambient pressure and its enzymatic conversion to valuable commodity.

Mechanism Study of Imidazole-Type Deep Eutectic Solvents for Efficient Absorption of CO2.

Deep eutectic solvents (DESs) are a new class of green solvents that exhibit unique properties in various process applications. In this regard, this study evaluated imidazole-type DESs as solvents for carbon dioxide (CO2) capture. A series of imidazole-type DESs with different ratios was prepared through one-step synthesis. The absorption capacity of CO2 in imidazole-type DESs was measured through weighing, and the effects of temperature, hydrogen bond acceptors, hydrogen bond donors, and water content were discussed. DESs absorbed the effects of CO2. Im-MEA (1:2) was selected to linearly fit lnη and 1/T using the Arrhenius equation under variable temperature conditions, and a good linear relationship was found. The results show the best absorption effect for Im-MEA (1:4). At 303.15 K and 0.1 MPa, the absorption capacity of Im-MEA (1:4) was as high as 0.323 g CO2/g DES; through five times of absorption-desorption after the cycle, the absorption capacity of DES was almost unchanged. Finally, the mechanism of CO2 absorption was studied using Fourier transform infrared and nuclear magnetic resonance spectroscopy. The absorption mechanism of imidazole-type DESs synthesized using imidazole salt and an amine-based solution was chemical absorption, and the reaction formed carbamate (-NHCOO) to absorb CO2.

A predictive group-contribution framework for the thermodynamic modelling of CO[formula omitted] absorption in cyclic amines, alkyl polyamines, alkanolamines and phase-change amines: New data and SAFT-[formula omitted] Mie parameters

A significant effort is under way to identify improved solvents for carbon dioxide (CO2) capture by chemisorption. We develop a predictive framework that is applicable to aqueous solvent + CO2 mixtures containing cyclic amines, alkyl polyamines, and alkanolamines. A number of the mixtures studied exhibit liquid–liquid phase separation, a behaviour that has shown promise in reducing the energetic cost of CO2 capture. The proposed framework is based on the SAFT-γ Mie group-contribution (GC) approach, in which chemical reactions are described via physical association models that allow a simpler, implicit, treatment of the chemical speciation characteristic of these mixtures. We use previously optimized group interaction parameters between some amine groups and water (Perdomo et al., 2021), and develop new group interactions for the cNH, cN, NH2, NH, N, cCHNH, and cCHN groups with CO2; a set of second-order group parameters are also developed to account for proximity effects in some alkanolamines. A combination of literature data and new experimental measurements for the absorption of CO2 in aqueous cyclohexylamine systems obtained in our current work, are used to develop and test the proposed models. The SAFT-γ Mie GC approach is used to predict the thermodynamics of selected mixtures, including ternary phase diagrams and mixing properties relevant in the context of CO2 capture. The current work constitutes a substantial extension of the range of aqueous amine-based solvents that can be modelled and thus offers the most comprehensive thermodynamically consistent platform to date to screen novel candidate solvents for CO2 capture.

Carbon Dioxide Solubility in Nonionic Deep Eutectic Solvents Containing Phenolic Alcohols.

Deep eutectic solvents (DES) are a new class of green solvents that have shown unique properties in several process applications. This study evaluates nonionic DES containing phenolic alcohols as solvents for carbon dioxide (CO2) capture applications. Potential phenolic alcohols and the molar ratio between DES constituents were preselected for experimental investigations based on the conductor-like screening model for realistic solvation (COSMO-RS). CO2 solubility was experimentally determined in two different DES, namely, L-menthol/thymol in 1:2 molar ratio and thymol/2,6-xylenol in 1:1 molar ratio, at various temperatures and pressures. CO2 solubility in the studied systems was higher than that reported in the literature for ionic DES and ionic liquids. This study demonstrates that nonionic DES containing phenolic alcohols can be excellent, inexpensive, and simple solvents for CO2 capture.

Comprehensively Explore Adsorption Capacity of Innovative Betaine-Based Deep Eutectic Solvents for Carbon Dioxide

Comprehensively Explore Adsorption Capacity of Innovative Betaine-Based Deep Eutectic Solvents for Carbon Dioxide

The Influence of Convection Heat Transfers for Vertical Mini-Tubes Using Solvent Carbon Dioxide and Porous Media at Supercritical Pressure

Porous media and solvent CO2 at supercritical pressure were investigated experimentally to study the effect of convection heat transfer in vertical mini-tubes. Mini-tubes diameter (5 and 8 mm) with medium porosity of 0.5 are proposed in experimental investigation. Experimental conditions consisted of bulk fluid, wall temperatures ranged from 33 to 55 oC, and 8 to 10 MPa of pressure. Reynolds number, Mass flow rate, and heat flux were 1750 to 21000, 0.5 to 4.5 Kg/h, and 3.25×104 to 1.1×105 W/m2 respectively. Some chemical additives like Ethanol, Chloroform, Acetone, Dimethyl sulfoxide, and Methanol were considered. A special focus was dedicated to studying the influence of heat flux, inlet temperature, and mass flow rate at measured values of wall and fluid bulk temperatures, and coefficients of local heat transfer for mini-tubes and porous media. A higher effect was noticed on the convection heat transfer by buoyancy and properties of the thermophysical variable of solvent CO2 in mini-tube at vertical position. However, when these results were compared with the controls (empty tube) shoewn dramatically different results. Heat transfer coefficient was bigger about 4 times when using the porous media tube compared with the empty type in the case of using a 5% of acetone solvent.

Development of novel wet sublimation cascade refrigeration system with binary mixtures of R744/R32 and R744/R290

The use of carbon dioxide (R744) in refrigeration systems is usually limited by its triple point temperature of −56.5 °C; an objective of this study was to extend the range of this natural refrigerant to include low-temperature applications. A novel wet sublimation cascade refrigeration system was developed using low-GWP mixtures of R744 with hydrocarbons (HCs) and hydrofluorocarbons (HFCs) as low-temperature refrigerants. With propane (HC-290) and difluoromethane (HFC-32) serving as solvents for solid carbon dioxide, temperatures as low as −72 °C were obtained in a closed cycle system with mixtures containing 67% CO2 by mass. Visualisation experiments were performed to illustrate the crystallisation of a supersaturated carbon dioxide solution. The excess solute was visible as clouding or crystals, depending on the saturation level of the solution. High heat transfer rates, up to 3465 W m–2K−1, were obtained in the sublimator/evaporator section, resulting in low wall superheat values, indicating potential industrial applicability of the carbon dioxide-based slurry-like fluid. The pressure–mole fraction and temperature–mole fraction diagrams were constructed to study the system parameters working with binary mixtures. Moreover, vapour pressures of the binary mixtures of R744/R290 and R744/R32 at the temperature of –72.5 °C were experimentally obtained.

Prediction of CO2 solubility in aqueous solutions of N, N-Diethyl ethanolamine (DEEA): A modified Kent-Eisenberg model approach

A tremendous increase in the carbon dioxide emissions over the last few decades has caused serious environmental concern. The research fraternity is working towards the discovery of novel solvents for carbon dioxide with greater removal efficiency. N, N-Diethyl ethanolamine (DEEA), a tertiary amine which can be prepared from renewable resources, is a potential absorbent for carbon dioxide removal. Determination of the equilibrium characteristics of the system plays a key role in the designing of industrial plants. In this work, the equilibrium solubility of CO2 in aqueous solutions of DEEA at different temperatures and CO2 partial pressures has been modeled using the modified Kent-Eisenberg model. The model predicted values were found to be in good agreement with the reported experimental data.

Green Chemistry Approach for Fabrication of Polymer Composites

Solvents are an inevitable part of industries. They are widely used in manufacturing and processing industries. Despite the numerous controlling measures taken, solvents contaminate our environment to a vast extent. Green and sustainable solvents have been a matter of growing interest within the research community over the past few years due to the increasing environmental concerns. Solvents are categorized as “green” based on their nonvolatility, nonflammability, availability, biodegradability and so on. The use of ionic liquids, super critical carbon dioxide and aqueous solvents for the fabrication of polymer composites is discussed in this review. The progress of utilizing solvent-free approaches for polymer composite preparation and efforts to produce new biobased solvents are also summarized.

Extraction of hemp seed using near-critical CO2, propane and dimethyl ether

Near-critical solvents carbon dioxide, propane and dimethyl-ether were used to extract lipids from cold-pressed hemp seed meal, hulls, and hearts. Extraction of meal yielded a low-fat marc that was fractionated by particle size into high-protein and high-fibre fractions. Supercritical CO2 processing was optimised by milling and sieving the meal to concentrate the oil and protein in the feed stream prior to extraction. DME was the most thorough solvent, co-extracting more water than CO2 and propane, which removed none. DME and propane both extracted over 90% of the available tocopherols from the hemp seed hearts although neither were particularly effective at phospholipid extraction.

Response Surface Methodology Towards Optimization of Calotropis Procera Essential Oil Extraction by Using Supercritical CO2

Aim: In this research, we aim to investigation on the extraction of essential oil from Calotropis Procera with the family name of Asclepiadaceae, by supercritical carbon dioxide (CO2) solvent. Objective: The comparison of the yield and chemical profile of the extracts achieved by this method with those resulted by the conventional Hydro distillation method. Methods: The extraction experiments were carried out in a bench-scale SC-CO2 unit. The effects of temperature, pressure, and extraction time on the oil yield are considered for investigation. The Response Surface Methodology (RSM) with Central Composite Design (CCD) was employed to optimize the process parameters of CO2 supercritical extraction (SCE) of the Calotropis Procera. In this experimental design, the design was required 19 experiments with eight (23) factorial points and five replications of the center. Results: Results showed that the data were sufficiently fitted into the second-order polynomial model. The extraction conditions, including pressure, temperature, and extraction time, were studied between 150-200 bar, 40-50 ºC, and 50-100 min, respectively. Conclusion: The optimal conditions are achieved as the temperature of 47.19ºC, the pressure of 172.2 bar, and time of 86 minutes with the retrieval rate of 31.39%.

Preparation and Structural Characterization of Platinum Nanosheets Intercalated between Graphite Powder with High Surface Area

Synthesis of platinum nanoparticles intercalated between layers of commercially available graphite powder samples possessing surface area values ranging from 20 to 750 m2 g-1 was attempted by the insertion of platinum chloride between the layers followed by hydrogen reduction. Platinum nanosheets with 1-4 nm thickness and 5-300 nm width and hexagonal holes were obtained for the graphite powder with 20 m2 g-1 independent of the platinum loadings (5, 10, and 15 wt%). Platinum nanosheets with the similar size (1-4 nm thickness and 5-300 nm width) and hexagonal holes were formed for graphite powder with 120 and 300 m2 g-1 with only 15 wt% platinum loading, but not for 5 and 10 wt% platinum loadings. Interestingly, for the graphite powder with higher surface area of 500 and 750 m2 g-1, platinum nanosheets were not formed. Platinum nanosheets intercalated between graphite samples were evaluated for cinnamaldehyde hydrogenation in supercritical carbon dioxide solvent. High cinnamyl alcohol selectivity was obtained for the platinum nanosheets intercalated between graphite layers having surface area of 20 m2 g-1; however, hydrocinnamaldehyde selectivity was high for the platinum nanosheets intercalated between graphite samples having surface area of 120 m2 g-1.

Solubility of carbon dioxide (CO2) in aqueous solution of 3-(dimethylamino)-1-propylamine (DMAPA)

The main objective of this study is to investigate the efficiency of 3-(Dimethylamino)-1-propylamine (DMAPA) as a solvent for carbon dioxide (CO2) capture. The solubility of CO2 in aqueous solutions of DMAPA was measured at (313.15 and 333.15) K and at a partial pressure of CO2 up to 275 kPa using the pressure-decay method. Measurements were performed at two concentrations of DMAPA (15 wt % and 30 wt %). DMAPA exhibited high CO2 loading when compared with other benchmark amines for CO2 absorption technology such as mono-ethanolamine (MEA) and piperazine (PZ). In this study, the highest CO2 loading recorded was 1.46 at 313.15 K at a CO2 partial pressure of 271 kPa. The experimental solubility data were correlated with the electrolyte-NRTL model, and the Redlich-Kwong (RK) equation of state was used for the estimation of the vapor phase fugacity coefficients at equilibrium. Excess enthalpy (HE) for DMAPA-water binary system was measured using a C80 flow calorimeter at (313.15 and 333.15) K. Binary NRTL parameters for DMAPA/H2O were regressed from the excess enthalpy (HE) data of the DMAPA-water system; and some other parameters such as the molecule-ion pair parameters, equilibrium constants, etc. were regressed using vapor-liquid equilibrium (VLE) data. Finally, the Gibbs-Helmholtz equation was used to predict the heat of absorption of CO2 solubility in the amine solution based on solubility data.