Tubular Pores Research Articles

Formation of supramolecular structure in alginate/chitosan aerogel materials during sol-gel synthesis

Alginate/chitosan (AlgNa/Cht) aerogels and carbogels with a developed micro-mesoporous structure were produced. For the first time, the classical scheme, including the sol-gel process and supercritical fluid drying, was applied to obtain the two-component AlgNa/Cht aerogel materials with predicted properties. The obtained aerogels and carbogels have a specific surface area up to 399 m2g−1 and 549 m2g−1, respectively, and tubular pore structure. The morphological characteristics of the samples were investigated by atomic force microscopy and by scanning electron microscopy. It was shown that carbogels have narrow globular particle size distribution (35–45 nm). The synthesis conditions (critical concentration and syneresis region) are established under which the coagulum is formed in the form of an interpolyelectrolyte complex. The calcium carbonate impregnation into AlgNa/Cht system leads to an almost instantaneous formation of a hydrogel. Moreover, it allows changing material structure due to the additional nodes of the fluctuation mesh of engagement, which leads to an increase in the sizes of associative structural formations of aerogel materials, its strength, and high dimensional stability. The use of the template allowed to increase the specific surface area and the mesopores volume in the of the carbogels in 1.5–2 times. Due to such structure, the 1 g of aerogel material retains 20–35 g of water while maintaining shape. The shape of the monolith in the carbogel is maintained. Obtained AlgNa/Cht aerogels are of medical and biological interest.

Biomimetic Bilayer Scaffold as an Incubator to Induce Sequential Chondrogenesis and Osteogenesis of Adipose Derived Stem Cells for Construction of Osteochondral Tissue.

Toward osteochondral tissue construction, the present study introduced a bilayer scaffold to induce sequential chondrogenesis and osteogenesis of stem cells in vitro. Two scaffolds that are both based on poly(l-glutamic acid) (PLGA) and chitosan (CS) were combined to form the bilayer scaffold. The cartilage region was the covalently cross-linked PLGA/CS hydrogel with a tubular pore structure, possessing a swollen network to prevent cellular adhesion, while inducing spontaneous cellular aggregate formation. The bone region was the electrostatically cross-linked PLGA-grafted nano hydroxyapatite (nHA-g-PLGA)/CS scaffold, which supported cellular adhesion and spreading. Human adipose derived stem cells (hASCs) were seeded into the cartilage region and observed to aggregate, formimg multicellular spheroids, which subsequently fused to rod-like aggregates with a larger size. At the same time, hASCs in aggregates crossed the interface and entered the bone region, presenting adhesion and spreading. With the induction of bone morphogenetic protein 2 (BMP-2) and insulin-like growth factor 1 (IGF-1) during the first 14 days and BMP-2 alone during the last 14 days, hASCs aggregates in the cartilage region underwent chondrogenesis, expressing an abundant cartilage matrix including glycosaminoglycans (GAGs) and type II collagen (COL II) at 28 days. The chondrogenic induced hASCs migrated in the bone region turned to osteogenesis at 28 days, which was associated with their large spreading area and the switch of the induce factor. Thus, the present bilayer scaffold induced the different distribution of hASCs, resulting in subsequent chondrogenesis and osteogenesis, realizing osteochondral tissue construction in vitro.

Pressure-dependent bulk compressibility of a porous granular material modeled by improved contact mechanics and micromechanical approaches: Effects of surface roughness of grains

The change of the mechanical properties of granular materials with pressure is an important topic associated with many industrial applications. In this paper we investigate the influence of hydrostatic pressure (Pe) on the effective bulk compressibility (Ceff) of a granular material by applying two modified theoretical approaches that are based on contact mechanics and micromechanics, respectively. For a granular material composed of rough grains, an extended contact model is developed to elucidate the effect of roughness of grain surfaces on bulk compressibility. At relatively low pressures, the model predicts that the decrease of bulk compressibility with pressure may be described by a power law with an exponent of -1/2 (i.e., Ceff ∝Pe−1/2), but deviates at intermediate pressures. At elevated pressures beyond full contact, bulk compressibility remains almost unchanged, which may be roughly evaluated by continuum contact mechanics. As an alternative explanation of pressure-dependent bulk compressibility, we suggest a micromechanical model that accounts for effects of different types of pore space present in granular materials. Narrow and compliant inter-granular cracks are approximated by three-dimensional oblate spheroidal cracks with rough surfaces, whereas the equant and stiff pores surrounded by three and four neighboring grains are modeled as tubular pores with cross sections of three and four cusp-like corners, respectively. In this model, bulk compressibility is strongly reduced with increasing pressure by progressive closure of rough-walled cracks. At pressures exceeding crack closure pressure, deformation of the remaining equant pores is largely insensitive to pressure, with almost no further change in bulk compressibility. To validate these models, we performed hydrostatic compression tests on Bentheim sandstone (a granular rock consisting of quartz with high porosity) under a wide range of pressure. The relation between observed microstructures and measured pressure-dependent bulk compressibility is well explained by both suggested models.

Liquid Phase Synthesis and Morphological Observation of BaTiO₃-CoFe₂O₄ Nanocomposite Films.

A novel and inexpensive fabrication method of multiferroic nanocomposite films via liquid-phase formation is demonstrated in this work. Well-aligned anodized TiO₂ nanotube arrays on a Ti substrate were used as the core template. The anodized TiO₂ nanotube arrays were then hydrothermally treated in Ba(OH)₂ aqueous solution to form BaTiO₃ (BTO) nanotube arrays. The average pore diameter and thickness of the BTO nanotube arrays obtained were approximately 50~70 nm and 2~4 μm, respectively. The BTO nanotube arrays were then dip-coated with CoFe₂O₄ (CFO) sol with the assistance of vaccum impregnation equipment to enable the penetration of CFO sol into the tubular pores of the BTO nanotube arrays. The good distribution of CFO in the BTO nanotube arrays was confirmed by electron microscopy accompanied with elemental analysis. The good crystallinity of CFO and BTO in the nanocomposite was confirmed by X-ray diffraction, and the nanocomposite film exhibited anisotropic ferrimagnetic properties upon an in plane and out-plane applied magnetic field.

Tailoring three-dimensional interconnected nanoporous graphene micro/nano-foams for lithium-sulfur batteries

Three-dimensional interconnected nanoporous graphene (NPG) microfoams and nanofoams are developed via a new approach of solid-state catalytic growth. Both NPG microfoam and nanofoam exhibit similar nanoporous structures that contain close tubular pores and open non-tubular pores but with different particle sizes. As electrochemical reactors for sulfur cathodes, sulfur is encapsulated inside the tubular pores. It is found that NPG nanoreactors can enhance the electrochemical performances in comparison with NPG microreactors, including improved reversible capacities, cyclic performances and rate performances in particular. The electrochemical impedance spectroscopy analysis reveals that NPG nanoreactors facilitate Li+ transportation and decrease the charge-transfer resistance in comparison with the microreactors, promoting the redox kinetics of multi-step conversions between sulfur and lithium sulfides. This work demonstrates a significant particle size effect of nanoporous graphene on the Li–S electrochemistry and can be useful for designing Li–S batteries as well as other electrochemical energy storage systems.

Exploration of accessibility of internal pore surface by using rigid nanoparticles as a probe for constructing the integrated nanocomposites

Many mesoporous materials with different morphologies, dimensions, pore sizes and structures have been fabricated and served as carriers to load a wide range of guest species. The high accessibility of pore interiors should be of very significance for efficient loading in the nanocarriers and resultant performance of the formed nanocomposites. In this work, by electrostatic self-assembly, the rigid nanoparticles (NPs) were used as probes to detect the accessibility of internal surface of different pore channels of two typical porous materials, i.e., conventional mesoporous silica nanospheres (MSNs) with uniform hexagonal ordered mesopores and recently created dendritic porous silica NPs (DPSNs) with center-radial porous structure. Interestingly, even 1.6 ± 0.4 nm of ultrafine Au NPs have an uneven and low density distribution on the internal pore surface of MSNs owing to small tubular pores with only two openings. On the contrary, the rigid NPs with different particle sizes from 1.6 ± 0.4 nm to 7.8 ± 1.9 nm can enter DPSNs through open center-radial large pores with 360° diffusion direction, and achieve a high density and well-dispersed loading on the surface of internal pore channels. Besides, based on the size effect, the integrated DPSNs-NH2@Au@Pt nanocomposite with hierarchical spatial distributions of large Au NPs on particle surface and small Pt NPs on both internal pore surface and particle surface were successfully constructed. These results provide an important insight into the accessibility of internal pore surface toward rigid NPs and the smart construction of multifunctional nanocomposites.

Enhanced thermoelectric and mechanical properties in hierarchical tubular porous cuprous selenide

Superionic thermoelectric Cu2Se bulks are successfully acquired via an identical gas reinforced eutectic transformation (gasar) process based on its melting-congruent nature. The gasar synthesis process introduces tubular pores to Cu2Se matrix, which have hierarchical size and corrugated surface, and are distributed homogeneously and isotopically. The Cu2Se bulk with such a unique porous structure shows enhanced thermoelectric figure-of-merit up to ∼2.1 at 873 K owing to the conspicuously reduced thermal conductivity, which can be attributed to the increased phonon scattering. Moreover, the porous Cu2Se bulk also possesses higher mechanical robustness compared with traditional porous-structured material because of the corrugated surface, which is promising for making thermoelectric modules.

Long cycle performance folium cycas biochar/S composite material for lithium-sulfur batteries

Biomass has rich porous texture and unique physical and chemical properties, so it is widely used to enhance the electrochemical performances of lithium-sulfur batteries. In this paper, porous biochar is fabricated by easily obtained folium cycas. Acetic acid (HAc) is used to clean the ash content in cavity and solve the problem of pore blockage. The results showed that the folium cycas biochar (FCB) treated with HAc increased the specific surface area by 44.7% (2954 m2/g) and the cumulative pore volume by 67.5% (1.39 cm3/g). The FCB has rich nano-scale meso/microporous tubular pores which provide a natural high-efficiency space for sulfur storage and buffer the volume expansion, so that the prepared composite cathode material of FCB/S has a first discharge capacity of up to 1317 mAh/g and stable at 910 mAh/g after 5 cycles. The capacity can still reach 790 mAh/g after 200 cycles with an attenuation rate of only 0.068% for each cycle.

Nanomachines and Other Caps on Mesoporous Silica Nanoparticles for Drug Delivery.

Mesoporous silica nanoparticles (MSNs) are delivery vehicles that can carry cargo molecules and release them on command. The particles used in the applications reported in this Account are around 100 nm in diameter (about the size of a virus) and contain 2.5 nm tubular pores with a total volume of about 1 cm3/g. For the biomedical applications discussed here, the cargo is trapped in the pores until the particles are stimulated to release it. The challenges are to get the particles to the site of a disease and then to deliver the cargo on command. We describe methods to do both, and we illustrate the applicability of the particles to cure cancer and intracellular infectious disease. Our first steps were to design multifunctional nanoparticles with properties that allow them to carry and deliver hydrophobic drugs. Many important pharmaceuticals are hydrophobic and cannot reach the diseased sites by themselves. We describe how we modified MSNs to make them dispersible, imagable, and targetable and discuss in vitro studies. We then present examples of surface modifications that allow them to deliver large molecules such as siRNA. In vivo studies of siRNA delivery to treat triple-negative breast and ovarian cancers are presented. The next steps are to attach nanomachines and other types of caps that trap drug molecules but release them when stimulated. We describe nanomachines that respond autonomously (without human intervention) to stimuli specific to disease sites. A versatile type of machine is a nanovalve that is closed at neutral (blood) pH but opens upon acidification that occurs in endolysosomes of cancer cells. Another type of machine, a snap-top cap, is stimulated by reducing agents such as glutathione in the cytosol of cells. Both of these platforms were studied in vitro to deliver antibiotics to infected macrophages and in vivo to cure and kill the intracellular bacteria M. tuberculosis and F. tularensis. The latter is a tier 1 select agent of bioterrorism. Finally, we describe nanomachines for drug delivery that are controlled by externally administered light and magnetic fields. A futuristic dream for nanotherapy is the ability to control a nano-object everywhere in the body. Magnetic fields penetrate completely and have spatial selectivity governed by the size of the field-producing coil. We describe how to control nanovalves with alternating magnetic fields (AMFs) and superparamagnetic cores inside the MSNs. The AMF heats the cores, and temperature-sensitive caps release the cargo. In vitro studies demonstrate dose control of the therapeutic to cause apoptosis without overheating the cells. Nanocarriers have great promise for therapeutic applications, and MSNs that can carry drugs to the site of a disease to produce a high local concentration without premature release and off-target damage may have the capability of realizing this goal.

El papel de los hongos en la conservación de Andosols: estudio de caso en Tlaxcala, México

Tlaxcala state, Mexico, show environmental problems related to soil erosion; however, in some areas of Andosols, with pine forests and even in agricultural areas, it has been observed that their degradation is minimal. The abundant presence of mycelium even in subsurface horizons can be the reason why soils are conserved. The objectives of this study were to characterize the edaphic properties in different geo-morphological positions, to identify the species of arbuscular mycorrhizal fungi (AMF) and to determine the relationship of the mycelium with aggregates and elementary particles in a Vitric Andosols of Calpulalpan, Tlaxcala, Mexico. The results showed that soils have different sequences and thicknesses of ashes and lapillis pomaceous and have moderate to high fertility. The crumbly structure dominated in upper horizons and simple granular in sub-horizons. The horizons showed high retention of humidity and permeability facilitating mycelial development and formation of AMF spores up to 120 cm deep. Ten species of AMF were recorded and the most abundant was Funneliformis mosseae. The micro-morphological analysis showed different relationships between the mycelium, horizon and soil particles, with organic waste (horizon O), with macro and micro aggregates (horizons A and B), with allophane and imogolite (horizons B) and lapillis (horizon C). The fungal mycelium forms networks throughout the soil, and in the lapillis it inserts the pumice particles (like a rosary) through the tubular vesicular pores, which provides stability to the Andosols and prevents their degradation.

Synthesis and Characterization of Ru-Loaded Anodized Aluminum Oxide for Hydrogenation Catalysis.

Anodized aluminum oxides (AAOs) are synthesized and used as catalyst support in combination with Ru as metal in hydrogenation catalysis. SEM and TEM analysis of the as‐synthesized AAOs reveal uniform, ordered nanotubes with pore diameters of 18 nm, which are further characterized with Kr physisorption, XRD and FTIR spectroscopy. After impregnation of the AAOs with Ru, the presence of Ru nanoparticles inside the tubular pores is evidenced clearly for the first time via HAADF‐STEM‐EDX. The Ru−AAOs have been tested for catalytic activity, which showed high conversion and selectivity for the hydrogenation of toluene and butanal.

Nanoporous Carbon: Liquid-Free Synthesis and Geometry-Dependent Catalytic Performance.

Nanostructured carbons with different pore geometries are prepared with a liquid-free nanocasting method. The method uses gases instead of liquid to disperse carbon precursors, leach templates, and remove impurities, minimizing synthetic procedures and the use of chemicals. The method is universal and demonstrated by the synthesis of 12 different porous carbons with various template sources. The effects of pore geometries in catalysis can be isolated and investigated. Two of the resulted materials with different pore geometries are studied as supports for Ru clusters in the hydrogenolysis of 5-hydroxymethylfurfural (HMF) and electrochemical hydrogen evolution (HER). The porous carbon-supported Ru catalysts outperform commercial ones in both reactions. It was found that Ru on bottleneck pore carbon shows a highest yield in hydrogenolysis of HMF to 2,5-dimethylfuran (DMF) due to a better confinement effect. A wide temperature operation window from 110 to 140 °C, with over 75% yield and 98% selectivity of DMF, has been achieved. Tubular pores enable fast charge transfer in electrochemical HER, requiring only 16 mV overpotential to reach current density of 10 mA·cm-2.

Functionalization of AuMSS nanorods towards more effective cancer therapies

The application of nanoparticles as selective drug delivery platforms arises as one the most promising therapeutic strategies in the biomedical field. Such systems can encapsulate drugs, prevent its premature degradation, transport and promote the drugs specific delivery to the target site. Among the different nanostructures, gold-core mesoporous silica shell (AuMSS) nanorods have been one of the most explored due to their unique physical and chemical properties. The mesoporous silica biocompatibility, high surface area that can be easily functionalized, tubular pores that can store the drugs, conjugated with the intrinsic capacity of gold nanorod to absorb near-infrared radiation, allows the combination of hyperthermia (i.e., photothermal effect) with drug delivery, making them a nanoplatforms with a huge potential for cancer therapy. Nevertheless, the successful application of AuMSS nanoparticles as an effective cancer nanomedicine is hindered by the uncontrolled release of the therapeutic payloads, limited blood circulation time and unfavorable pharmacokinetics. In this review, an overview of the modifications performed to improve the AuMSS nanorods application in nanomedicine is provided, highlighting the practical approaches that enhanced the AuMSS nanorods targeting, responsiveness to different stimuli, and blood circulation time. Further, the basics of AuMSS nanorods synthesis procedures, general properties, and its application in cancer therapy are also described.

Framework disorder and its effect on selective hysteretic sorption of a T-shaped azole-based metal-organic framework.

Metal-organic frameworks with highly ordered porosity have been studied extensively. In this paper, the effect of framework (pore) disorder on the gas sorption of azole-based isoreticular Cu(II) MOFs with rtl topology and characteristic 1D tubular pore channels is investigated for the first time. In contrast to other isoreticular rtl metal-organic frameworks, the Cu(II) metal-organic framework based on 5-(1H-imidazol-1-yl)isophthalate acid has a crystallographically identifiable disordered framework without open N-donor sites. The framework provides a unique example for investigating the effect of pore disorder on gas sorption that can be systematically evaluated. It exhibits remarkable temperature-dependent hysteretic CO2 sorption up to room temperature, and shows selectivity of CO2 over H2, CH4 and N2 at ambient temperature. The unique property of the framework is its disordered structure featuring distorted 1D tubular channels and DMF-guest-remediated defects. The results imply that structural disorder (defects) may play an important role in the modification of the performance of the material.

Three-dimensional micron-porous graphene foams for lightweight current collectors of lithium-sulfur batteries

This paper reports a three-dimensional (3D) stochastic bicontinuous micron-porous graphene foam (3D-MPGF) developed as lightweight binder-free current collectors for sulfur cathodes of lithium-sulfur batteries. 3D-MPGF is synthesized by a facile process that originally combines the synthesis of porous metals by the reduction of metallic salts and chemical vapor deposition (CVD) growth of graphene in a continuous route. 3D-MPGF presents micron-porous structure with both interconnected tubular pores and nontubular pores of sizes from hundreds nanometers to several microns. By adjusting CVD time, the thickness of graphene wall is tunable from few atomic layers to ten layers. Raman results prove a high crystalline of 3D-MPGF. Attributed to the low density and high quality, 3D-MPGF can be used as promising lightweight binder-free current collectors. The 3D-MPGF loaded with S of 2.5 mg cm−2 exhibited an ultrahigh initial capacity of 844 mAh g−1 (of electrode), and maintain at 400 mAh g−1 after 50 cycles at 0.1C (167 mA g−1). With increasing the loading of S, the electrodes present higher areal capacities. When the loading of S is 13 mg cm−2, the areal capacity of 3D-MPGF/S reaches 5.9 mAh cm−2 after 50 cycles at 0.1C. The use of 3D micron-porous graphene foam proves considerably enhanced gravimetric capacity densities (of overall electrode), which can be a direction not only for batteries but also for other energy storage devices.

X-ray study of anisotropically shaped metal halide perovskite nanoparticles in tubular pores

Recently, we have reported that metal halide perovskite nanoparticles formed in nanoporous alumina and silicon thin films exhibit blue shifted photoluminescence due to spatial confinement, thus allowing for color tuning of the emission by varying the pore size. While perovskite nanoparticles grown in nanoporous alumina films have been integrated into LEDs, similar approaches have failed with silicon. Here, we report the results of investigating the structure of the alumina pore system and the perovskite crystallites forming within. We use two x-ray diffraction techniques, namely, small-angle x-ray scattering (SAXS) and high-energy microbeam wide-angle x-ray scattering (WAXS). SAXS reveals that the alumina pore system diffracts like regularly arranged tubes with the average diameter and nearest neighbor distance of 12 nm and 20 nm, respectively. High-energy microbeam WAXS shows that perovskite nanoparticles within the nanoporous alumina have a distinctly anisotropic shape with the average particle length along and perpendicular to the pore axis of 26 nm and 13 nm, respectively. In contrast, no shape anisotropy has been detected for nanoparticles inside the silicon pores in a previous study. This suggests that utilizing nanoporous alumina has a twofold advantage. First, the tubular alumina pores, spanning the entire insulating film, offer percolated paths for the perovskite to fill. Second, the elongation of the nanoparticles in the tubular alumina pores can be expected to aid device performance as the length of the nanoparticles approaches the active layer thickness (ca. 40 nm) of LEDs, while the small diameter of the crystallites accounts for the observed blue shifted emission.

Textural Insights Into the Evolving Lava Dome Cycles at Santiaguito Lava Dome, Guatemala

The structures and textures preserved in lava domes reflect underlying magmatic and eruptive processes, and may provide evidence of how eruptions initiate and evolve. This study explores the remarkable cycles in lava extrusion style produced between 1922 and 2012 at the Santiaguito lava dome complex, Guatemala. By combining an examination of eruptive lava morphologies and textures with a review of historical records, we aim to constrain the processes responsible for the range of erupted lava type and morphologies. The Santiaguito lava dome complex is divided into four domes (El Caliente, La Mitad, El Monje, El Brujo), containing a range of proximal structures (e.g. spines) from which a series of structurally contrasting lava flows originate. Vesicular lava flows (with a’a like, yet non-brecciated flow top) have the highest porosity with interconnected spheroidal pores and may transition into blocky lava flows. Blocky lava flows are high volume and texturally variable with dense zones of small tubular aligned pore networks and more porous zones of spheroidal shaped pores. Spines are dense and low volume and contain small skeletal shaped pores, and subvertical zones of sigmoidal pores. We attribute the observed differences in pore shapes to reflect shallow inflation, deflation, flattening or shearing of the pore fraction. Effusion rate and duration of the eruption define the amount of time available for heating or cooling, degassing and outgassing prior to and during extrusion, driving changes in pore textures and lava type. Our new textural data when reviewed with all the other published data allows cyclic models to be developed. The cyclic eruption models are influenced by viscosity changes resulting from (1) initial magmatic composition and temperature, and (2) effusion rate which in turn affects degassing, outgassing and cooling time in the conduit. Each lava type presents a unique set of hazards and understanding the morphologies and dome progression is useful in hazard forecasting.

Preparation of BaTiO3 Nanotube Arrays, CoFe2O4 Nanoparticles and Their Composites

Multiferroic nanocomposites which possess both ferroelectric and ferromagnetic properties are attracting much attention because of their scientific interest and significant technological promise in novel multifunctional devices. In this work, multiferroic nanocomposites are targeted by anodization of Ti sheets to get TiO2 nanotubes followed by hydrothermal treatment to form BaTiO3 nanotube arrays, which were then used as a component to fabricate multiferroic nanocomposites through electrophoretic deposition (EPD) of CoFe2O4 nanoparticles into the tubular pores. Successful formation of BaTiO3 nanotube arrays and CoFe2O4 nanoparticles were achieved. The morphologies and crystal structure of BaTiO3 nanotube arrays were analyzed by a scanning electron microscope (SEM) and an X-ray diffractometer (XRD). Simulation of EPD of CoFe2O4 nanoparticles into BaTiO3 nanotube arrays was also performed in order to predict and improve the susceptibility of forming a desired composite layer.

Coordination chemistry of flexible benzene-1,3,5-tricarboxamide derived carboxylates; notable structural resilience and vaguely familiar packing motifs.

Flexible benzene-1,3,5-tricarboxamides (BTAs), organic species well-known for their tendencies to form functional soft-materials by virtue of their complementary hydrogen bonding, are explored as structurally reinforcing supramolecular building blocks in porous coordination polymers. We report the synthesis and characterisation of two related, carboxylate-terminated BTA derivatives, and the structure and functionality of their polymeric Cd(ii) complexes. The polycarboxylate ligand benzene-1,3,5-tricarboxamide tris(phenylacetic acid) H3L1 was prepared, and the analogous trimethyl benzene-1,3,5-tricarboxamide tris acetate Me3L2 was prepared and its single crystal structure elucidated. On reaction with cadmium nitrate in a DMF/H2O mixture, each BTA compound yielded coordination polymer species with columnar packing motifs comparable to the familiar BTA triple helix seen in purely organic systems. In the case of Me3L2, this transformation was achieved through a convenient in situ ester hydrolysis. Complex 1 is a 2-dimensional layered material containing tubular intralayer pores, in which amide-amide hydrogen bonding is a notable structural feature. In contrast, the structure of 2 contains no amide-amide hydrogen bonding, and instead a columnar arrangement of ligand species is linked by trinuclear Cd(ii) cluster nodes into a densely packed three-dimensional framework. The crystal structures revealed both materials exhibited significant solvent-accessible volume, and this was probed with thermal analysis and CO2 and N2 adsorption experiments; complex 2 showed negligible gas uptake, while compound 1 possesses an unusually high CO2 capacity for a two-dimensional material with intralayer porosity and surprising structural resilience to guest exchange, evacuation and exposure to air.

Rotating Cylinder Microfiltration of Oil–in–Water Emulsion Using Novel Slotted Pore Filter

Nowadays, oil–in–water emulsion has become an important topic in petroleum industry, which produces oil–inwater emulsion in the recovery of crude oil. Oil–in–water emulsion produced in crude oil recovery causes problems at different stages of the production in the petroleum industry. Recently, microfiltration has been applied in the separation of oil from water. In filtration of oil–in–water emulsion, there is the possibility of oil drops deforming and squeezing through the slot of membrane so the separation efficiency will decrease. This research has studied cross flow filtration of oil–in–water emulsion in a rotating system and also visualized the interaction of oil drops and slot shaped membrane pores. The drop or bubble–slot experiment used a slot with different width. It has been found that the squeezing of an oil drop in the slot is really determined by the pressure applied and velocity of the surrounding fluid. Cross flow microfiltration experiment was conducted using tubular slotted pore membrane with rotation to generate shear on the surface of membrane. Kerosene and crude oil were tested using 5.3 and 7.5 microns membrane at different rotation speed and permeate velocity. Experimental results indicated that in a no blocking condition, the movement of oil drops was determined by shear force and permeate drag force. While in blocking condition, the rejection of oil drops was determined by the formation and characteristic of the secondary membrane formed on the surface of membrane. Blocking will improve the filtration performance in relation to oil rejection, but it will increase the pressure needed or decrease the flux rate through the membrane.