High-pressure Intrusion Research Articles

High-pressure intrusion of double salt aqueous solution in pure silica chabazite: searching for cation selectivity

Heterogeneous lyophobic systems (HLSs), i.e. systems composed of a nanoporous solid and a non-wetting liquid, have attracted much attention as promising candidates for innovative mechanical energy storage and dissipation devices. In this work, a new HLS based on a pure silica chabazite (Si-CHA) and a ternary electrolyte solution (KCl + CaCl2) is studied from porosimetric and crystallographic points of view. The combined approach of this study has been fundamental in unravelling the properties of the system. The porosimetric experiments allowed the determination of the energetic behaviour, while high-pressure in situ crystallographic analyses helped elucidate the mechanism of intrusion. The results are compared with those obtained for systems involving the same zeolite but intruded with solutions containing only single salts (CaCl2 or KCl). The porosimetric results of the three Si-CHA systems intruded by simple and complex electrolyte solutions (KCl 2 M, CaCl2 2 M and the mixture KCl 1 M + CaCl2 1 M) suggest that the intrusion pressure is mainly influenced by the nature of the cations. The CaCl2 2 M solution shows the highest intrusion pressure and KCl 2 M the lowest, whereas the mixture KCl 1 M + CaCl2 1 M is almost in the middle. These differences are probably related to the higher hydration enthalpy and Gibbs energy of Ca2+ compared with those of K+. It has been demonstrated that partial ion desolvation is needed to promote the penetration of the species, and a higher solvation energy requires higher pressure. The `intermediate' value of intrusion pressure shown by the complex electrolyte solution arises from the fact that, statistically, the second/third solvation cation shells can be assumed to be partially shared between K+ and Ca2+. The stronger interaction of Ca2+ with H2O molecules thus also influences the desolvation of K+, increasing the pressure needed to activate the process compared with the pure KCl 2 M solution. This is confirmed by the structural investigation, which shows that at the beginning of intrusion only K+, Cl− and H2O penetrate the pores, whereas the intrusion of Ca2+ requires higher pressure, in agreement with the hydration enthalpies of the two cations.

Structure influence on high-pressure water intrusion in pure silica zeolites

The high-pressure intrusion–extrusion of water in ITE-, CDO- and MTF-type zeosils has been studied. The relationship between the zeosil structure, particularly, pore size and topology, and intrusion-extrusion characteristics is discussed.

Bimetallic Zeolitic Imidazole Frameworks for Improved Stability and Performance of Intrusion-Extrusion Energy Applications.

Hydrophobic flexible zeolitic imidazole frameworks (ZIFs) represent reference microporous materials in the area of mechanical energy storage, conversion, and dissipation via non-wetting liquid intrusion-extrusion cycle. However, some of them exhibit drawbacks such as lack of stability, high intrusion pressure, or low intrusion volume that make them non-ideal materials to consider as candidates for real applications. In this work, we face these limitations by exploiting the hybrid ZIF concept. Concretely, a bimetallic SOD-like ZIF consisting of Co and Zn ions was synthesized and compared with Co-ZIF (ZIF-67) and Zn-ZIF (ZIF-8) showing for the first time that the hybrid ZIF combines the good stability of ZIF-8 with the higher water intrusion volume of ZIF-67. Moreover, it is shown that the hybrid-ZIF approach can be used to tune the intrusion/extrusion pressure, which is crucial for technological applications.

Mechanism of Water Intrusion into Flexible ZIF-8: Liquid Is Not Vapor.

Zeolitic Imidazolate Frameworks (ZIF) find application in storage and dissipation of mechanical energy. Their distinctive properties linked to their (sub)nanometer size and hydrophobicity allow for water intrusion only under high hydrostatic pressure. Here we focus on the popular ZIF-8 material investigating the intrusion mechanism in its nanoscale cages, which is the key to its rational exploitation in target applications. In this work, we used a joint experimental/theoretical approach combining in operando synchrotron experiments during high-pressure intrusion experiments, molecular dynamics simulations, and stochastic models to reveal that water intrusion into ZIF-8 occurs by a cascade filling of connected cages rather than a condensation process as previously assumed. The reported results allowed us to establish structure/function relations in this prototypical microporous material, representing an important step to devise design rules to synthesize porous media.

TEPA-SiO2@PDA composite as a highly stable underwater oleophobic coating on copper mesh for oil-water separation with high flux

Specially wettable mesh can effectively separate the oil-water mixture. However, the pore blocking and poor stability limit the application. In this work, a tetraethylenepentamine-silica@polydopamine (TEPA-SiO2@PDA) coating is developed on the copper mesh for oil-water separation. By exploiting the rough structure and hydrophilic molecule, an underwater oleophobic surface is obtained, in which the aforementioned challenges can be addressed. As a result, the TEPA-SiO2@PDA modified mesh presents a high underwater oil contact angle and stability at various pH and temperature. Oil-water separation test confirms the high efficiency (>99 %) and high water flux. After 15 cycles of separation testing, it still exhibits a high efficiency of 98.21 % and water flux of 23,315.2 L m−2 h−1. High intrusion pressure and special rough structure contribute to the good oil-water separation ability and high stability. This work proposed a novel strategy for designing a highly stable underwater oleophobic mesh for oil-water separation.

ZnO/WO3.H2O micro-nanostructures coated mesh for efficient separation of oil-water mixture

In this work, we report the fabrication of superhydrophilic-underwater superoleophobic ZnO/WO3.H2O coated stainless steel mesh for the effective oil-water separation. X-ray diffraction studies confirm the occurrence of hexagonal wurtzite and orthorhombic phase of ZnO and WO3.H2O respectively in the ZnO/WO3.H2O coated mesh. The superhydrophilic-underwater superoleophobic nature of ZnO/WO3.H2O covered mesh is attributed to the innate hydrophilicity and surface roughness of WO3.H2O, which is again enhanced by the inclusion of ZnO. The oil-water separation efficiency of ZnO/WO3.H2O covered stainless steel mesh was over 98% for various oil-water mixtures. The coated mesh maintains high efficiency of separation even after 10 cycles of operation. Moreover, the as-deposited meshes demonstrated good separation ability for the emulsified oil droplets larger than its pore size. The excellent abrasion-resistant ability of ZnO/WO3.H2O coated mesh indicate its excellent mechanical stability. In addition, the high intrusion pressure of ZnO/WO3.H2O coated mesh favors the separation of oil-water mixture in large volumes. Furthermore, the photocatalytic activity of the coated mesh could degrade the organic pollutants present in the oil-water mixture. The proposed novel strategy in designing a multifunctional surface paves the way for the treatment of oleaginous water for environmental remediation.

Facile Approach to Fabricate a High-Performance Superhydrophobic Mesh.

When superhydrophobic meshes are used for oil/water separation, high flux and high intrusion pressure are usually compromised. Herein, a high-performance superhydrophobic stainless steel mesh membrane with a hairy-like poly(divinylbenzene) (PDVB) coating is fabricated by precipitated cationic polymerization. The synthesis is facile, which is completed in one step at ambient temperature within a short time, i.e., less than 90 s. The unique hair-like microstructure of PDVB is responsible for the superhydrophobic performance with less blockage for the pores. A higher flux for oil is achieved while keeping a high intrusion pressure. Especially, the ellipsoidal pore texture with two sharp tips can give additional high intrusion pressure. In the case of 2800 mesh, the superhydrophobic mesh displays an unprecedentedly high value of up to 22 kPa while maintaining a high flux of 2.0 × 104 L·m-2·h-1. The high intrusion pressure enables further increment of flux to 4.2 × 104 L·m-2·h-1 under a reduced pressure at a higher loading. The current high-performance superhydrophobic mesh realizes higher efficiency in separating oil/water mixtures, which is promising for practical applications, for example, in industrial extraction.

Research on the Characteristics of Microscopic Damage to Different Pore Types by Slippery Water Fracturing Fluid in the Chang Member Tight Sandstone Reservoir, Ordos Basin, NW China

This paper examines the damage caused by slickwater fracturing fluid to the microscopic pore structure of tight sandstone in the Chang 7 member in the Ordos Basin. A submicron CT in situ displacement system was used to analyze and graphically represent changes in pores in core samples following fracturing fluid damage. The results show the following: (1) the damage caused by slickwater fracturing fluid to tight sandstone fractures mainly occurs in the early stage of fluid incursion. The damage is characterized by a decrease in the effective pore volume, increase in the number of pores, and insignificant subsequent damage. The main causes of pore damage by slickwater fracturing fluid are retention of slickwater in the liquid phase and hydration swelling of clay minerals in the pores. (2) After the high pressure intrusion of slickwater fluid, the pore size of large-size intergranular pores increases, and there is no obvious damage after water flooding. However, fractures and small dissolution pores in the cores are the main areas of fluid retention after fracturing fluid invasion due to their small flowing radius and complex structure. These are the locations where damage mostly occurs.

Thermal state of the upper mantle and the origin of the Cambrian-Ordovician ophiolite pulse: Constraints from ultramafic dikes of the Hayachine-Miyamori ophiolite

Abstract Ophiolite pulses, which are periods of enhanced ophiolite generation and emplacement, are thought to have a relevance to highly active superplumes (superplume model). However, the Cambrian-Ordovician pulse has two critical geological features that cannot be explained by such a superplume model: predominance of subduction-related ophiolites and scarcity of plume-related magma activities. We addressed this issue by estimating the mechanism and condition of magma generation, including mantle potential temperature (MPT), from a ~500 Ma subduction-related ophiolite, the Hayachine-Miyamori ophiolite. We developed a novel method to overcome difficulties in global MPT estimation from an arc environment by using porphyritic ultramafic dikes showing flow differentiation, which have records of the chemical composition of the primitive magma, including its water content, because of their high pressure (~0.6 GPa) intrusion and rapid solidification. The solidus conditions for the primary magmas are estimated to be ~1450 °C, ~5.3 GPa. Geochemical data of the dikes show passive upwelling of a depleted mantle source in the garnet stability field without a strong influence of slab-derived fluids. These results, combined with the extensive fluxed melting of the mantle wedge prior to the dike formation, indicate sudden changes of the melting environment, its mechanism, and the mantle source from extensive fluxed melting of the mantle wedge to decompressional melting of the sub-slab mantle, which has been most plausibly triggered by a slab breakoff. The estimated MPT of the sub-slab mantle is ~1350 °C, which is very close to that of the current upper mantle and may reflect the global value of the upper mantle at ~500 Ma if small-scale convection maintained the shallow sub-slab mantle at a steady thermal state. We, therefore, conclude that the Cambrian-Ordovician ophiolite pulse is not attributable to the high temperature of the upper mantle. Frequent occurrence of slab breakoff, which is suggested by our geochemical compilation of Cambrian-Ordovician ophiolites, and subduction termination, which is probably related to the assembly of the Gondwana supercontinent, may be responsible for the ophiolite pulse.

Energetic Performance of Pure Silica Zeolites under High-Pressure Intrusion of LiCl Aqueous Solutions: An Overview.

An overview of all the studies on high-pressure intrusion—extrusion of LiCl aqueous solutions in hydrophobic pure silica zeolites (zeosils) for absorption and storage of mechanical energy is presented. Operational principles of heterogeneous lyophobic systems and their possible applications in the domains of mechanical energy storage, absorption, and generation are described. The intrusion of LiCl aqueous solutions instead of water allows to considerably increase energetic performance of zeosil-based systems by a strong rise of intrusion pressure. The intrusion pressure increases with the salt concentration and depends considerably on zeosil framework. In the case of channel-type zeosils, it rises with the decrease of pore opening diameter, whereas for cage-type ones, no clear trend is observed. A relative increase of intrusion pressure in comparison with water is particularly strong for the zeosils with narrow pore openings. The use of highly concentrated LiCl aqueous solutions instead of water can lead to a change of system behavior. This effect seems to be related to a lower formation of silanol defects under intrusion of solvated ions and a weaker interaction of the ions with silanol groups of zeosil framework. The influence of zeosil nanostructure on LiCl aqueous solutions intrusion–extrusion is also discussed.

The effect of nanostructures on high pressure intrusion–extrusion of water and electrolyte solutions in hierarchical nanoboxes of silicalite-1

A drastic effect of the presence of cavities on high pressure intrusion–extrusion of LiCl aqueous solution in silicalite-1 nanoboxes is observed.

Fabrication of superhydrophobic marigold shape LDH films on stainless steel meshes via in-situ growth for enhanced anti-corrosion and high efficiency oil-water separation

A superhydrophobic marigold shape layered double hydroxide (LDH) film coated stainless steel mesh (SSM) was prepared by in-situ growth followed chemical modification in this work. The obtained SSM exhibited excellent superhydrophobicity, self-cleaning ability, physical and chemical durability, indicating the superior ability of adapting to outdoor environment. In addition, the obtained SSM also exhibited excellent corrosion resistance and the efficiency reached up to 97.3%. As for application evaluation, the obtained SSM could be applied in continuous oil-water separation with a high efficiency and flux after 50 times reuse (98.5% and 1800 L m−2 h−1 for chloroform-water mixture). More importantly, the obtained SSM exhibited a high intrusion pressure (5.39 kPa), which was helpful to the rapid separation of oil-water mixture. Consequently, the obtained superhydrophobic SSM offered a promise in solving practical application problems of oil-water separation in outdoor and thereby showed great potential in large-scale industrial applications.

Swelling Poly(ionic liquid) Supported by Three-Dimensional Wire Mesh for Oil/Water Separation.

A kind of oil/water separation membrane, combining poly(ionic liquid) (PIL) and three-dimensional (3D) wire mesh, was designed and prepared via one-step photopolymerization of an ionic liquid monomer 1,8-triethylene glycoldiyl-3,3'-divinylimidazolium dibromide ([DVIm-(EG)3]Br2) with acrylic acid in the mesh. The composite membrane (PIL@Mesh) had the advantages of anti-oil-adhesion property and high mechanical strength simultaneously. The morphology of PIL@Mesh characterized by scanning electron microscopy (SEM) and Cryo-SEM demonstrated that PIL swelled in water to construct microscale 3D networks. The 3D networks of swelling PIL were capable of forming a hydration layer and endowed PIL@Mesh with superhydrophilicity, which made the membrane to transport water but to intercept oil. PIL@Mesh showed excellent separation efficiency (above 99.9%) for various oil/water mixtures, large water flux (47 L·m-2·s-1), and high intrusion pressure (1.2 kPa). Meanwhile, it performed well in recyclability and corrosion-resistant under harsh conditions, such as acid, alkaline, and salty environments.

High pressure intrusion of water and LiCl aqueous solutions in hydrophobic KIT-6 mesoporous silica: Influence of the grafted group nature

Abstract High pressure intrusion-extrusion of water and LiCl aqueous solutions in KIT-6 mesoporous silica grafted with alkyl or perfluoroalkyl groups have been studied for absorption of mechanical energy. The “grafted KIT-6 – LiCl solution” systems demonstrate a shock absorber behavior with a large hysteresis between intrusion and extrusion curves and partially irreversible intrusion in the first intrusion-extrusion cycle. The samples of KIT-6 with perfluroalkyl grafting demonstrate higher values of intrusion pressure in comparison with ones grafted with alkyl groups, but lower intruded volume. It has been found that the intrusion of LiCl solutions leads to a considerable increase of intrusion pressure, particularly pronounced in the case of the samples grafted with perfluoroalkyl groups. This increase is higher than one expected from the Laplace-Washburn equation. When salt concentration increases, the intrusion becomes more reversible in the case of alkyl grafting, but slightly less in the case of perfluoroalkyl one.

Phase Transformations of Metal–Organic Frameworks MAF-6 and ZIF-71 during Intrusion–Extrusion Experiments

In this work, the energetic behaviors of two zeolitic imidazolate framework (ZIF) materials, ZIF-71 and the highly porous MAF-6, of RHO topology are studied in high-pressure intrusion–extrusion exp...

Numerical study of asymmetric vertical fluid intrusion in deep reservoirs: Effects of stress, temperature and salinity

Non-symmetric upward and downward pressure diffusion from the point of intrusion is a common phenomenon in fluid-triggered seismicity. In most studies, a stress and pressure dependent permeability is applied resulting in a depth-dependency. An alternative source of non-symmetric diffusion are variations in fluid properties with depth due to temperature or salinity gradients causing buoyancy and affecting hydraulic diffusivity. We evaluate these processes to identify to what extent each may result in non-symmetric diffusion. We find that over short time scales of a couple days, stress-dependent permeability has the strongest influence on non-symmetric diffusion processes, while temperature effects become more important over longer time scales of months. Salinity plays only a very minor role. We verify these findings by applying our model to the 2008 West-Bohemian swarm, which is most likely triggered by degassing CO2 from the mantle. As the first swarm phase lasts thirty days with high pressure intrusion for approximately 7 days, we verify that asymmetric diffusion is dominated by the mechanical and hydraulic state of the system. Although density and viscosity of supercritical CO2 vary strongly in the pressure and temperature range present, due to the small amount of intruding fluid, the temperature and buoyancy effect is limited. Hence, we require unrealistic permeability gradients with depth to explain the asymmetric vertical pressure diffusion observed. We introduce an increased permeability based on fracture (re-)activation as contributor to intensify asymmetric diffusion and reducing the necessity of exaggerated permeability gradients. We conclude, that for short-term events up to 50 days simulations of realistic seismic cloud behavior will require constraints with respect to depth-variations of the hydraulic parameters and should consider increased permeability due to fracture (re-)activation. Long-term simulations over months require a sophisticated coupling of heat and fluid flow in combination with an adequate equation of state for the fluid phase.

Nanopore characterization of mine roof shales by SANS, nitrogen adsorption, and mercury intrusion: Impact on water adsorption/retention behavior

Moisture-induced reduction in the strength of shales is one of the primary mechanisms of roof degradation affecting the stability and safety of underground coal mines. The underlying mechanisms of nanoscale matrix-water interactions remains unclear. Thus, an improved understanding of the nanopore structure, and dependent water adsorption and retention behavior of shale is key in defining strength degradation due to seasonal variations in humidity and temperature in underground coal mines. We use small-angle neutron scattering (SANS), low-pressure N2 adsorption (LPNA), and high-pressure mercury intrusion porosimetry (MIP) to characterize the nanopore structure of a fireclay (7F) and four coal mine roof shales (6R, 5A, 6F, H6) from the Illinois basin. The results show that overall distributions of pore volume obtained from SANS, LPNA and MIP techniques agree well between methods and over a wide range of pore size from ~1 nm to ~100 nm. Mercury porosities for the five ordered (7F, 6R, 5A, 6F, H6) samples (7.3%, 7.8%, 8.3%, 12.3%, 4.6%) are higher than the respective N2 porosities (5.0%, 6.3%, 3.8%, 8.2%, 2.5%), as attributed to the dilation of mesopores and compression of the grain skeleton induced by high pressure intrusion of mercury. The SANS porosities for samples 7F, 6R, 5A, 6F (4.0%, 6.2%, 4.1%, 8.8%) are in good agreement with their N2 porosities. Among all tested samples, H6 shale exhibits a relatively high SANS porosity (8.0%) but the lowest N2 (2.5%) and mercury porosities (4.6%). This is attributed to the interlayer micro-pore spaces within montmorillonite, which is detected by SANS but not by the two fluid penetration methods due to the inaccessibility of N2 molecules and mercury. Based on LPNA, larger micropores (1.5–2 nm) and mesopores (2–50 nm) predominantly contribute to the total porosity (~77.8%–87.6%) for the five tested samples.The water adsorption isotherms are measured by dynamic vapor sorption (DVS) and water retention curves are calculated based on the characterized pore size distribution (PSD) by LPNA and MIP techniques. Pore structures of the five studied samples evidently exert a strong influence on their water adsorption and retention behaviors. Water adsorption capacity correlates positively with total porosity/specific surface area (SSA), with a large proportion of micro/meso-pores resulting in the strong water retention capacity with matric suction reaching ~100–150 MPa for liquid saturation < 3%. Among the studied fireclay/shales, samples with higher retention capacity tend to adsorb more water. Thus, nanopore structure and its impact on water adsorption and retention behavior exert the key controls on shale-water interaction and its implication on strength reduction of roof shales in underground coal mines.

Liquid Intrusion into Zeolitic Imidazolate Framework-7 Nanocrystals: Exposing the Roles of Phase Transition and Gate Opening to Enable Energy Absorption Applications

Liquid intrusion into zeolitic imidazolate framework 7 (ZIF-7) has been observed for the first time. Among the three typical phases of ZIF-7, we discover that only the guest-free ZIF-7-II structure can be intruded by mechanical pressure, and intriguingly, this pressurized liquid intrusion behavior is detected only in nanocrystals, indicating the crystal size effect. Because of its unique combination of non-outflow property and high intrusion pressure, water intrusion into ZIF-7-II generates a marked energy dissipation capacity of ∼2 J/g despite its limited pore volume. We present several strategies that can be easily implemented to tune its intrusion pressure and energy dissipation and accomplish material reusability. Remarkably, we found that the pore cavities of ZIF-7-II can accommodate water molecules without experiencing any phase transition, which is entirely different from other solvents whose incorporation will trigger a spontaneous conversion into ZIF-7-I. Our pressure-vs-volume data further reveal that the process of water infiltration and retainment is controlled by the gate-opening/closing mechanism, which has enabled us to probe the viscoelasticity of ZIF-7 via cyclic liquid intrusion experiments. This study has deepened our understanding of the time-dependent mechanical properties of ZIFs and shed new light on the structural flexibility central to the novel applications of metal-organic framework materials.

A pair of MnO2 nanocrystal coatings with inverse wettability on metal meshes for efficient oil/water separation

Water contamination arising oil spill and industrial oily wastewater discharge has posed a severe threat to ecological environment and human health. To address the issues, the metal meshes with superwetting performance for selective oil/water separation have received extensive attention. But, it is still a great challenge to fabricate durable meshes with special wettability and high liquid intrusion pressure, which can be utilized for oil/water separation under harsh environments. Herein, two types of MnO2 nanocrystal coated meshes with inverse wettability, namely superhydrophobicity and underwater superoleophobicity, were fabricated via a single hydrothermal strategy or combining dipping modification. The resulting superhydrophobic mesh and underwater superoleophobic mesh are suitable for removing heavy oil and light oil from water, respectively. The oil/water separation efficiencies of greater than 96.2% are achieved for the two meshes. Importantly, both meshes exhibit quick separation rate for the permeable liquid and high intrusion pressure (>1.38 kPa) for the intercepted liquid, and can maintain excellent superwetting performance and high oil/water separation efficiency under harsh environments (acidic, alkakine and high-concentration salt solutions). We believe the as-fabricated meshes are promising and effective filters for purifying oil-polluted water.

Energetic Performances of Pure-Silica DDR Zeolite by High-Pressure Intrusion–Extrusion of Electrolyte Aqueous Solutions: A Shock-Absorber with Huge Absorbed Energy

Pure-silica DDR-type zeolite (zeosil) displays a porosity composed of two kinds of small cages (pore opening of 4–6 MR) and of a large nonadecahedron cage with pore windows of 8 MR. In order to study the energetic performances of this hydrophobic material by high-pressure intrusion–extrusion experiments, water and 10 and 20 M LiCl aqueous solutions were chosen as nonwetting liquids. The intrusion pressure increases from 60 to 357 MPa when using water and 20 M LiCl aqueous solution, respectively. The latter pressure is the highest ever found for a zeosil-based system. It is associated with a large intruded volume of 0.26 mL/g, which is close to the total theoretical porosity of the DDR structure. The corresponding “DDR-20 M LiCl aqueous solution” system demonstrates mainly shock-absorber behavior, and both features (high intrusion pressure and large intruded volume) lead to the highest amount of absorbed mechanical energy for such systems: 93 and 61 J/g for the first and the following intrusion cycles, res...