Continuous Macropores Research Articles

Synthesis of reverse-selective nanoporous ultrafiltration membranes using dual phase separations of ionic liquid and Poly(ethylene glycol) from the gelating urea-linked covalent network

Many membranes with various pore structures have been studied for size-based selective filtration and separation. However, one exhibiting reverse size selectivity has rarely been reported. Here, we present a facile synthesis of a hierarchically nanoporous covalent framework (NCF) membranes using concurrent phase separation and gelation of the mixtures of a urea-linked network (UN) sol, poly (ethylene glycol) (PEG), and ionic liquid (IL). Subsequent solvent extraction of the dual porogens, i.e., PEG and IL, from the ternary blend gave a hierarchically nanoporous structure consisting of a continuous macropore running across a continuous mesoporous framework. The structure formation was accounted for by the primary separation of the IL-rich phase, followed by the secondary separation of the PEG domain from the continuous UN skeleton. The porosity and pore distribution of the membrane was varied by adjusting the composition of the PEG/IL/UN mixture. The hierarchical nanoporosity provided a reverse size selectivity for the ultrafiltration of proteins and polymers, promising potential applications in membrane-based protein purification or chromatography.

Soil gas diffusivity and pore continuity dynamics under different tillage and crop sequences in an irrigated Mediterranean area

Gas diffusion can be used to quantify soil quality and structural development that is strongly affected by soil use and management practices. There is a lack of information about the quantitative effect of tillage combined with crop sequences on soil structure. This study aimed to quantify the effects of tillage and crop sequences on soil bulk density, gas diffusivity, air-filled porosity, and the resulting pore continuity and their dynamic during the cropping cycle. A total of 288 undisturbed soil samples were collected over two growing periods (2018–19 and 2019–20) on a long-term field experiment (~25 years old) in Agramunt, NE Spain. Three factors were investigated to observe their influence on the above-mentioned soil’s physical characteristics: two tillage systems (intensive tillage, IT and no-tillage, NT), two crop sequences (short fallow-maize, FM; legume-maize, LM) and two positions (within the row of crops, W-row; between rows of crops, B-row). Soil gas diffusivity was measured at five different soil water matric potentials (SWMP) (−10, −50, −100, −333 and −1000 cm H2O). LM crop sequence showed greater air-filled porosity, macroporosity and gas diffusivity, as well as enhanced pore continuity, than FM, especially at W-row. No significant differences were observed for measured gas diffusivity between NT and IT systems though NT had lower air-filled porosity and macroporosity (> 30 µm) compared to IT. Soil under NT showed greater pore continuity, particularly among macropores and less blocked pores than IT at higher SWMP (−10 cm H2O) but no difference was observed at lower SWMP (−1000 cm H2O) regardless of crop sequence and position. Air-filled porosity and pore continuity changes between maize planting and harvesting were greater under IT than NT. During the legume growing seasons, IT showed comparable pore continuity values to NT. In LM crop sequence soil gas transport was favorably affected alleviating the negative effect of intensive tillage on soil structural degradation. Long-term NT also improved soil structure as indicated by higher continuity of macropores, despite a decrease in air-filled porosity and macroporosity, but did not significantly lower gas diffusivity.

Fabrication of three-dimensional hierarchical porous 2D/0D/2D g-C3N4 modified MXene-derived TiO2@C: Synergy effect of photocatalysis and H2O2 oxidation in NO removal

A novel three-dimensional multi-level porous g-C3N4 modified MXene-derived TiO2@C aerogel (g-C3N4/TiO2@C aerogel) was synthesized for NO removal. Through SEM analysis, 2D g-C3N4 and 2D Ti3C2 nanosheets were constructed into an interconnected macroscopic framework with continuous macropores via ice template. OD TiO2 nanoparticles uniformly covered 2D C nanosheets with irregular mesopores and macropores in in-situ oxidation of Ti3C2 nanosheets by calcination via TEM analysis. g-C3N4/TiO2@C aerogel for photocatalytic activation of hydrogen peroxide (H2O2) had an excellent efficiency of 90.7% for NO removal at parts per million level. This efficiency was 4.9 times and 7.8 times that of g-C3N4/TiO2@C aerogel and H2O2 individually, due to the synergy between photocatalysis and H2O2 oxidation. Meantime, g-C3N4/TiO2@C aerogel exhibited an enhanced performance compared with g-C3N4 nanosheet (55.7%) and TiO2@C aerogel (38.5%). It was attributed to the large specific surface area (93.82 m2/g) with hierarchical mesoporous and macroporous structure and the 2D/OD/2D heterojunction of g-C3N4/TiO2@C aerogel, further enhancing electron-hole separation. The mechanism was hypothesized that g-C3N4/TiO2@C aerogel activated H2O2 to generate hydroxyl radicals (·OH) and superoxide radicals (·O2–) for oxidation of NO.

Soil Macropores Affect the Plant Biomass of Alpine Grassland on the Northeastern Tibetan Plateau

Macropores are an important part of soil structure. However, in alpine regions, the effects of soil macropores on soil properties and vegetation growth are not clear. We used the X-ray computed tomography (CT) method to obtain 3D images and visualize the distribution and morphology of soil macropores. By combining principal component analysis (PCA) and stepwise regression methods, we studied the relationships between soil macropores and both soil properties and vegetation growth in three types of grassland [alpine degraded steppe (ADS), alpine typical steppe (ATS), and alpine meadow steppe (AMS)] on the Tibetan Plateau. More tubular and continuous macropores occurred in the soil profiles of the AMS and ATS than in that of the ADS. In addition, the AMS soil had the highest macropore number (925 ± 189), while the ADS soil had the lowest macropore number (537 ± 137). PCA and correlation analysis suggested that macroporosity (MP) has significant positive correlations with the contents of soil organic matter, total nitrogen (TN), available phosphorus (AP) and total phosphorus (TP) (p < 0.05). The two parameters with the greatest influence on aboveground and belowground biomass were the shape factor (p < 0.05) and MP (p < 0.05), respectively. However, there was no significant correlation between plant diversity and soil macropores. We conclude that the irregularity of soil macropores restricts the growth space of roots and causes plants to sacrifice the accumulation of aboveground biomass for that of roots to find suitable sites for nutrient and water absorption.

Self-assembled block copolymer electrolyte membranes with silica network-derived nanochannels for all-solid-state supercapacitors

Amphiphilic Block copolymer (BC) membranes, where the BC hydrophilic domain offers a continuous pathway for fast ion transport, while the BC hydrophobic domain provides a scaffold for high mechanical strength, are being widely studied as promising materials for energy storage applications due to their unique morphology with 3-dimensionally continuous macropores. We design silica network-derived poly(styrene)-b-poly(2-vinylpyridine) BC-based hierarchically porous membranes containing high-conducting ionic liquids (ILs) as solid-state electrolytes via nonsolvent-induced phase separation and nonhydrolytic sol–gel process. The introduction of a silica nanoparticle network within the self-assembled BC leads to micro- and nano-scale porous structures. This provides the functionalized BC/IL-based electrolytes (BCEs) with high IL uptake (87 wt%), high dielectric constant (123), low activation energy for ion conduction (6.8 kJ/mol), and high room temperature ionic conductivity (∼10-3 S/cm, comparable to pure IL). The optimized BCE is assembled with activated carbon electrodes, allowing us to fabricate an all-solid-state supercapacitor. The device delivers a broad voltage window (2.5 V), high specific capacitance (∼90 F/g at 0.2 A/g), large energy (E) and power (P) densities (a maximum of E=19 Wh/kg, observed at P=224 W/kg, and a maximum of P=1.3 kW/kg, observed at E=4 Wh/kg), and remarkable electrochemical stability (capacitance retention = 90% for 600 cycles and 76% for 1000 cycles and coulombic efficiency = 100% for 1000 cycles at 0.2 A/g). Therefore, the combination of self-assembly, phase inversion, and in-situ hybridization-derived hierarchical dual-pore construction, providing rapid ion migration, could be a new approach to powering next-generation energy storage devices.

Polystyrene‐Supported PPh3 in Monolithic Porous Material: Effect of Cross‐Linking Degree on Coordination Mode and Catalytic Activity in Pd‐Catalyzed C−C Cross‐Coupling of Aryl Chlorides

AbstractHybridization of porous synthetic polymer and sophisticated ligands play an important role in transition‐metal catalysis for chemical transformations at laboratory and industrial levels. A monolithic porous polymer, which is a single piece with continuous macropores, is desired for high permeability, fast mass transfer properties, high stability, and easy modification. Herein, we first develop a monolithic porous polystyrene containing three‐fold cross‐linked PPh3 (M‐PS‐TPP) for transition‐metal catalysis. The monolithic and macroporous structure of M‐PS‐TPP was fabricated via polymerization‐induced phase separation using porogenic solvent. Moreover, the M‐PS‐TPP was synthesized using different feed ratios of divinylbenzene (DVB) for site‐isolation and mono‐P‐ligating behavior of PPh3. 31P CP/MAS NMR analysis revealed that the different selectivity of M‐PS‐TPPs was obtained in formation of mono‐P‐ligation toward PdII. The macroporous properties and controlled mono‐P‐ligating behavior of M‐PS‐TPP facilitated the challenging Pd‐catalyzed Suzuki‐Miyaura cross‐coupling reaction of chloroarenes.

Effects of large macropores on soil evaporation in salt marshes

The occurrence of macropores in salt marsh sediments is a natural and ubiquitous phenomenon. Although they are widely assumed to affect pore-water flow in salt marshes significantly, the mechanisms involved and their extent are not well understood. We conducted laboratory experiments and numerical simulations to examine the effect of macropores on soil evaporation. Soil columns packed with either sand or clay and with or without macropores were set up with watertables in the columns set at different levels. A high potential evaporation rate was induced by infrared light and a fan. The results showed that in the soil with a low saturated hydraulic conductivity (and thus a low water transport capacity), the macropore behaved as a preferential flow path for groundwater to recharge the surrounding soil during evaporation. The evaporated water originated largely from the macropore rather than the soil matrix, maintaining a high evaporation rate in comparison with a homogeneous soil. This effect was more pronounced for sediments with lower hydraulic conductivities and shallower watertables. These results improve our understanding of water flow and evaporation in salt marshes with continuous macropores between the soil surface and groundwater.

Effect of air mobility in a soil pipe on water flow through a model hillslope after pipe clogging

AbstractSoil pipes (continuous macropores expanding laterally in the soil subsurface) are a key factor controlling hillslope water cycles and sediment transport. Soil pipes usually enhance slope stability under rainfall events through their high water drainage ability, and pipe clogging by sediments is regarded as a risk for slope failure. In this study, we conducted a bench‐scale pipe clogging experiment to clarify the effect of air mobility in soil pipes on water flow and water pressure build‐up in the slope at the clogged point. Before pipe clogging, the soil pipe drained rainwater effectively and lowered the groundwater table. After the pipe clogging event, the mobility of air in the soil pipe before the clogging determined the water flow in the slope. When the air in the soil pipe connected to the atmosphere and moved freely, the water level in the soil pipe increased at the pipe clogging, and water pressure build‐up was limited near the pipe outlet. On the other hand, when air in the soil pipe was entrapped by the clogging, water pressure suddenly increased, and the groundwater table of the whole slope rose correspondingly. This study clearly demonstrated the importance of pipe morphology with respect to air connectivity between the pipe and atmosphere to elucidate the water flow and slope stability during the pipe clogging event. © 2019 John Wiley & Sons, Ltd.

3-D soil macropore networks derived from X-ray tomography in an alpine meadow disturbed by plateau pikas in the Qinghai Lake watershed, north-eastern Qinghai-Tibetan Plateau

The plateau pika (Ochotona curzoniae) is one of the main native soil faunas on the Qinghai-Tibet Plateau and plays a key role in the terrestrial ecosystem there. However, few studies have analysed the macroporosity of soils disturbed by plateau pikas in alpine meadows. The objective of this study was to examine the soil macropores in different parts of an alpine meadow in the Qinghai Lake watershed, namely, an original grassland, a new mound, an old mound, and a bald patch. In this investigation, soil cores were obtained from four different parts of an alpine meadow, namely, from under an original grassland, a new mound, an old mound, and a bald patch. A total of twelve soil cores (0–50 cm deep) were excavated, which included three replicates of each treatment. The soil architecture of each soil core was explored using X-ray computed tomography. The macroporosity decreased and then increased from the original grassland to the new mound, old mound, and bald patch. The soil macropores were most abundant up to a depth of 400 mm in the original grassland and up to a depth of 250 mm in the old mound and bald patch soils. The macropores in the original grassland were attributed to well-developed root systems. The smaller and less continuous macropores in the new mound, old mound, and bald patch soils were mainly disturbed by plateau pikas. It was expected that water would move preferentially through the macropores in the original grassland, while surface flow would more readily occur in the new mound, old mound, and bald patch soils, thereby leading to soil erosion.

Quantification of Soil Macropores at Different Slope Positions under Alpine Meadow Using Computed Tomography in the Qinghai Lake Watershed, NE Qinghai–Tibet

Soil macropores largely control fluid and solute transport and the runoff processes on the slopes. However, the characterization of soil macropores for different slope positions under alpine meadow conditions remains scarce, especially in the Qinghai Lake watershed. The objective of this study was to visualize and quantify the macropore characteristics of soils at different slope positions (i.e., the upper, middle and bottom slopes) in an alpine meadow in the Qinghai Lake watershed using X-ray computed tomography (CT). Nine soil cores (0–40 cm deep) were collected from the upper, middle and bottom slopes with three replicates per position, and cores were scanned with a GE HISPEED FX/I Medical Scanner. Macroporosity, length density, node density and tortuosity within the 40 cm soil profile were interpreted from the CT data to analyze the soil architecture. The results showed that the macroporosity decreased from the upper slope to the bottom slope. The macroporosity of soil on the upper slope was 50 times greater than that on the bottom slope, which can be attributed to the gravel in the former soil. The large number of continuous macropores and cracks concentrated in the deep soil layers (200–350 mm) of the upper slope can be attributed to the gravel layer. Most of the soil macropores under the middle and bottom slopes were distributed in the surface soil (0–150 mm), which can be attributed to the “mattic epipedon.” The soil macropores in the bottom slope, due to the well-developed root system, were more continuous and tubular than those in soils of the upper and middle slopes. It is expected that water can move preferentially through soil macropores on the upper and middle slopes compared to the bottom slope. Furthermore, due to its relatively low macroporosity the soil of the bottom slope contributes more to surface flow than those of middle and upper slopes.

Camponotus japonicus burrowing activities exacerbate soil erosion on bare slopes

As soil ecosystem engineers, ants considerably affect soil physical and chemical properties, and further accordingly affect soil erosion. However, few study was made on studying the effects of ant-burrowing activities on soil erosion previously. This study quantified the impacts of ant (Camponotus japonicus)-burrowing activities on runoff and soil erosion rates. Simulated laboratory rainfall experiments were undertaken on six soil tanks filled with clay-loam soil classified as a cumulic anthrosol, three of which introduced with ant colonies for two days and the other three were without ant colonies, under 40, 80, and 120 mm h−1 of rainfall intensities and a slope of 15°. Results showed that ants made mounds with a bulk density of 0.75 g cm−3, which was lower than that of the soil matrix, i.e. 1.34 g cm−3. Soil erosion rates for the tanks with ants were 6.78, 36.90, and 62.00 g m−2 min−1 under three rainfall intensities of 40, 80, and 120 mm h−1, which were much higher than those of 3.94, 23.49, and 44.48 g m−2 min−1 for the tanks without ants. Ant nests reduced the runoff rate by 31%, 20% and 13% compared with those without ants and enhanced the soil water storage within 90 cm depth. Ant nests played a positive role in soil water conservation due to the large nest entrance diameter and the continuous macropore network. However, the ant mounds provided a loose erodible material and changed micro-topography of the slope surface, thereby accelerating the rill formation and exacerbating soil erosion. This study can help understand the effects of burrowing insects on soil erosion, which is an important environmental problem on the Loess Plateau.

Porous interconnected NiCo2O4 nanosheets and nitrogen- and sulfur-codoped reduced graphene oxides for high-performance hybrid supercapacitors

We demonstrate a facile hydrothermal synthesis of the interconnected porous NiCo2O4 nanosheets for hybrid supercapacitor applications. The as-synthesized NiCo2O4 nanosheets show a high specific capacitance of 3137 F g−1 at a current density of 2 A g−1, which is much greater than 1916 and 1251 F g−1 of Co3O4 and NiO, respectively. Interestingly, the total specific capacitance of the NiCo2O4 is almost close to the sum of the specific capacitance of the NiO and Co3O4. Furthermore, a hybrid supercapacitor is configured with the NiCo2O4 nanosheets and the nitrogen- and sulfur-codoped reduced graphene oxide as the positive and negative electrodes, respectively. This hybrid supercapacitor delivers a maximum energy density of 33.64 W h kg−1 at a power density of 1196 W kg−1 and excellent long-term cyclic stability over 12,000 charge/discharge cycles at the enlarged voltage window of 1.5 V. The remarkable supercapacitive performances of the hybrid device are attributed to the interconnected porous structure of NiCo2O4 nanosheets and three-dimensional continuous macropores of codoped reduced graphene oxides.

An experimental study on microstructure of leachate-polluted stabilized clay

Clay-solidified grouting curtain (CSGC) is a new kind of vertical barrier for remediating unregulated waste disposal sites in China that combines vertical-barrier and cement-based solidification-stabilization treatment techniques. The cement, stabilizing agents and landfill leachate clearly influence penetration. Although CSGC is becoming widely used because it is effective and economical, little is known about how it works. There is no clear consensus on the penetration mechanism, especially under actual continuous leachate percolation. The present work, therefore, studies the microstructure of CSGC under actual continuous leachate percolation. The cement and self-development stabilizing agents (CERSM-B) and their combined effect on the cumulative intrusion and pore size distribution were investigated using mercury intrusion porosimetry and scanning electron microscope images. The experimental results demonstrated that the unhydrated cement particles first create a large pore space. With increasing cement content, cementation products fill the large pores, thus decreasing the total pore volume. Fine-needle hydration ettringite crystal and calcium silicate hydrate gels are found when the cement content is below 15%. Stabilizing agents (CERSM-B) play an important role in the microstructure of CSGC. A close structure of flaky crystals with small, infrequent pores can be observed in samples treated with stabilizing agents (CERSM-B). However, adding too many stabilizing agents (CERSM-B) may increase the continuity of macropores. The peak pore size distribution and corresponding pore size increase with increasing dosage of stabilizing agents (CERSM-B). In engineering applications, the recommended range of cement and stabilizing agents (CERSM-B) is 15–20% percent clay and 7.5–10% cement.

Synthesis of hierarchically porous MgO monoliths with continuous structure via sol–gel process accompanied by phase separation

Hierarchically porous magnesium oxide, MgO, monoliths with a well-defined continuous macroporous structure have been synthesized via the sol–gel route accompanied by phase separation. Magnesium chloride hexahydrate was used as a precursor, and propylene oxide was used as an acid scavenger to raise the pH of a reaction solution homogenously. In order to obtain a crack-free monolith after heating in air, poly(vinylpyrrolidone), PVP, was employed as a scaffold of the skeleton as well as a phase separation controller to form the continuous macropores with higher homogeneity. Due to the moderate hydrogen-bonding interaction with magnesium hydroxide, PVP reinforces the gel network essentially composed of fine grained magnesium hydroxide. Even after the removal of all organic components by calcination, the porous gel samples maintained their monolithic form. On the other hand, an additional incorporation of 1,3,5-benzenetricarboxylic acid, H3BTC, was found to be effective in suppressing the oriented growth of the micrometer-sized crystalline phase. The polycrystalline MgO monoliths with specific surface area of 185, 64, and 48 m2 g−1 were prepared after heating at 400, 500, and 600 °C in air, respectively.

Free‐Standing Air Cathodes Based on 3D Hierarchically Porous Carbon Membranes: Kinetic Overpotential of Continuous Macropores in Li‐O2 Batteries

AbstractFree‐standing macroporous air electrodes with enhanced interfacial contact, rapid mass transport, and tailored deposition space for large amounts of Li2O2 are essential for improving the rate performance of Li‐O2 batteries. An ordered mesoporous carbon membrane with continuous macroporous channels was prepared by inversely topological transformation from ZnO nanorod array. Utilized as a free‐standing air cathode for Li‐O2 battery, the hierarchically porous carbon membrane shows superior rate performance. However, the increased cross‐sectional area of the continuous macropores on the cathode surface leads to a kinetic overpotential with large voltage hysteresis and linear voltage variation against Butler–Volmer behavior. The kinetics were investigated based on the rate‐determining step of second electron transfer accompanied by migration of Li+ in solid or quasi‐solid intermediates. These discoveries shed light on the design of the air cathode for Li‐O2 batteries with high‐rate performance.

Free-Standing Air Cathodes Based on 3D Hierarchically Porous Carbon Membranes: Kinetic Overpotential of Continuous Macropores in Li-O2 Batteries.

Free-standing macroporous air electrodes with enhanced interfacial contact, rapid mass transport, and tailored deposition space for large amounts of Li2 O2 are essential for improving the rate performance of Li-O2 batteries. An ordered mesoporous carbon membrane with continuous macroporous channels was prepared by inversely topological transformation from ZnO nanorod array. Utilized as a free-standing air cathode for Li-O2 battery, the hierarchically porous carbon membrane shows superior rate performance. However, the increased cross-sectional area of the continuous macropores on the cathode surface leads to a kinetic overpotential with large voltage hysteresis and linear voltage variation against Butler-Volmer behavior. The kinetics were investigated based on the rate-determining step of second electron transfer accompanied by migration of Li+ in solid or quasi-solid intermediates. These discoveries shed light on the design of the air cathode for Li-O2 batteries with high-rate performance.

Easily separated and recyclable amino-functionalized porous SiO2 beads with 3D continuous meso/macropore channels

Amino-functionalized porous SiO2 beads with a diameter of 200—800 μm(PSB-NH2) have been success-fully synthesized by grafting 3-aminopropyl-triethoxysilane onto meso/macroporous silica beads(PSB), in which the PSB was prepared by hydrothermal synthetic method with a porous hard template anion-exchange resin. The as-prepared materials were characterized by means of nitrogen sorption and transmission electron micrographs(TEM), showing the presence of 3D interconnected and continuous large mesopores and macropores inside. The beads were used to catalyze Knoevenagel condensation and proved to be highly active and selective due to the high accessibility of the reactants to the amino groups via the continuous 3D meso/macopores. Notably, such material in bead format facilitates the extremely straightforward separation from reaction solution without any centrifugation or filtration. Moreover, PSB-NH2 proved to be a stable catalyst via leaching experiment test, and can be easily recovered and reused without significant loss of activity in successive catalytic cycles.

Characterising and linking X-ray CT derived macroporosity parameters to infiltration in soils with contrasting structures

Soils deliver the regulating ecosystem services of water infiltration and distribution, which can be controlled by macropores. Parameterizing macropore hydraulic properties is challenging due to the lack of direct measurement methods. With tension-disc infiltrometry hydraulic properties near saturation can be measured. Differentiating between hydrologically active and non-active pores, at a given water potential, indirectly assesses macropore continuity. Water flow through macropores is controlled by macropore size distribution, tortuosity, and connectivity, which can be directly derived by X-ray computed tomography (CT). Our objective was to parameterize macropore hydraulic properties based on the imaged macropore network of three horizons of an Andosol and a Gleysol. Hydraulic conductivity Kunsat was derived from infiltration measurements. Soil cores from the infiltration areas were scanned with X-ray CT. Kunsat was significantly higher in the Andosol than in the Gleysol at all water potentials, and decreased significantly with depth in both soils. The in situ measurements guided the definition of new macroporosity parameters from the X-ray CT reconstructions. For the Andosol, Kunsat was best predicted using the imaged-limited macroporosity. A low total macroporosity, coupled with a high macropore density, indicated the abundance of smaller macropores, leading to homogeneous matrix flux. Imaged macropores were not well connected. In contrast, the Gleysol had a bi-modal macropore system with few very large, but well-connected macropores. Kunsat was best predicted using the imaged macroporosity consisting only of macropores with diameters between 0.75 and 3mm. Our research demonstrates that linking traditional soil physical measurements with soil-visualization techniques has a huge potential to improve parameterizing macropore hydraulic properties. The relevance of the relationships found in this study for larger scales and other soil types still needs to be tested, for example by a multi-scale investigation including a much wider range of different soils.

Determination of the role of entrapped air in water flow in a closed soil pipe using a laboratory experiment

AbstractSoil pipes, continuous macropores parallel to the soil surface, are an important factor in hillslope hydrological processes. However, the water flow dynamics in soil pipes, especially closed soil pipes, are not well understood. In this study, the water and air dynamics within closed soil pipes have been investigated in a bench‐scale laboratory experiment by using a soil box with an artificial acrylic soil pipe. In order to grasp the state of water and air within the soil pipe, we directly measured the existing soil pipe flow and air pressure in the soil pipe. The laboratory experiment showed that air in the soil pipe had an important role in the water flow in the closed soil pipe. When air entrapment occurred in the soil pipe before the soil matrix around the soil pipe was saturated with water, water intrusion in the soil pipe was prevented by air entrapped in the pipe, which inhibited the soil pipe flow. This air entrapment in the soil pipe was controlled by the soil water and air flow. Moreover, after the soil pipe flow started, the soil pipe was not filled completely with water even when the soil pipe was completely submerged under the groundwater table. The entrapped air in the soil pipe prevented further water intrusion in the soil pipe.

New platform for simple and rapid protein-based affinity reactions

We developed a spongy-like porous polymer (spongy monolith) consisting of poly(ethylene-co-glycidyl methacrylate) with continuous macropores that allowed efficient in situ reaction between the epoxy groups and proteins of interest. Immobilization of protein A on the spongy monolith enabled high-yield collection of immunoglobulin G (IgG) from cell culture supernatant even at a high flow rate. In addition, immobilization of pepsin on the spongy monolith enabled efficient online digestion at a high flow rate.