Hybrid Solvent Research Articles

Hybrid solvent loop CO2 capture process for zero-emission hydrogen production

Natural gas reforming with CO2 capture is expected to play a crucial role in producing low-carbon hydrogen under the net-zero emission scenario. This work focuses on optimizing the CO2 capture processes for zero-emission hydrogen production, targeting an ultra-high CO2 capture ratio of 99.9 % from the shifted syngas. We present a novel hybrid solvent loop CO2 capture process that enhances capture efficiency by overcoming the inherent trade-off between CO2 absorption kinetics and capacity in conventional processes. This is achieved by utilizing two independent solvent loops, each operating within its optimal performance range. In the lower section of the absorber, a high-capacity solvent, aqueous potassium carbonate, is used to leverage the high CO2 partial pressure. In the upper section, a fast-kinetic solvent, aqueous monoethanolamine, is employed to reduce CO2 concentration to 100 ppm. The conventional process, split-flow process with a multi-pressure stripper, and the hybrid solvent loop process are modeled in Aspen Plus® and compared. Our results demonstrate that the proposed hybrid solvent loop configuration outperforms conventional methods, significantly reducing the CO2 regeneration duty by 25 % and total equivalent work by 16 %. This process enhances the feasibility of low-carbon hydrogen production and supports the goal of achieving net-zero emissions.

Thermodynamic modeling and process evaluation of advanced ionic liquid-based solvents for CO2/CH4 separation

Carbon capture technology is a prospective strategy to address the increasing concentration of CO2 in the atmosphere, with the core challenge of developing new cost-effective processes. In this work, the energy analysis and economic evaluation were conducted based on rigorous thermodynamic models and the process simulation results of a novel chemical absorption-dominated hybrid solvent which consists of functional ionic liquid of choline triazole ([Cho][Triz]) and sulfolane (TMS) to separate CO2 from shale gas. The solubility of CO2 and CH4 in different solvents were calculated using phase equilibrium model including the NRTL activity coefficient equation, the RK equation of state, chemical reaction equilibrium equations, and the mass balance equation. The physical properties of the ionic liquid-based solvent systems were calculated with empirical equations which was corrected using experimental data. The results obtained from the thermodynamic models exhibited good agreement with experimental data. Subsequently, the established models and the parameters obtained were embedded into Aspen Plus for further analysis. The total CO2 capture energy consumption of 1.65 GJ·t−1 CO2 and the cost of 48.07 $·t−1 CO2 were achieved using the new solvent when the mass fraction of IL was 60 wt%. Compared with the commercial 30 wt% MDEA carbon capture process, it reduced the energy consumption and economic cost of 64.16 % and 45.59 %, respectively.

Removal of Carbon Dioxide and Hydrogen Sulfide from Natural Gas Using a Hybrid Solvent of Monoethanolamine and N-Methyl 2-Pyrrolidone.

The main goal of traditional methods for sweetening natural gas (NG) is to remove hydrogen sulfide (H2S) and significantly lower carbon dioxide (CO2). However, when NG processes are integrated into the carbon capture and storage (CCS) framework, there is potential for synergy between these two technologies. A steady-state model utilizing a hybrid solvent consisting of N-methyl-2-pyrrolidone (NMP) and monoethanolamine (MEA) has been developed to successfully anticipate the CO2 and H2S capture process from NG. The model was tested against important variables affecting process performance. This article specifically explores the impact of operational parameters such as lean amine temperature, absorber pressure, and amine flow rate on the concentrations of CO2 and H2S in the sweet gas and reboiler duty. The result shows that hybrid solvents (MEA + NMP) perform better in removing acid gases and reducing reboiler duty than conventional chemical solvent MEA. The primary purpose is to meet product requirements while consuming the least energy possible, which is in line with any process plant's efficiency goals.

Machine learning models for the density and heat capacity of ionic liquid–water binary mixtures

Ionic liquids (ILs), because of the advantages of low volatility, good thermal stability, high gas solubility and easy recovery, can be regarded as the green substitute for traditional solvent. However, the high viscosity and synthesis cost limits their application, the hybrid solvent which combining ILs together with others especially water can solve this problem. Compared with the pure IL systems, the study of the ILs–H2O binary system is rare, and the experimental data of corresponding thermodynamic properties (such as density, heat capacity, etc.) are less. Moreover, it is also difficult to obtain all the data through experiments. Therefore, this work establishes a predicted model on ILs-water binary systems based on the group contribution (GC) method. Three different machine learning algorithms (ANN, XGBoost, LightBGM) are applied to fit the density and heat capacity of ILs–water binary systems. And then the three models are compared by two index of MAE and R2. The results show that the ANN-GC model has the best prediction effect on the density and heat capacity of ionic liquid-water mixed system. Furthermore, the Shapley additive explanations (SHAP) method is harnessed to scrutinize the significance of each structure and parameter within the ANN-GC model in relation to prediction outcomes. The results reveal that system components (XIL) within the ILs–H2O binary system exert the most substantial influence on density, while for the heat capacity, the substituents on the cation exhibit the greatest impact. This study not only introduces a robust prediction model for the density and heat capacity properties of IL-H2O binary mixtures but also provides insight into the influence of mixture features on its density and heat capacity.

Reactive regeneration in novel hybrid solvent: Achieving dual objectives of H2S conversion and absorbent regeneration

In this work, we developed a composite solution (FILs/DFP) using ionic liquids (FILs) and 4-formylmorpholine (DFP) for natural gas desulfurization. Among these, [TND-C][Tf2N]/DFP exhibited an impressive H2S uptake of 3.65 mol/mol and H2S/CO2 selectivity of 25 at 30 °C and 1 bar. The 1H NMR, FTIR, and DFT calculations revealed that the dense hydrogen bonding network and the active sites of tertiary amines in FILs/DFP were the main factors for the efficient uptake of H2S. Furthermore, we propose a viable reaction regeneration strategy at room temperature, successfully addressing the challenges of absorber regeneration, the catalytic activity of the FILs remained above 95 % even after six cycles. Overall, this strategy eliminates the high energy losses of H2S desorption and allows for the recycling of FILs with minimal energy consumption. This simultaneously achieving dual objectives of H2S conversion and absorbent regeneration process shows promising applications in natural gas desulphurization.

Reconstructing Inorganic‐Rich Interphases by Nonflammable Electrolytes for High‐Voltage and Low‐Temperature LiNi0.5Mn1.5O4 Cathodes

AbstractCobalt‐free and spinel LiNi0.5Mn1.5O4 (LNMO) cathodes commonly suffer from undesirable solvent decomposition, serious transition‐metal dissolution, and unstable cathode electrolyte interphase (CEI) layers, incurring rapid capacity decay at high voltages and low temperatures. Herein, these issues are well addressed by utilizing fluorinated solvents with a low coordination number and ethyl propionate with a low melting point. A Li2CO3/LiF‐rich heterostructured CEI layer, which possesses good electron blocking capability of LiF, fast Li+ transport kinetics of Li2CO3 and good mechanical stability, is generated by the synergistic decomposition of hybrid solvents. The robust, homogeneous, and well‐balanced CEI layers subsequently prevent catalyzed parasitic side reactions, prohibit transition‐metal dissolution, and ensure fast interfacial reaction kinetics crossover to the LNMO cathode, thus improving its cycling stability. Consequently, the LNMO cathode delivers a high‐capacity retention of 95.8% over 500 cycles at 25 °C and 97.5% after 180 cycles at −20 °C. This work provides an encouraging alternative to design the high‐voltage and low‐temperature electrolyte for pushing the ongoing research to stabilize Co‐free LNMO materials toward practical applications.

“Co-solvent-in-salt” electrolyte for boosting Zn anode reversibility

The “solvent-in-salt” electrolyte is considered as a technology of significance for rechargeable Zn metal batteries due to its non-flammable, moisture-tolerant and electrochemical stable merits. Particularly, the “co-solvent-in-salt” electrolyte with dual-solvent of water and acetonitrile is developed in this work. It possesses both the advantages of high-concentration and aqueous/organic hybrid solvent, such as, low cost, low water content, high concentration and impressive ion conductivity. The corresponding modulated solvation structure and chemical environmental in the optimized electrolyte system contribute to suppress the side reactions (hydrogen evolution reaction (HER), Zn corrosion, dendrites growth) significantly. And they further improve the homogeneous Zn deposition, the plating/stripping reversibility (∼99.8 %) and the stability (∼2900 h) of Zn metal anode even in the Zn//NH4V4O10 full battery (500 cycles).

Hybrid Co‐Solvent‐Induced High‐Entropy Electrolyte: Regulating of Hydrated Zn2+ Solvation Structures for Excellent Reversibility and Wide Temperature Adaptability

AbstractAs a new generation of lithium‐ion battery alternative, aqueous zinc (Zn) ion batteries (ZIBs) garner tremendous interests for future energy storage application owing to their inherent incombustible, nontoxic, and low‐cost features. However, their practical utilization is hampered by the electrolyte freezing at subzero conditions. In this study, a novel high‐entropy (HE) electrolyte fabricated is presented with hybrid solvents to mitigate electrolyte freezing at low temperatures, restrain calendar corrosion, and boost Zn‐ion transfer kinetics. Specifically, the isovolumetric combined ethyl acetate, ethylene glycol, and dimethyl sulfoxide as solvent components not only induce a reconfiguration of hydrogen bonding, but also alter the solvation sheath of Zn ions within the HE electrolyte environment. This synergistic coupling of hybrid co‐solvents effectively harnesses the features of individual solvent additive and facilitates the remarkable advantages on cycling reversibility, especially in the low‐temperature conditions. Benefiting from the anti‐freezing and solvation structure regulation features, Zn symmetrical batteries equipped with HE electrolytes can work over 2500 h in low zinc salt concentration (1 m) at various temperatures. This work provides a facile modulation strategy to achieve the HE electrolyte, promoting the practical application and commercialization of advanced ZIBs with wide‐temperature adaptability.

A novel synergistic intensification method for CO2 absorption by metal salt and task-specific ionic liquids hybrid solvent in microchannel reactor

A novel metal salt-promoting mass transfer intensification method for CO2 absorption into task-specific ionic liquids aqueous solution was proposed. The mass transfer intensification and intrinsic mechanisms of different concentrations of metal salts (NaBF4, KBF4, KCl, and CuCl2) with task-specific ionic liquids (1-aminopropyl-3-methylimidazolium tetrafluoroborate [Apmim] [BF4]) aqueous solutions for CO2 capture process were visually investigated using a microchannel reactor. The results showed that adding metal salts could remarkably enhance the interaction between metal cations and ionic liquid anions, thereby decreasing the interaction between anions and cations within the ionic liquid molecules and promoting the chemical reaction between ionic liquid cations and CO2. Under the condition of the same salt concentration, the addition of KBF4 has more obvious enhancement for mass transfer in CO2 absorption process. The mass transfer coefficient increases as the gas-liquid phase flow rate rise under slug flow condition. In addition, based on the effects of metal salt concentration, absorbent density, and gas-liquid phase flow rate on the CO2 volumetric mass transfer coefficient kLa, a new correlation for predicting the volumetric mass transfer coefficient of CO2 absorption into the hybrid solvent in microchannel reactor was proposed and validated.

Enhancement of Cu2ZnSn(S, Se)4 device performance using an IPA/MOE hybrid solvent system in ambient air.

In this work, a mixed precursor solvent system comprising isopropyl alcohol (IPA) and 2-methoxy ethanol (MOE) is introduced for the fabrication of Cu2ZnSn(S, Se)4 (CZTSSe) thin films under ambient conditions. The effects of different IPA/(MOE + IPA) ratios on the characteristics of CZTSSe films and the corresponding devices were investigated. Our research results indicate that the addition of IPA enhances the wettability of Cu-Zn-Sn-S precursor solution on the substrate, reduces Sn loss in the film during high-temperature annealing, and diminishes band tail states. Additionally, adding IPA leads to effective enlargement of grain size, improved crystallinity, and enhanced light absorption. However, excessive content of IPA negatively impacts CZTSSe film properties and the device's performance. Notably, when substituting 20% of MOE with IPA, the short-circuit current density (JSC) increased from 30.84 mA cm-2 to 35.55 mA cm-2 in the resulting CZTSSe device, and the efficiency improved from 9.19% to 10.63%. This work provides a new method of a solvent system for preparing efficient kesterite-based solar cells.

Binary mixture of subcritical water and acetone: a hybrid solvent system towards the production of lignin nanoparticles

A hybrid solvent system based on binary subcritical water/acetone mixtures demonstrates production of uniform lignin nanoparticles while reducing the dependence on high volumes of organic solvent.

Hybrid Solvent Retention Capacity (SRC) to predict Australian soft wheat cookie quality

The Solvent Retention Capacity (SRC) method has been widely used in evaluating soft wheat quality elsewhere but not in Australia. This paper studies the potential of applying SRC to predict the Australian soft wheat quality in sugar snap cookies, which the Indonesian mills value. The cost-effective hybrid SRC method improves efficiency and repeatability in general by replacing the manual shaking mechanism with a programable multitube vortex shaker. The hybrid SRC method helps to reduce work health and safety risks by eliminating manual tube shaking steps. The collaborative laboratory study is conducted with two Indonesian mills and compared against SRC measured by the hybrid and automatic SRC methods. All SRC values measured using the hybrid SRC method are significantly correlated with those measured with manual and automatic SRC methods: SRC water (r = 0.8–1.0, p < 0.0001); sucrose (r = 0.9, p < 0.0001); sodium carbonate (r = 0.9, p < 0.0001); and lactic acid (r = 0.7–0.8, p < 0.01). Among the four SRC solvents, considering the SRC water is highly effective in discriminating hard and soft wheat, the high correlations between different laboratories, the relatively smaller standard deviation across laboratories and storage time and temperature at 22 °C and the significant correlation with cookie spread, it could be the best predictor of Australian soft wheat quality. Overall, the hybrid SRC method could be helpful in the Australian soft wheat breeding program, especially in the early-stage selection of soft wheat cultivars. The cookie spread negatively correlates with Rapid Viscosity Analyser peak viscosity (r = −0.8, p < 0.01), suggesting Australian soft wheat targets a lower pasting property for a better cookie performance. The SRC values of flour samples from four different soft wheat cultivars are affected by storage temperature at 22 °C and 32 °C over 12 months with inconsistent trends. The flour samples stored at various temperatures across 0, 1, 3, 6 and 12 moths, particularly those kept at a higher temperature, have more variability in their SRC values and higher uncertainty, which must be accounted for when comparing results between different laboratories. A standard SRC range will be established in collaboration with the Indonesian mills to categorise the Australian soft wheat quality suitable for the Indonesian market.

Preparation of ionic liquids amine hybrid solvents, characterization for CO2 absorption, and kinetic performance

The thermo-physical characteristics of an ionic liquid-amine hybrid solvent were studied in this work as a result of its potential use in the CO2 absorption process. The hybrid solvents were developed by mixing 30 wt% MDEA with ionic liquid at different concentrations of 5 wt%, 10 wt%, 15 wt% and 20 wt%. Three imidazolium-based ILs were investigated: 1-butyl-3-methylimidazolium dicyanamide [bmim][DCA], 1-butyl-3-methylimidazolium acetate [bmim][Ac] and 1-butyl-3-methylimidazolium trifluoromethanesulfonate [bmim][TfO. Aqueous ionic liquid-amine hybrid solvent's density, surface tension, refractive index, viscosity and were studied between 25 °C and 70 °C with a regular interval of 5 °C. Whereas the influence of temperature on viscosity is negligible beyond 65 °C and the influence of temperature changed certain physicochemical properties. Furthermore, high-pressure solubility tests were conducted at a fixed temperature of 30 °C to determine the solubility of CO2 in hybrid media at pressures ranging from 2 bar to 50 bar. The results showed that the CO2 solubility of the different ionic liquid-amine hybrid systems decreases in the following sequence: [bmim][TfO] + MDEA > [bmim][DCA] + MDEA > [bmim][Ac] + MDEA. It was also found out that the optimum concentration of ionic liquids in the solution is 10 wt%. The kinetics study of the hybrid solvents was studied as a function of concentration, and experimentally determined that 10 wt% [bmim][TfO] exhibited the fast CO2 absorption kinetics. The kinetics performance study was further conducted as a function of pressure, and the highest absorption rate was recorded at 50 bar as expected. Overall, the addition of ionic liquids was verified to improve the CO2 absorption and thus it was reported that ionic liquid-amine hybrid solvent is an auspicious solvent for CO2 removal in the future.

Bound ion effects: Using machine learning method to study the kinesin Ncd’s binding with microtubule

Drosophila Ncd proteins are motor proteins that play important roles in spindle organization. Ncd and the tubulin dimer are highly charged. Thus, it is crucial to investigate Ncd-tubulin dimer interactions in the presence of ions, especially ions that are bound or restricted at the Ncd-tubulin dimer binding interfaces. To consider the ion effects, widely used implicit solvent models treat ions implicitly in the continuous solvent environment without focusing on the individual ions’ effects. But highly charged biomolecules such as the Ncd and tubulin dimer may capture some ions at highly charged regions as bound ions. Such bound ions are restricted to their binding sites; thus, they can be treated as part of the biomolecules. By applying multiscale computational methods, including the machine-learning-based Hybridizing Ions Treatment-2 program, molecular dynamics simulations, DelPhi, and DelPhiForce, we studied the interaction between the Ncd motor domain and the tubulin dimer using a hybrid solvent model, which considers the bound ions explicitly and the other ions implicitly in the solvent environment. To identify the importance of treating bound ions explicitly, we also performed calculations using the implicit solvent model without considering the individual bound ions. We found that the calculations of the electrostatic features differ significantly between those of the hybrid solvent model and the pure implicit solvent model. The analyses show that treating bound ions at highly charged regions explicitly is crucial for electrostatic calculations. This work proposes a machine-learning-based approach to handle the bound ions using the hybrid solvent model. Such an approach is not only capable of handling kinesin-tubulin complexes but is also appropriate for other highly charged biomolecules, such as DNA/RNA, viral capsid proteins, etc.

A Readily Achieved Potentiostatic Method in Density Functional Theory Calculation for Improved Prediction of the Performance for Electrocatalytic Nitrogen Reduction Reaction.

Accurate prediction of the catalytic performance of nitrogen reduction reaction catalysts based on density functional theory (DFT) calculation is of great significance for developing catalytic materials for nitrogen fixation. However, the applied electrode potential induced the fixation of Fermi level and solvation effect are commonly ignored in the current computational hydrogen electrode method, which leads to the large deviation between the calculation predicted limit potential and the experimentally measured limit potential. In this work, the simple external iteration method is proposed to simulate the Fermi level of the catalysts that are fixed by the applied electrode potential, along with the hybrid solvent model to describe the strong interaction, such as hydrogen bond, between the solvent molecules and the intermediates. This method allowed the theoretical and experimental limit potentials to be in good agreement, indicating the significant effect of the electrode potential and solvation in the DFT calculation. These results will guide the calculation-based prediction of other reaction systems in the field of electrocatalysis.

Non-Nucleophilic Electrolytes with Non-Fluorinated Hybrid Solvents for Long-Life Magnesium Metal Batteries

Growing energy demands and the widespread of renewable power sources call for high-energy storage systems beyond lithium-ion batteries (LIBs). Rechargeable magnesium batteries (RMBs) are high-energy, safer, and more cost-effective alternatives to LIBs and lithium metal batteries (LMBs) thanks to Mg’s high volumetric capacity (3832 mAh cm-3)1, low theoretical potential (-2.37 V vs SHE)2 and earth-abundance3. Non-nucleophilic and non-fluorinated compounds are the most important class of materials to enable sustainable rechargeable magnesium (Mg) batteries, however, they suffer from poor stability due to the formation of unstable solid-electrolyte-interphase (SEI).4 Here, we design a hybrid-solvent electrolyte by dispersing a non-nucleophilic solution in a non-fluorinated weakly-coordinating solvent to prevent parasitic reactions and form stable SEI. This strategy significantly improved the cycle life of the Mg anode from 24 to 4000 hours (in Mg-Mg symmetric cells) and realized a stable cycle life of Mg-Mo6S8 full cells for more than 2300 hours with an average CE of 99.96%. The non-fluorinated weakly-coordinating solvent suppressed uneven Mg growth and contributed to the formation of polymeric SEI, which filled the cracks of pristine SEI, preventing side reactions and passivation. This strategy revealed the critical role of weakly-coordinating solvents in stabilizing Mg anode for reversible Mg batteries.

Hybrid solvents based on ionic liquids/deep eutectic solvents for CO2 separation

Hybrid solvents based on ionic liquids/deep eutectic solvents for CO2 separation

Engineered Highly Porous Polyvinyl Alcohol Hydrogels with Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and Graphene Nanosheets for Musculoskeletal Tissue Engineering: Morphology, Water Sorption, Thermal, Mechanical, Electrical Properties, and Biocompatibility.

Electroactive composite materials are very promising for musculoskeletal tissue engineering because they can be applied in combination with electrostimulation. In this context, novel graphene-based poly(3-hydroxybutyrate-co-3-hydroxyvalerate)/polyvinyl alcohol (PHBV/PVA) semi-interpenetrated networks (semi-IPN) hydrogels were engineered with low amounts of graphene (G) nanosheets dispersed within the polymer matrix to endow them with electroactive properties. The nanohybrid hydrogels, obtained by applying a hybrid solvent casting-freeze-drying method, show an interconnected porous structure and a high water-absorption capacity (swelling degree > 1200%). The thermal characterization indicates that the structure presents microphase separation, with PHBV microdomains located between the PVA network. The PHBV chains located in the microdomains are able to crystallize; even more after the addition of G nanosheets, which act as a nucleating agent. Thermogravimetric analysis indicates that the degradation profile of the semi-IPN is located between those of the neat components, with an improved thermal stability at high temperatures (>450 °C) after the addition of G nanosheets. The mechanical (complex modulus) and electrical properties (surface conductivity) significantly increase in the nanohybrid hydrogels with 0.2% of G nanosheets. Nevertheless, when the amount of G nanoparticles increases fourfold (0.8%), the mechanical properties diminish and the electrical conductivity does not increase proportionally, suggesting the presence of G aggregates. The biological assessment (C2C12 murine myoblasts) indicates a good biocompatibility and proliferative behavior. These results reveal a new conductive and biocompatible semi-IPN with remarkable values of electrical conductivity and ability to induce myoblast proliferation, indicating its great potential for musculoskeletal tissue engineering.

Exergy-based sustainability analysis of biogas upgrading using a hybrid solvent (imidazolium-based ionic liquid and aqueous monodiethanolamine)

Energy may be generated in large quantities from fossil fuels, but this comes with environmental concerns. Thus, renewable resources like biogas, comprising carbon dioxide and methane, should be used alone or in combination with fossil fuels to mitigate the environmental footprints of energy generation systems. In this study, a new concept of hybrid solvent was presented, which combines 1-octyl-3-methylimidazolium tetrafluoroborate with aqueous mono diethanolamine for biogas upgrading process to provide high purity (≥ 99 wt%) and recovery (≥ 99 wt%) of biomethane. The process was simulated in ASPEN Plus® V.11. The thermodynamic framework was validated against experimental data, and rigorous regression was conducted to obtain binary parameters. To establish the efficacy of the suggested hybrid solvent, three scenarios were studied by altering the concentration of ionic liquid (5–20 wt%) linked with amine and compared to aqueous mono diethanolamine as the base case (50 wt%). The results showed that a hybrid solvent with 5 wt% 1-octyl-3-methylimidazolium tetrafluoroborate could increase CH4 purity to 99% (mol%). The hybrid solvent led to an energy saving of 64.94% compared to the amine-based system. Thermodynamic irreversibilities showed that 5 wt% 1-octyl-3-methylimidazolium tetrafluoroborate improved exergy efficiency by 54% over the amine-based procedure. Environmentally, the hybrid solvent system also achieved a higher capture rate (99%) and lower emissions (0.017 kW/kmol). Comparing the economic prospects, 5 wt% 1-octyl-3-methylimidazolium tetrafluoroborate saved 56% on total capital cost, making it competitive from an investment perspective.

How Does Nanostructure in Ionic Liquids and Hybrid Solvents Affect Surfactant Self-Assembly?

Ionic liquids (ILs) have recently emerged as novel classes of solvents that support surfactant self-assembly into micelles, liquid crystals, and microemulsions. Their low volatility and wide liquid stability ranges make them attractive for many diverse applications, especially in extreme environments. However, the number of possible ion combinations makes systematic investigations both challenging and rare; this is further amplified when mixtures are considered, whether with water or other H-bonding components such as those found in deep eutectics. In this Perspective we examine what factors determine amphiphilicity, solvophobicity and solvophilicity, in ILs and related exotic environments, in what ways these differ from water, and how the underlying nanostructure of the liquid itself affects the formation and structure of micelles and other self-assembled materials.