Macropore Walls Research Articles

Study on the microscopic percolation mechanism of different aqueous media huff‐n‐puff with cores in Fengxi tight oil reservoirs of Qinghai Oilfield

AbstractHuff‐n‐puff (HnF) is a crucial technology for effectively enhancing the oil recovery (EOR) of tight oil reservoirs. Soaking period is the primary platform for injection medium interacting with formation fluid and reservoir rock in HnF. Elucidating the micro‐percolation mechanism of the soaking period is immensely significant for guiding oilfield production practices. The present study established a physical simulation method combining HnF experiments with nuclear magnetic resonance to reveal the microscopic percolation mechanisms, including water, fracturing fluid, and surfactant. Furthermore, the impacts of soaking time, HnF cycles, wettability, and pore structure on oil recovery degree were quantified. The results demonstrate the crucial significance of wettability and pore structure in the soaking period. The dominant mechanism during water HnF in reservoirs characterized by well‐connected pore networks and minimal clay pores is micropore imbibition, while conversely, macropore displacement plays a predominant role. The oil recovery degree of fracturing fluid HnF primarily relies on mitigating solid‐fluid forces within macropores. The surfactant HnF in preferential water‐ and oil‐wet reservoirs is primarily governed by oil films stripped from macropore walls and micropore imbibition, respectively. Specifically, water and fracturing fluid HnF are suitable for shorter soaking time and fewer HnF cycles, whereas the surfactant HnF exhibits an inverse relationship.

Hierarchical Incorporation of Reduced Graphene Oxide into Anisotropic Cellulose Nanofiber Foams Improves Their Thermal Insulation.

Anisotropic cellulose nanofiber (CNF) foams represent the state-of-the-art in renewable insulation. These foams consist of large (diameter >10 μm) uniaxially aligned macropores with mesoporous pore-walls and aligned CNF. The foams show anisotropic thermal conduction, where heat transports more efficiently in the axial direction (along the aligned CNF and macropores) than in the radial direction (perpendicular to the aligned CNF and macropores). Here we explore the impact on axial and radial thermal conductivity upon depositing a thin film of reduced graphene oxide (rGO) on the macropore walls in anisotropic CNF foams. To obtain rGO films on the foam walls we developed liquid-phase self-assembly to deposit rGO in a layer-by-layer fashion. Using electron and ion microscopy, we thoroughly characterized the resulting rGO-CNF foams and confirmed the successful deposition of rGO. These hierarchical rGO-CNF foams show lower radial thermal conductivity (λr) across a wide range of relative humidity compared to CNF control foams. Our work therefore demonstrates a potential method for improved thermal insulation in anisotropic CNF foams and introduces versatile self-assembly for postmodification of such foams.

Geometrically effective NiAl2O4 formation over macroporous Ni/Al2O3 catalysts and coking resistance in dry reforming of methane

This study aimed to investigate the geometrical effect of macroporosity on the performance of Ni-based catalysts in the dry reforming of methane (DRM). For this, macroporous Ni/Al2O3 catalysts with different Ni contents were synthesized. Characterization experiments on the macroporous Ni/Al2O3 catalysts revealed that the macroporous Al2O3 structure enhanced NiAl2O4 formation by facilitating efficient interactions between the Ni species and accessible Al2O3 sites on the macroporous wall surface during calcination. In a subsequent reduction step, Ni exsolution from the NiAl2O4 structure generated highly dispersed Ni nanoclusters over the macroporous Al2O3. Conversely, non-macroporous Ni/Al2O3 catalysts presented substantial amounts of large isolated Ni nanoparticles at an Ni content of 20 wt%, owing to limited NiAl2O4 formation caused by the lack of accessible Al2O3 sites. The highly dispersed Ni nanoclusters surrounded by oxygen vacancies on the macroporous Ni/Al2O3 catalysts significantly enhanced their catalytic performance in the DRM, evidenced by their high CO2 and CH4 conversions and strong resistance to coking. Moreover, the superior coke resistance ability of the macroporous Ni/Al2O3 catalysts was attributed to the gasification of the coke precursor on Ni nanoclusters surrounded by oxygen vacancies during the DRM.

Enhanced visible‐light‐driven photocatalytic application for water purification and hydrogen evolution by large‐sized nanofilm‐constructed hierarchical porous g‐C3N4/SiO2

AbstractThe large‐sized nanofilm‐constructed hierarchical porous SiO2 (LNCHPS) is successfully prepared by the dual templating approach and subsequently used as the support for g‐C3N4. A series of characterization techniques are conducted to evaluate the structure and property of the as‐prepared materials. The LNCHPS possesses two sets of explicated successive pass‐through macropores (0.5–1.0 µm) with large specific surface area. In addition, the macropore wall is constructed by uniform mesoporous nanofilms with the thickness ranging from 35 to 50 nm. Then, the photocatalytic property is investigated by degradations towards Rhodamine B (RhB) under simulated sunlight, in which experiments have been performed through controlling the g‐C3N4 loading contents, solution pH values, and photocatalyst dosages. The apparent rate constant of g‐C3N4/LNCHPS could reach 0.03 min−1 under optimum conditions, showing 6.0 times that of the bulk g‐C3N4. In addition, g‐C3N4/LNCHPS also exhibits significantly enhanced performance in H2 evolution (39.9 µmol h−1) compared to that of the bulk g‐C3N4. High light absorption and utilization, enhanced adsorption capability and quick electron hole separation can render this fine structure excellent photocatalytic performance. Our work enables a facile route for large‐scale preparation of g‐C3N4/LNCHPS for addressing the wastewater treatment and hydrogen energy production simultaneously.

Interactions of macropores with tides, evaporation and rainfall and their effects on pore-water salinity in salt marshes

Salt marshes, a type of coastal wetlands, are influenced by various hydrogeological processes. These processes affect water and salt transport and play a critical role in determining the ecosystem services of salt marshes. Responses of pore-water flow and soil moisture to individual factors (e.g., macropores, evaporation and semidiurnal tides) have been well examined. However, how macropores interact with spring-neap tides, evaporation and rainfall and affect pore-water salinity in salt marshes remains unclear. This study investigated this question by analyzing water exchange across the marsh surface and the distribution of pore-water salinity in marsh sediment, based on a three-dimensional marsh-creek model. The results reveal high spatial heterogeneity of pore-water salinity in the presence of macropores. Due to the lateral recharge of macropore water, a negative salinity gradient is formed from macropore walls toward adjacent sediment. Additionally, macropores’ impact on water exchange and salt transport varies with distance from creeks. This results in two mechanisms by which macropores affect pore-water salinity, flushing and recharging. In well-drained near-creek areas, macropores reduce salt accumulation (flushing) compared with salt marshes without macropores. Whereas in the poorly-drained marsh interior, the recharge from macropores inhibits rainfall infiltration. This, together with enhanced evaporation, increases pore-water salinity (recharging) in the shallow soil layer. Moreover, the macropores’ impacts on pore-water salinity vary remarkably with macropore density. This study improves the understanding of pore-water salinity distribution in coastal wetlands and has potential implications for related biogeochemical processes.

Facile Preparation of Petroleum Pitch-Based Activated Carbon with Open Macropore Walls for High Energy Density Supercapacitors

Electric double-layer capacitors have attracted considerable attention for energy storage because of their excellent power capability, high stability, and long cycle life. Activated carbon is the most widely employed electrode material for electric double-layer capacitors owing to its high specific surface area, hierarchical porous structure, and high electrical conductivity. However, to increase the energy density of the devices, new synthetic methods for enhancing their specific capacitances are required. We developed a facile preparation method for petroleum pitch-based activated carbon and investigated the optimal conditions to improve its electrochemical performance in terms of rate capability, specific capacitance, and cycle life. The obtained activated carbon exhibited a high specific capacitance (163.67 F/g at 0.1 A/g), which can be attributed to the efficient charge transport due to the micropores developed in the open macroporous walls of the carbon structure and the high electrical conductivity. Our approach provides an efficient strategy for synthesizing activated carbon with excellent properties. The results reveal a correlation between the physicochemical and electrochemical properties of activated carbon.

Macroporous TiO2 and Graphite-like Carbon Hybrid Hierarchical Interfaces for Improved Photocatalytic Activity Derived from Particle-Stabilized Emulsions

Hierarchical macroporous TiO2/graphite-like carbon hybrid photocatalyts were successfully prepared by a facile method employing a particle-stabilized high internal phase emulsion (Pickering emulsion) as the template and sucrose as the carbon source. The results of this study showed that mesopores, with diameters ranging from 10 to 50 nm, were homogeneously distributed on the cell-window structured macropore walls that were armored by nano-sized TiO2 particles. Moreover, a microporous graphitic layer of thickness ∼2 nm surrounded the surface of the TiO2 particles. This type of hierarchical macro-meso-microporous structure with high-efficiency diffusion and mass transfer properties, along with the porous graphitic layers with a high BET surface area, resulted in a hybrid catalyst possessing high adsorption rate and capacity. In addition, the carbon layers suppressed the transition temperature of titania (anatase to rutile) by more than 200 °C. The green method presented here can potentially be employed for the preparation of cost-effective environmental materials toward the degradation of dyes and other pollutants.

Hierarchically Periodic Macroporous CdS–ZnO Heterojunctions with Multiple Quantum Well-like Band Alignments for Efficient Photocatalytic Hydrogen Evolution without a Cocatalyst

Heterostructures constructed by conventional methods, particularly those randomly distributed manner on the catalyst surface as well as forming core–shell structures, lead to imbalance in carrier utilization, limitation of charge extraction/transfer, and hindrance of light harvesting. In this study, we constructed a new type of heterostructure consisting of alternate CdS and ZnO grains bridged with good interfaces in the hierarchically periodic macroporous (HPM) walls by the pyrolysis of CdZnS solid solution in a polymethyl methacrylate nanoreactor. Since the alternately arranged CdS–ZnO heterojunctions in the HPM form multiple quantum well-like (MQW-like) band alignments that favor the Z-scheme charge transfer, the photogenerated electrons and holes are spatially separate and accumulated on CdS and ZnO parts, respectively. Besides the desirable spatial separation of the photogenerated charges, the enabled excellent mass transfer in the macroporous structures effectively accelerates the utilization of the carriers. Owing to the synergistic effect of the MQW-like band alignments and the HPM structures, the photocatalytic H2 evolution rate of HPM CdS–ZnO is as high as 587.8 μmol h–1 without a cocatalyst. This work introduces a fascinating strategy for the creation of alternate heterojunctions to improve carrier utilization.

Криогенно-структурированный миметик внеклеточного матрикса на основе концентрированного коллагенсодержащего раствора

Viscoelastic hydrogels based on animal tissue extracts are considered promising biomimetics of the extracellular matrix (ECM) due to their proven effectiveness for stimulating the regeneration of the liver, pancreas and articular cartilage. Cryostructuring is an approach that makes it possible to give polymer scaffolds macroporosity and provide mechanical strength. preparation of a new macroporous cryogenically structured biomimetic of ECM based on a commercially available concentrated collagen-containing solution and evaluation of the possibilities of its application in tissue engineering. The target spongy collagen-containing material was obtained by sequential freezing of a concentrated collagen-containing solution, its subsequent lyophilization and chemical tanning by treatment with an alcohol solution of carbodiimide. The morphology of the cryostructured multicomponent collagen-containing material was studied using optical and scanning electron microscopy (SEM) using lanthanide contrast. The cytotoxicity of the scaffold was studied on the culture of human adipose-derived stem cells (hADSCs). Adhesion and proliferation of hADSCs on the scaffold surface were studied on the 7th day of cultivation. The compression modulus of elasticity of the obtained collagen–containing material in the swollen state in water was 35,3 ± 2,2 kPa, the total water-holding capacity of the material was 45.80 ± 0.46 ml/g of polymer, and the degree of swelling of the walls of macropores was 3.99 ± 0.31 ml/g. During SEM examination and histological staining with hematoxylin and eosin, a broad-pored structure was observed on the surface and cross-section of the disc. The pores in the upper part are larger (the average diameter is not less than ~ 30 µm) than the pores in the lower part of the sponge (the average diameter is not more than ~ 30 µm) due to the occurrence of a vertical temperature gradient. The matrix did not have cytotoxicity relative to the hADSCs. In the sample, active proliferation of hADSCs was observed on the surface of the scaffold. It was shown that the developed cryostructurates based on a concentrated collagen-containing solution had supermacroporosity and a compression modulus of elasticity of 35.3 ± 2.2 kPa. The absence of cytotoxicity and the ability to maintain adhesion and proliferation of hADSCs indicate the possibility of using cryogenically structured biomimetic of the extracellular matrix in tissue engineering and regenerative medicine.

A facile strategy toward hierarchically porous composite scaffold for osteosarcoma ablation and massive bone defect repair

The surgical treatment of osteosarcoma remains a challenge because of massive bone defects and tumor recurrence. Herein, a facile strategy inspired by cooking is developed to fabricate hierarchically porous composite scaffold for bone tumor ablation and massive bone defect repair. Silk fibroin (SF) as a biological foaming agent is foamed by mechanical stirring to form physical hydrogel through strong interaction with 2D Ti 3 C 2 MXene nanosheets . Bacterial cellulose (BC) is used to stabilize air bubbles to keep porous structure . Hierarchically porous SF/BC/MXene (FSCM) scaffold with ∼200 μm macropore and nanofibrillar wall is acquired by lyophilization. Such FSCM composite scaffold presents prominent osteosarcoma ablation performance after near-infrared (NIR) light irradiation, and features excellent bone defect repair ability. This work represents a newly strategy to fabricate hierarchically porous bifunctional scaffold for enhancing bone tumor ablation and facilitating massive bone defect repair in the clinical treatment of osteosarcoma. • Protein foaming is a valid strategy for fabricating multifunctional bone tissue engineering composite scaffold. • MXene endowed FSCM scaffold with excellent osteosarcoma ablation performance. • Hierarchically porous bio-mass scaffold presented prominent bone defect repair capability. • Multifunctional bio-mass composite scaffold showed great prospect for the clinical treatment of osteosarcoma.

Macropores in a compacted soil impact maize growth at the seedling stage: Effects of pore diameter and density

Macropores are often regarded as preferential paths for root growth to bypass high-strength soil. However, the influence of macropore characteristics on root growth in compacted soils is not clearly understood. In this study, we investigated the effects of macropore diameter, density, wall surface area and porosity in a compacted soil on maize growth and N uptake at the seedling stage. Different diameters (0.5-, 1- and 2-mm) and densities (0, 1750, 3500, 7000 and 28,000 m−2 indicated by 0, 5, 10, 20, 80 numbers, respectively) of artificial macropores were created in compacted (1.6 g cm−3) soil columns (150 mm height × 60 mm internal diameter). The absence of macropores was treated as a Control. After 20 days of maize growth, the 3D root architecture and the interaction between roots and macropores were visualized and quantified using X-ray computed tomography (CT). The nitrogen uptake by plants from the compacted subsoil was determined using 15N tracer. Our results showed that the presence of 0.5- or 1-mm macropores enhanced maize growth and 15N uptake relative to the Control, but not the presence of 2-mm macropores. At a given macropore diameter of 0.5-mm, the effect of macropore density on maize growth and 15N uptake was in the order of 7000 m−2 > 28,000 m−2 and 1750 m−2. Under the same macropore wall surface area conditions (i.e., 2513 mm2 in this study), maize growth and 15N uptake decreased with increasing macropore diameter. Under the same macroporosity (i.e., 0.342% in this study), maize growth and 15N uptake were more promoted by macropore characteristics of 1-mm diameter with 7000 m−2 density and 0.5-mm diameter with 28,000 m−2 density compared with 2-mm diameter with 1750 m−2 density. CT images showed that the number of macropores colonized by roots and the intersecting area between roots and macropores both increased with increasing macropore density. Our results demonstrate that the presence of macropores can improve crop growth, but its effect depends on macropore characteristics created by appropriate macropore diameter and density (e.g., 0.5 mm diameter and 7000 m−2 density in this study).

Alkali/alkaline-earth metal-modified MnOx supported on three-dimensionally ordered macroporous–mesoporous TixSi1-xO2 catalysts: Preparation and catalytic performance for soot combustion

The performance of catalysts used in after-treatment systems is the key factor for the removal of diesel soot, which is an important component of atmospheric fine particle emissions. Herein, three-dimensionally ordered macroporous–mesoporous TixSi1-xO2 (3DOM-m TixSi1-xO2) and its supported MnOx catalysts doped with different alkali/alkaline-earth metals (AMnOx/3DOM-m Ti0.7Si0.3O2 (A: Li, Na, K, Ru, Cs, Mg, Ca, Sr, Ba)) were prepared by mesoporous template (P123)-assisted colloidal crystal template (CCT) and incipient wetness impregnation methods, respectively. Physicochemical characterizations of the catalysts were performed using scanning electron microscopy, X-ray diffraction, N2 adsorption–desorption, H2 temperature-programmed reduction, O2 temperature-programmed desorption, NO temperature-programmed oxidation, and Raman spectroscopy techniques; then, we evaluated their catalytic performances for the removal of diesel soot particles. The results show that the 3DOM-m Ti0.7Si0.3O2 supports exhibited a well-defined 3DOM-m nanostructure, and AMnOx nanoparticles with 10–50 nm were evenly dispersed on the inner walls of the uniform macropores. In addition, the as-prepared catalysts exhibited good catalytic performance for soot combustion. Among the prepared catalysts, CsMnOx/3DOM-m Ti0.7Si0.3O2 had the highest catalytic activity for soot combustion, with T10, T50, and T90 (the temperatures corresponding to soot conversion rates of 10%, 50%, and 90%) values of 285, 355, and 393°C, respectively. The high catalytic activity of the CsMnOx/3DOM-m Ti0.7Si0.3O2 catalysts was attributed to their excellent low-temperature reducibility and homogeneous macroporous–mesoporous structure, as well as to the synergistic effects between Cs and Mn species and between CsMnOx and the Ti0.7Si0.3O2 support.

Design of hierarchical porous carbon with three-dimensional network through solvent-free nanocasting method for CO2 capture

A kind of hierarchical porous carbon (HCN) with three-dimensional network frameworks was successfully prepared by solvent-free nanocasting method using glucose as carbon source and ordered MCM-41 type of mesoporous silica with the different particle sizes as template. Meanwhile, its structure features and texture parameters were characterized by using XRD, N2 adsorption-desorption isotherms, SEM and TEM, FT-IR, Raman spectrum, XPS techniques. These results demonstrated that during the process of pyrolysis glucose was strongly interacted with mesoporous silica, leading to effective loading, then inverse duplicated the structure of mesoporous silica. The obtained sequence of hierarchical porous carbons possessed well-interconnected network structure and tunable wall thickness and size of network macropore. As demonstrations, the capacity of absorbed CO2 for serials of hierarchical porous carbons with three-dimensional network frameworks under room temperature was investigated. The result of CO2 adsorption isotherms indicated that the HCN pore architecture and morphologies played a key role in the CO2 capture process, specifically the size of network macropore and thickness of macroporous wall significantly affected the textural structure, the high microporous contents were benefit with improving the capacity of absorbed CO2.

Thin TiO2 Nanocoating of Porous Titanium through Radio Frequency Magnetron Sputtering to Improve the Biological Response of Orthopedic Implants

: The present study applied a TiO2 nanocoating on a titanium foam substrate produced by powder metallurgy through magnetron sputtering. Scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffraction (XRD) were employed to investigate the surface morphologies of the porous specimens and pre- and post-coating phases, respectively. Also, the growth and proliferation of MG-63 cells (osteoblasts) and their attachment and proliferation on the coated porous titanium specimen (relative to the uncoated specimens) were studied using in vitro and methyl thiazol tetrazolium (MTT) cytotoxicity tests. Considering the porous macrostructure of the coated titanium specimen and the nanostructure of the TiO2 coating on the porous surface and macro-pore walls, the coated specimen was found to be effective in the biocompatibility improvement of dental and orthopedic implants.

In Situ Dual-Template Method of Synthesis of Inverse-Opal Co3O4@TiO2 with Wideband Microwave Absorption.

A unique porous TiO2 with Co3O4 nanoparticles anchored in (Co3O4@TiO2) is prepared by a dual-templating method for promoting electromagnetic microwave absorption (EMA). The as-prepared Co3O4@TiO2 possesses a three-dimensional (3D) ordered macroporous TiO2 skeleton and plenty of mesopores, as well as small Co3O4 nanoparticles that coexisted in the macropore walls of the TiO2 skeleton. The introduction of Co3O4 can increase the magnetic loss as well as suppress impedance mismatch, resulting in the regulation of the EMA performance. The synergetic effect of the TiO2 porous framework and Co3O4 nanoparticles with proper ratio promote microwave absorption performance. Therefore, Co3O4@TiO2-2 with 25 wt % Co3O4 nanoparticles content displays a strong and ultrawide effective absorption band (EAB) performance. The Co3O4@TiO2-2 presents a strong reflection loss of -53.9 dB at 2.95 mm. Moreover, it obtains a super broad EAB of ∼12.5 GHz at 5.0 mm. This dual-templating approach for a well-controlled porous structure could be a facial strategy for the development of high-performance electromagnetic wave absorbers.

Coke characteristics and formation mechanism based on the hot tamping coking

Superior quality coke with low CRI (Coke Reactivity Index) and high strength is indispensable for the safe and efficient operation of the blast furnace. The hot tamping coking technology is comprehensively investigated when the coal samples undergo plastic stage to improve the coke quality and save the coking coal resource. The influences of the tamping temperature, holding time and tamping stress on semicoke structures and coke characteristics were examined. Results show that hot tamping operation could effectively enhance the coke quality. When the tamping temperature is low and the holding time is short, lower tamping stress could produce coke with a compact pore structure and low CRI. High stress leads to a significant increase in coke porosity. It weakens the improvement of coke quality because the permeability of semicoke is low and abundant volatile gas is released in the latter coking process. When the tamping temperature and holding time are appropriate, higher stress could obtain high-quality coke with compact pore structure and low CRI due to the higher permeability of semicoke and less volatile gas resided in the semicoke. The crushing strength (SR) is influenced by the CRI, porosity, macropore wall thickness and coke homogeneity. Lower CRI, lower porosity, thicker pore wall and better homogeneity contribute to higher SR.

Experimental study on the effect of three-dimensional porous structures on the vascularization rate of artificial dermis

Experimental study on the effect of three-dimensional porous structures on the vascularization rate of artificial dermis

Preparation of mesoporous nanofilm constructed millimeter-sized macroporous SiO2 for lipase immobilization

A novel mesoporous nanofilm constructed millimeter-sized macroporous SiO 2 (MNCMMS) was prepared through a dual-templating method, using an epoxy resin macroporous polymer with three-dimensional skeleton structure as the shape and macropore structure directing agent and polyethylene glycol 20000 (PEG20000) as the mesopore porogen. MNCMMS was used as the support for immobilization of Pseudomonas fluorescens lipase (PFL) in order to overcome the limitations of the immobilized enzyme on mesoporous nanomaterials and to improve the performance of PFL. The immobilization conditions and the properties of the immobilized PFL were investigated. The structures and properties of the as-prepared materials were investigated by various characterization techniques. The results revealed that MNCMMS possessed two sets of three-dimensional continuous pass-through macroporous channels with uniform pore size (700 nm), large specific surface area (317 m 2 /g) and pore volume (89.2%), high mechanical strength (10.4 MPa), and that the macropore wall was a continuous mesoporous (pore size of 10 nm) nanofilm with the thickness ranging from 40 to 50 nm. Under the optimum conditions, the activity of PFL@MNCMMS reached to 4897 U/g and enzyme activity recovery achieved to 255%. Compared with free lipase, the stability and reusability of the immobilized lipase were significantly improved. Moreover, the immobilized lipase can be easily recovered from the reaction system for reuse. • A novel hierarchically structured porous SiO 2 (MNCMMS) has been prepared. • The activity of PFL immobilized on MNCMMS was significantly enhanced. • PFL@MNCMMS possesses high storage, operational and thermal stabilities. • The macroscopic size of PFL@MNCMMS significantly improves the recyclability.

Nano-encapsulated solvent via pickering emulsion in NaOH aqueous solution for indoor CO2 capture

Considering the limitations of indoor ventilation owing to air pollution, CO2 concentration rises rapidly to 3000 ppm, which is a level that can affect human health. It is essential to develop materials to reduce naturally occurring CO2 in the buildings. Herein, a nano-encapsulated solvent (NES) via Pickering emulsion is proposed for indoor CO2 capture. NaOH aqueous solution is wrapped with hydrophobic surface-functionalized SiO2 (HS-SiO2) nanoparticles, and the corrosiveness of NaOH is not caused by HS-SiO2 wall. CO2 capture capacity of NES-NaOH is evaluated as 7.57 mmol-CO2/g-solvent which is the highest compared to other solvents including metal-organic frameworks (MOFs); it exhibits excellent structural stability in terms of temperature, time, moisture, and CO2 reaction. NES-NaOH presents high selectivity toward CO2 molecules due to the characteristics of NaOH with high gas permeability of macroporous silica wall and it is dispersed in a silicone oil harmless to human body. It is concluded that NES-NaOH can be successfully applied to air purifier filter to control the CO2 concentration in buildings.

Enhanced release rate of the poorly water-soluble ginsenoside Rg3 with ordered meso/macroporous silica

Although ginsenoside Rg3 is very important in pharmaceutical field, the application of this drug is greatly limited by the release rate due to its poor dissolution. Here we introduced a meso/macroporous SiO2 to assist dispersing Rg3. The as-obtained SiO2/Rg3 (m/M-SiO2/Rg3) with this well-designed support showed superior Rg3 release rate compared to a mesoporous SiO2/Rg3 (m-SiO2/Rg3) at the same release duration and Rg3 loading 20 wt%. The excellent performance of the carrier drug could be attributed to the structural characteristics of hierarchically porous SiO2. On one hand, the macropores (~ 270 nm) accommodate for the active ingredient as effective reservoirs, more importantly the interconnected macropores efficiently shortens the paths of transferring Rg3, which facilitates releasing Rg3 at the nearest mesoporous channels (~ 2.8 nm) penetrated on the wall of adjacent macropores.