Influence of the mesoconfining solid on gas oversolubility in nanoliquids

Soybean Oil Treatment Using the Dissolving Curve Equation of Hydrogen

The solubility of hydrogen in n-hexane was determined using a homemade reactor. The solubility of hydrogen in soybean oil was established using the Peng-Robinson (PR) equation of state and the van der Waals mixing rule. The curve equation established a linear relationship between the solubility of hydrogen in oil and the number of moles of hydrogen in the reactor. Under the optimal temperature and catalyst, the relationship between the hydrogen consumption of the hydrogenation of oil and fat and the TFAs formed in the oil was determined. When the reaction pressure exceeded 3.0 MPa, the hydrogenation of oil was consumed. The amount of hydrogen, the rate of hydrogenation, and the change in the TFAs all stabilized. Therefore, the pressure of the general hydrogenation reaction should not exceed 3.0 MPa. This result provides a quick and simple method for controlling TFAs in oils and fats for industrial applications.

Molecular Dynamics Study on CO2 Storage in Water-Filled Kerogen Nanopores in Shale Reservoirs: Effects of Kerogen Maturity and Pore Size

CO₂ sequestration in shale reservoirs is an economically viable option to alleviate carbon emission. Kerogen, a major component in the organic matter in shale, is associated with a large number of nanopores, which might be filled with water. However, the CO₂ storage mechanism and capacity in water-filled kerogen nanopores are poorly understood. Therefore, in this work, we use molecular dynamics simulation to study the effects of kerogen maturity and pore size on CO₂ storage mechanism and capacity in water-filled kerogen nanopores. Type II kerogen with different degrees of maturity (II-A, II-B, II-C, and II-D) is chosen, and three pore sizes (1, 2, and 4 nm) are designed. The results show that CO₂ storage mechanisms are different in the 1 nm pore and the larger ones. In 1 nm kerogen pores, water is completely displaced by CO₂ due to the strong interactions between kerogen and CO₂ as well as among CO₂. CO₂ storage capacity in 1 nm pores can be up to 1.5 times its bulk phase in a given volume. On the other hand, in 2 and 4 nm pores, while CO₂ is dissolved in the middle of the pore (away from the kerogen surface), in the vicinity of the kerogen surface, CO₂ can form nano-sized clusters. These CO₂ clusters would enhance the overall CO₂ storage capacity in the nanopores, while the enhancement becomes less significant as pore size increases. Kerogen maturity has minor influences on CO₂ storage capacity. Type II-A (immature) kerogen has the lowest storage capacity because of its high heteroatom surface density, which can form hydrogen bonds with water and reduce the available CO₂ storage space. The other three kerogens are comparable in terms of CO₂ storage capacity. This work should shed some light on CO₂ storage evaluation in shale reservoirs.

Enhancing Gas Solubility in Nanopores: A Combined Study Using Classical Density Functional Theory and Machine Learning

Geometrical confinement has a large impact on gas solubilities in nanoscale pores. This phenomenon is closely associated with heterogeneous catalysis, shale gas extraction, phase separation, etc. Whereas several experimental and theoretical studies have been conducted that provide meaningful insights into the over-solubility and under-solubility of different gases in confined solvents, the microscopic mechanism for regulating the gas solubility remains unclear. Here, we report a hybrid theoretical study for unraveling the regulation mechanism by combining classical density functional theory (CDFT) with machine learning (ML). Specifically, CDFT is employed to predict the solubility of argon in various solvents confined in nanopores of different types and pore widths, and these case studies then supply a valid training set to ML for further investigation. Finally, the dominant parameters that affect the gas solubility are identified, and a criterion is obtained to determine whether a confined gas-solvent system is enhance-beneficial or reduce-beneficial. Our findings provide theoretical guidance for predicting and regulating gas solubilities in nanopores. In addition, the hybrid method proposed in this work sets up a feasible platform for investigating complex interfacial systems with multiple controlling parameters.

Confined benzene within InOF-1: contrasting CO2 and SO2 capture behaviours

Benzene confinement enhances the CO₂ capture while decreases the SO₂ capture within InOF-1 due to the competition among molecules for the preferential adsorption sites. Pore channel view of CO2Bz@InOF-1b (left) and SO2⋯Bz@InOF-1b (right) systems.

CO2 capture enhancement for InOF-1: confinement of 2-propanol

The confinement of small amounts of i-PrOH demonstrated and enhanced CO₂ capture for InOF-1 as a result of the bottleneck effect and the formation of essential hydrogen bonds.

Confined toluene within InOF-1: CO2 capture enhancement

The confinement of small amounts of toluene demonstrated an enhanced CO₂ capture for InOF-1 as a result of a bottleneck effect and synergistic interactions.

Enhanced Oxygen Solubility in Metastable Water under Tension

Despite its relevance in numerous natural and industrial processes, the solubility of molecular oxygen has never been directly measured in capillary-condensed liquid water. In this article, we measure oxygen solubility in liquid water trapped within nanoporous samples, in metastable equilibrium with a subsaturated vapor. We show that solubility increases two fold at moderate subsaturations (relative humidity ∼0.55). This evolution with relative humidity is in good agreement with a simple thermodynamic prediction using properties of bulk water, previously verified experimentally at positive pressure. Our measurement thus verifies the validity of this macroscopic thermodynamic theory to strong confinement and large negative pressures, where significant nonidealities are expected. This effect has strong implications for important oxygen-dependent chemistries in natural and technological contexts.

Confined methanol within InOF-1: CO2 capture enhancement

The CO₂ capture in InOF-1 was enhanced by confining small amounts of MeOH. DFT calculations coupled with forcefield based-MC simulations revealed that such an enhancement is due to an increase of the degree of confinement.

Confinement of alcohols to enhance CO2 capture in MIL-53(Al)

CO₂ capture of MIL-53(Al) was enhanced by confining small amounts of MeOH and i-PrOH within its micropores.

Enhanced H2 uptake in solvents confined in mesoporous metal-organic framework

Hydrogen uptake at 298 K and 30 bar in hybrid sorbents consisting of n-hexane confined in MIL-101 is found to be 22 times larger than in sole n-hexane. The enhanced solubility in MIL-101, found to be 3 times larger than in mesoporous silica of similar pore size, highlights the key roles played by surface chemistry and accessible surface area.