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The green preparation of microporous activated carbon using acorn nutshell with different production conditions was studied. The heating rate and nitrogen flow rate were controlled during preparation. The effect of those conditions on the surface properties and water adsorption performance was observed. According to the results, the total surface area of acorn nutshells-based activated carbon can reach up to 993 m2/g with 90% microporosity and a total pore volume of 0.49 cm3/g. The water adsorption uptake under P/P0 = 0.9 of prepared material is up to 0.39 g/g. This study found that acorn nutshell shows potential performance as a precursor for producing highly microporous activated carbon, which might be suitable for water vapor adsorption.

This study reports a versatile process for the fabrication of a microporous heterogeneous palladium nanocatalyst on a novel spherical, biodegradable, and chemically/physically resistant catalyst support consisting of chitosan (CS) and cigarette waste-derived activated carbon (CAC). The physicochemical properties of the microporous Pd-CS-CAC nanocatalyst developed were successfully determined by FTIR, XRD, FE-SEM, TEM, BET, and EDS techniques. TEM studies showed that the average particle size of the synthesized Pd NPs was about 30 nm. The catalytic prowess of microporous Pd-CS-CAC was evaluated in the reduction/decolorization of various nitroarenes (2-nitroaniline (2-NA), 4-nitroaniline (4-NA), 4-nitrophenol (4-NP), and 4-nitro-o-phenylenediamine (4-NPD)) and organic dyes (methyl red (MR), methyl orange (MO), methylene blue (MB), congo red (CR), and rhodamine B (RhB)) in an aqueous medium in the presence of NaBH4 as the reducing agent at room temperature. The catalytic activities were studied by UV-Vis absorption spectroscopy of the supernatant at regular time intervals. The short reaction times, mild reaction conditions, high efficiency (100% conversion), easy separation, and excellent chemical stability of the catalyst due to its heterogeneity and reusability are the advantages of this method. The results of the tests showed that reduction/decolorization reactions were successfully carried out within 10-140 s due to the good catalytic ability of Pd-CS-CAC. Moreover, Pd-CS-CAC was reused for 5 consecutive times with no loss of the initial shape, size, and morphology, confirming that it was a sustainable and robust nanocatalyst.

To systematically explore the effects of the synthesis conditions on the porosity of hyper-cross-linked polymers (HCPs), a series of 9-phenylcarbazole (9-PCz) HCPs (P1–P11) has been made by changing the molar ratio of cross-linker to monomer, the reaction temperature T1, the used amount of catalyst and the concentration of reactants. Fourier transform infrared spectroscopy was utilized to characterize the structure of the obtained polymers. The TG analysis of the HCPs showed good thermal stability. More importantly, a comparative study on the porosity revealed that: the molar ratio of cross-linker to monomer was the main influence factor of the BET specific surface area. Increasing the reaction temperature T1 or changing the used amount of catalyst could improve the total pore volume greatly but sacrificed a part of the BET specific surface area. Fortunately changing the concentration of reactants could remedy this situation. Slightly changing the concentration of reactants could simultaneously obtain a high surface area and a high total pore volume. The BET specific surface areas of P3 was up to 769 m2 g−1 with narrow pore size distribution and the CO2 adsorption capacity of P11 was up to 52.4 cm3 g−1 (273 K/1.00 bar).

Electric double-layer capacitors (EDLCs) are an excellent electrochemical energy storage system (ESS) because of their superior power density, faster charge–discharge ability, and longer cycle life compared to those of other EES systems. Activated carbons (ACs) have been mainly used as the electrode materials for EDLCs because of their high specific surface area, superior chemical stability, and low cost. Petroleum pitch (PP) is a graphitizable carbon that is a promising precursor for ACs because of its high carbon content, which is obtained as an abundant by-product during the distillation of petroleum. However, the processibility of PP is poor because of its stable structure. In this study, pre-oxidized PP-derived AC (OPP-AC) was prepared to investigate the effects of pre-oxidation on the electrochemical behaviors of PP. The specific surface area and pore size distribution of OPP-AC were lower and narrower, respectively, compared to the textural properties of untreated PP-derived AC (PP-AC). On the other hand, the specific capacitance of OPP-AC was 25% higher than that of PP-AC. These results revealed that pre-oxidation of PP induces a highly developed micropore structure of ACs, resulting in improved electrochemical performance.

This study elucidates a mechanochemical polymerization reaction towards a hyper-crosslinked polymer as an alternative to conventional solvent-based procedures. The swift and solvent-free Friedel–Crafts alkylation reaction yields a porous polymer with surface areas of up to 1720 m2g−1 and pore volumes of up to 1.55 cm3g−1. The application of LAG (liquid-assisted grinding) revealed a profound impact of the liquid´s boiling point on the textural properties of the obtained polymer materials. Finally, the materials are characterized by vapour sorption experiments with benzene and cyclohexane.

Here, we report the design, synthesis, and functional testing of enzyme-powered porous micromotors built from a metal–organic framework (MOF). We began by subjecting a presynthesized microporous UiO-type MOF to ozonolysis, to confer it with mesopores sufficiently large to adsorb and host the enzyme catalase (size: 6–10 nm). We then encapsulated catalase inside the mesopores, observing that they are hosted in those mesopores located at the subsurface of the MOF crystals. In the presence of H2O2 fuel, MOF motors (or MOFtors) exhibit jet-like propulsion enabled by enzymatic generation of oxygen bubbles. Moreover, thanks to their hierarchical pore system, the MOFtors retain sufficient free space for adsorption of additional targeted species, which we validated by testing a MOFtor for removal of rhodamine B during self-propulsion., This work was supported by BIST-IGNITE (MOFtors), the Spanish MINECO (project RTI2018-095622-B-I00), the Catalan AGAUR (project 2017 SGR 238), and the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 866348: iNanoSwarms). It was also funded by the CERCA Program/Generalitat de Catalunya. ICN2 is supported by the Severo Ochoa program from the Spanish MINECO (grant no. SEV-2017-0706). Y.Y. acknowledges the China Scholarship Council for scholarship support. X.A. thanks the Spanish MINECO for the Severo Ochoa program (SEV-2014-0425) for the Ph.D. fellowship (PRE2018-083712). S.S. thanks the Pengcheng Scholar Professorship at Harbin Institute of Technology Shenzhen, China. T.P. thanks the European Union’s Horizon 2020 research and innovation program, under the Marie Skłodowska-Curie Individual Fellowship (H2020-MSCA-IF2018, DNA-bots).

The aim of this work was to fabricate microporous poly(trimethylene carbonate) (PTMC) vascular structures by stereolithography (SLA) for applications in tissue engineering and organ models. Leachable CaCO3 particles with an average size of 0.56 μm were used as porogens. Composites of photocrosslinkable PTMC and CaCO3 particles were cast on glass plates, crosslinked by ultraviolet light treatment and leached in watery HCl solutions. In order to obtain interconnected pore structures, the PTMC/CaCO3 composites had to contain at least 30 vol % CaCO3. Leached PTMC films had porosities ranging from 33% to 71% and a pore size of around 0.5 μm. The mechanical properties of the microporous PTMC films matched with those of natural blood vessels. Resins based on PTMC/CaCO3 composites with 45 vol % CaCO3 particles were formulated and successfully used to build vascular structures of various shapes and sizes by SLA. The intrinsic permeabilities of the microporous PTMC films and vascular structures were at least one order of magnitude higher than reported for the extracellular matrix, indicating no mass transfer limitations in the case of cell seeding.

Raman and FTIR spectroscopy are powerful techniques used to characterize or observe alterations in the structure or properties of Keggin type heteropoly acids, microporous/mesoporous materials, as well as their composites. These methods were applied in this study for investigation of 12-tungstophosphoric acid (WPA) supported as active phase on zeolites (H-BEA and NaY-zeolite) and mesoporous molecular sieves (TiO2, MCM-41, SBA-15). It has been shown that important information on interaction of heteropoly acid and the support can be obtained by the applied vibrational spectroscopic methods. Obtained results show how interaction of WPA with different supports depends on the nature and properties of both, active phase and the support. In the case of microporous supports such as BEA or NaY zeolites, the basicity of the support, i.e., ratio of Si/Al, strongly determines interaction between WPA species and surface of the support. In the case of mesoporous silica supports, WPA is well dispersed over the support without strong interaction. However, TiO2 causes strong and complex interaction with WPA.

Background Fluorescent silica nanoparticles have been extensively utilised in a broad range of biological applications and are facilitated by their predictable, well-understood, flexible chemistry and apparent biocompatibility. The ability to couple various siloxane precursors with fluorescent dyes and to be subsequently incorporated into silica nanoparticles has made it possible to engineer these fluorophores-doped nanomaterials to specific optical requirements in biological experimentation. Consequently, this class of nanomaterial has been used in applications across immunodiagnostics, drug delivery and human-trial bioimaging in cancer research. Main body This review summarises the state-of-the-art of the use of dye-doped silica nanoparticles in bioapplications and firstly accounts for the common nanoparticle synthesis methods, surface modification approaches and different bioconjugation strategies employed to generate biomolecule-coated nanoparticles. The use of dye-doped silica nanoparticles in immunoassays/biosensing, bioimaging and drug delivery is then provided and possible future directions in the field are highlighted. Other non-cancer-related applications involving silica nanoparticles are also briefly discussed. Importantly, the impact of how the protein corona has changed our understanding of NP interactions with biological systems is described, as well as demonstrations of its capacity to be favourably manipulated. Conclusions Dye-doped silica nanoparticles have found success in the immunodiagnostics domain and have also shown promise as bioimaging agents in human clinical trials. Their use in cancer delivery has been restricted to murine models, as has been the case for the vast majority of nanomaterials intended for cancer therapy. This is hampered by the need for more human-like disease models and the lack of standardisation towards assessing nanoparticle toxicity. However, developments in the manipulation of the protein corona have improved the understanding of fundamental bio–nano interactions, and will undoubtedly assist in the translation of silica nanoparticles for disease treatment to the clinic.

Microscale and nanoscale CuO was dispersed in Cu using room temperature high-energy ball milling over time intervals of 5, 30, 60, 120, and 240 min. These samples were then annealed under a reducing atmosphere for 1 h at temperatures of 400, 600, 800 and 1000 °C to create porosity by the reduction of the entrained oxides. Increases in porosity exceeding 40% were achieved using intermediate milling times and annealing temperatures. When considered cumulatively, the most effective processing conditions were a milling time of 30 min and expansion at 800 °C, but variations exist within each sample type. The complex relationship between milling time and annealing temperature is investigated in terms of particle size, morphology and microstructure. The findings indicate that room temperature milling is more efficient at producing porosity than comparable cryogenic methods, and this may enable industrial scaling of the process.

In this work, the ability of benzidine-based microporous polymer network as adsorbent for removal of copper(II) species from aqueous solutions was investigated. The designed benzidine-based adsorbent material (BBAM) with high specific surface area was synthesized using phloroglucinol and benzidine monomers with hydrochloric acid catalyst at 180 degrees C for 3 days followed by freeze-drying process. The porosity character of the material was confirmed by SEM analysis and CO2 adsorption/desorption studies at 0 degrees C. The adsorption efficiency of the BBAM for different metal ions, namely Hg(II), Fe(II), Pb(II), Ni(II), Zn(II) and Cd(II) was experimented, however, a specific sorption behavior against Cu(II) ions was observed. The function of pH and contact time was studied and the highest adsorption capacities for Cu (II) were found as 97% with pH of 4.5 at the end of 300 min. As verified by FTIR and XRD spectral analysis, the sorption mechanism is attributed to the coordination system formed between amino groups in the porous structure and Cu(II) ions. Reusability of the system was also presented by applying six cycles without any significant loss of activity. (C) 2015 Elsevier Ltd. All rights reserved.

International audience; The achievement of hierarchical zeolite templated carbons (ZTCs) is firstly reported through the use of mesoporous zeolites as sacrificial scaffolds. The achieved hierarchical ZTCs feature both tailored microporosity and high degree of mesoporosity and allow hence to bridge the gap between classical ZTCs and CMK-like materials. Mesoporosity from steamed zeolites was meticulously transcribed to the ZTC particles. The use of zeolites featuring surfactant-templated mesoporosity allowed for achieving a ZTC with a very high mesopore volume (0.85 cm 3 g −1). The rearrangement of surfactant-templated mesoporosity could be evidenced through nitrogen physisorption and transmission electron microscopy on ultramicrotomed samples. The rearrangement of mesoporosity during ZTC formation has been found to impact coherent crystal size and the lattice strain of the zeolite template. The combination of data from X-ray diffraction and nitrogen physisorption allowed further to reveal that the thickness of the ZTC skeleton is impacted by the degree of intracrystalline mesoporosity in the template zeolite. Through comparing the textural characteristics of the zeolite templates and of the achieved hierarchical ZTCs, important evidence was found that the surfactant-templating of USY zeolite leads to the development of a secondary amorphous phase and that the reduction of the microporous volume during this process is merely apparent.

In this study, reactive crystallisation is introduced into a liquid-liquid membrane contactor for the selective separation, purification and recovery of ammonia from concentrated waste. Whilst liquid-liquid membrane contactor technology has been previously demonstrated for ammonia absorption, further process intensification can be achieved by incorporating crystallisation into transmembrane chemisorption to recover the ammonia as crystalline ammonium sulphate. Reactive crystallisation occurred in the draw solution (sulphuric acid) which was supplied to the lumen-side of the polypropylene hollow-fibre. The ammonium sulphate concentration in the draw solution increased through ammonia mass transfer to supersaturation, at which time induction (the onset of nucleation) commenced. Ammonia mass transfer at draw concentrations above the solubility limit was not limited provided sufficient ‘free’ sulphate was available. This resulted in nucleation which occurred at a low level of supersaturation (C/C*, 1.03) to produce small crystals of around 2.5 μm, which indicated that nucleation was favoured. The nucleation rate was found to be proportional to the ammonia flux in the draw solution. As the solution became more saturated, crystal number increased but crystal growth was comparatively small; this is symptomatic of reactive crystallisation, where the rate of reaction exceeds the rate of mass transfer. Due to the large difference in the ratio between the lumen internal diameter and the mean crystal diameter ( d f i b r e / d m e a n , C S D , ~180), no fibre clogging was observed despite facilitating crystallisation on the lumen-side of the membrane. Transmembrane chemisorption crystallisation presents a feasible process intensification for the selective separation of ammonia from environmental applications. For its integration into environmental applications, solutions to wetting and fouling remain due to associative interactions with the complex organic matrix that are practically achievable through engineering intervention. Subsequent transformation of ammonia into a crystalline phase of ammonium sulphate presents a new product which is of commercial interest.

The article recently published in Electrochim. Acta [1] reported the results obtained by us about three main items: 1. The stability voltage window and working voltage window for the electrolytes Et4NBF4, Pr4NBF4 and Bu4NBF4 in combination with a microporous carbon monolith (Micro CM) and also with a mesoporous carbon monolith (Meso CM). 2. The specific capacitance associated with the anion BF4 - and the three cations Et4Nþ, Pr4Nþ and Bu4Nþ and their relative contributions to the total specific capacitance, the latter as measured in the three-electrode cell and the two-electrode one. 3. The comparison of the ratios of the specific capacitances of the anion and the three cations and the ratios of the surface areas deduced for pores with sizes larger than certain values, the latter ratio obtained from immersion calorimetry (for micro CM) and N2 adsorption isotherm/HS-2D-NLDFT (for meso CM). I think that the agreement between the ratios of the specific capacitances and the ratios of the surface areas pointed out the validity of the two techniques (immersion calorimetry and adsorption isotherms) for determining relative values of the surface areas. Moreover, the comparison of the capacitance ratios with the surface areas ratios allowed us the estimation of the minimum size of pore able to host the anion and the three cations as they are electro-adsorbed at the electric double layer. Because we were aware that different techniques for measuring the specific surface areas can lead to different values, only the last paragraph of the Results and Discussion section (page 128) dealt with the item of capacitance normalized by surface area, i.e. the capacitance normalized by the absolute values of the surface areas. The comments by T.A. Centeno points out that the surface areas obtained by immersion calorimetry can differ from the surface areas deduced from DFT on adsorption isotherms of CO2 and N2.We also observed that the surface areas deduced by HS-2D-NLDFT agreed better with the experimental adsorbed volumes than the values deduced from NLDFT, although the two soft-wares (HS-2DNLDFT and NLDFT) were applied on the same N2 adsorption isotherm and were provided by the same company. I think that the comments by T.A. Centeno raise the question: which is the technique/procedure suitable for analyzing the real surface area? The immersion calorimetry technique seems to be affected by ¿gate¿ restrictions in addition to a limited number of molecule sizes for analyzing the complete microporous range, up to 2 nm. The adsorption techniques provide direct and real values of adsorbed volumes but questionable values of surface areas. I have discussed about these matters with researchers who investigated on textural properties of carbons. Some of them said that the surface areas deduced from the different techniques/procedures are actually ¿apparent¿ surface areas. So, they proposed to use the surface areas only in a comparative manner, e.g. for measuring variations (or ratios) after increasing or decreasing porosity.

This contribution reports the preparation of electrospun lignin-based carbon fibers at different carbonization temperatures and the influence of heat treatments at temperatures ranging from 900 to 1600 ºC. The influence of the addition of phosphoric acid in the initial electrospinning solution on the structural ordering, electrical conductivity and porosity development of the final carbon fibers is studied in detail. Alcell lignin fibers were electrospun using a coaxial electrospinning device following the procedure previously reported by our research group. Electrospun H3PO4-lignin fibers were prepared in the same device by addition of phosphoric acid to the lignin solution using mass ratios of 0.1 and 0.3. The electrospun fibers were stabilized in air at 200 ºC, using a slow heating rate and carbonized under inert atmosphere at temperatures between 500 and 900 ºC. In addition, the fibers carbonized at 900 ºC were heat treated at temperatures between 1200 and 1600 ºC. The high temperature heat treatment removes most of the heteroatoms (O, P) for both carbon fibers. However, the surface area of the phosphorous containing carbon fibers is mostly preserved after the heat treatment, while a large porosity shrinkage is observed for the pure lignin-derived fibers. Thus, microporous carbon fibers with large electrical conductivity values have been obtained by heat treatment at 1600 ºC of P-containing electrospun carbon fibers. Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech.

Two types of silica particles were synthesized by the sol-gel process. The first type of silica particles was synthesized by neutralization of a highly basic sodium silicate solution. The obtained particles were polydispersed with irregular shapes and a mesoporous structure. The second type of silica particles was prepared by hydrolysis and condensation of tetraethylortosilicate (TEOS). The obtained particles were spherical and monodispersed with a microporous structure. Multimodal size distribution was characteristic of the silica particles obtained from the sodium silicate solution with a particle size distribution between 0.2 and 6 μm. On the other hand, the silica particles obtained from TEOS had a unimodal size distribution with an average particle size of about 0.5 μm. The physical adsorption of Candida rugosa lipase onto the obtained silica particles was investigated at pH=7. The silica particles prepared from TEOS had the lowest adsorption efficiency (2%) while those prepared from the highly basic sodium silicate solution had the highest adsorption efficiency (50%). The isoelectric point of silica particles and Candida rugosa lipase was 2.5 and 2.4, respectively, which suggests that van der Waals' forces probably play the major role in the process of binding lipase into mesoporous silica when physical adsorption was involved at pH 7.

Porous solid sorbents have been investigated for the last few decades to replace the costly amine solution and explore the most efficient and economical material for CO2 capture and storage. Covalent organic polymers (COPs) have been recently introduced as promising materials to overcome several issues associated with the solid sorbents such as thermal stability and low gas capturing capacity. Herein we report the synthesis of four COPs and their CO2, N2 and CH4 uptakes. All the presented COP materials were characterized by using an elemental analysis method, Fourier transform infrared spectroscopy (FTIR) and solid state nuclear magnetic resonance (NMR) spectroscopy techniques. The physical properties of the materials such as surface area, pore volume and pore size were determined by BET analysis at 77 K. All the materials were tested for CO2, CH4 and N2 adsorption through a volumetric method using magnetic sorption apparatus (MSA). Among the presented materials, COP-118 has the highest surface area of 473 m2 g-1 among the other four materials and has shown excellent performance by capturing 2.72 mmol g-1 of CO2, 1.002 mmol g-1 of CH4 and only 0.56 mmol g-1 of N2 at 298 K and 10 bars. However the selectivity of another material, COP-117-A, was better than that of COP-118. Nevertheless, the overall performance of the latter has indicated that this material can be considered for further exploration as an efficient and cheaply available solid sorbent compound for CO2 capture and separation. 2016 The Royal Society of Chemistry. Scopus

Cell-encapsulating devices can play an important role in advancing the types of tissue available for transplantation and further improving transplant success rates. To have an effective device, encapsulated cells must remain viable, respond to external stimulus, and be protected from immune responses, and the device itself must elicit a minimal foreign body response. To address these challenges, we developed a micro- and a nanoporous thin-film cell encapsulation device from polycaprolactone (PCL), a material previously used in FDA-approved biomedical devices. The thin-film device construct allows long-term bioluminescent transfer imaging, which can be used for monitoring cell viability and device tracking. The ability to tune the microporous and nanoporous membrane allows selective protection from immune cell invasion and cytokine-mediated cell death in vitro, all while maintaining typical cell function, as demonstrated by encapsulated cells' insulin production in response to glucose stimulation. To demonstrate the ability to track, visualize, and monitor the viability of cells encapsulated in implanted thin-film devices, we encapsulated and implanted luciferase-positive MIN6 cells in allogeneic mouse models for up to 90 days. Lack of foreign body response in combination with rapid neovascularization around the device shows promise in using this technology for cell encapsulation. These devices can help elucidate the metrics required for cell encapsulation success and direct future immune-isolation therapies.

Composite microporous SiO2-TiO2 spheres and micro/mesoporous TiO2 spheres were prepared via the template-free two-step synthetic route using aqueous peroxotitanate solution and tetraethyl orthosilicate (TEOS) as precursors. Both the composite SiO2-TiO2 and pure TiO2 spheres prepared by the solvent-exchange method were initially non-porous, but the applied reflux treatment in water-ethanol suspension successfully transformed them into microporous materials with high apparent surface areas approaching 500 m2·g− 1 and the micropore volume of 0.17 cm3·g− 1, while maintaining the same morphology. The prepared composites retained high values of pore volume and specific surface area up to 400 °C of thermal treatment temperature. The crystallization of TiO2 into the anatase phase in the mixed oxide occurred only at 700 °C, that process was also accompanied by the significant reduction of pore volume, as well as apparent surface area values. The prepared materials were tested as adsorbents for the lead(II) removal; they demonstrated high adsorption capacities, reaching 340 mg(Pb2 +)·g− 1. Moreover, the mixed silica-titania oxide was found to be more efficient adsorbent at low pH values., South Ural State University is grateful forfinancial support of theMinistry of Education and Science of the Russian Federation (grant No16.2674.2014/K). University of Oviedo gratefully acknowledgesfi-nancial support from the Spanish MINECO (MAT2013-40950-R andMAT2016-78155-C2-1-R). Igor Krivtsov thanks for the support theRussian Foundation for Basic Research 16-29-10757-ofi.

The dissolution of microporous silica nanoparticles (NP) in aqueous environments of different biologically relevant pH was studied in order to assess their potential as drug delivery vehicles. Silica NPs, loaded with fluorescein, were prepared using different organosilane precursors (tetraethoxysilane, ethyl triethoxysilane or a 1:1 molar ratio of both) and NP dissolution was evaluated in aqueous conditions at pH 4, pH 6 and pH 7.4. These conditions correspond to the acidity of the intracellular environment (late endosome, early endosome, cytosol respectively) and gastrointestinal tract (‘fed’ stomach, duodenum and jejunum respectively). All NPs degraded at pH 6 and pH 7.4, while no dissolution was observed at pH 4. NP dissolution could be clearly visualised as mesoporous hollows and surface defects using electron microscopy, and was supported by UV–vis, fluorimetry and DLS data. The dissolution profiles of the NPs are particularly suited to the requirements of oral drug delivery, whereby NPs must resist degradation in the harsh acidic conditions of the stomach (pH 4), but dissolve and release their cargo in the small intestine (pH 6–7.4). Particle cores made solely of ethyl triethoxysilane exhibited a ‘burst release’ of encapsulated fluorescein at pH 6 and pH 7.4, whereas NPs synthesised with tetraethoxysilane released fluorescein in a more sustained fashion. Thus, by varying the organosilane precursor used in NP formation, it is possible to modify particle dissolution rates and tune the release profile of encapsulated fluorescein. The flexible synthesis afforded by silica NPs to achieve pH-responsive dissolution therefore makes this class of nanomaterial an adaptable platform that may be well suited to oral delivery applications.

Mesoporous silica nanoparticles (MSNs) have sparked considerable interest in drug/gene delivery, catalysis, adsorption, separation, sensing, antireflection coatings and bioimaging because of their tunable structural properties. The shape, size and pore structure of MSNs are greatly influenced by the type of additives used, e.g., solvent and pore-templating agent. Here, we studied the influence of cyclodextrin (CD) molecules on the formation of MSNs. The nanoparticles over 100 nm in diameter were synthesized by surfactant-templated, hydrolysis–polycondensation reactions in the presence of pristine CD (β-CD) or hydroxypropyl-functionalized CDs (HP-γ-CD and HP-β-CD). Depending on the formulation conditions, differently shaped MSNs, such as bean-like, spherical, ellipsoid, aggregate and faceted were generated. The morphology and size of MSNs varied with the CD-type used. Generally, spherical particles were obtained with β-CD, while a faceted morphology was observed for the particles synthesized using HP-CDs. The particle size could be tuned by adjusting the amount of CD used; increasing the CD concentration led to larger particles. MSNs synthesized in the presence of β-CD displayed a smaller particle size than those produced with HP-functional CDs. FTIR, TGA and solid-state 13C NMR demonstrated the adsorption of CDs on the particle surfaces. The proposed concept allows for the synthesis of silica nanoparticles with control over particle shape and size by adjusting the concentration of additives in a simple, one-pot reaction system for a wide range of applications.

Acoustic manipulation of porous spherical shells, widely used as drug delivery carriers and magnetic resonance imaging contrast agents, is investigated analytically. The technique used for this purpose is based on the application of high-order Bessel beams as a single-beam acoustic manipulation device, by which particles lying on the axis of the beam can be pulled toward the beam source. The exerted acoustic radiation force is calculated using the standard partial-wave series method, and the wave propagation within the porous media is modeled using Biot's theory of poro-elasticity. Numerical simulations are performed for porous aluminum and silica shells of different thickness and porosity. Results indicate that manipulation of low-porosity shells is possible using Bessel beams with large conical angles, over a number of broadband frequency ranges, whereas manipulation of highly porous shells can occur over both narrowband and broadband frequency domains.

Microporous membranes are widely utilized in cell biology to study cell–cell signaling and cell migration. However, the thickness and low porosity of commercial track-etched membranes limit the quality of cell imaging and the degree of cell–cell contact that can be achieved on such devices. We employ photolithography-based microfabrication to achieve porous membranes with pore diameter as small as 0.9 µm, up to 40% porosity, and less than 5% variation in pore size. Through the use of a soap release layer, membranes as thin as 1 µm can be achieved. The thin membranes minimally disrupt contrast enhancement optics, thus allowing good quality imaging of unlabeled cells under white light, unlike commercial membranes. In addition, the polymer membrane materials display low autofluorescence even after patterning, facilitating high quality fluorescence microscopy. Finally, confocal imaging suggests that substantial cell–cell contact is possible through the pores of these thin membranes. This membrane technology can enhance existing uses of porous membranes in cell biology as well as enable new types of experiments.

The hybrid metal-organic frameworks (MOFs) with different Zn2+/Co2+ ratios are synthesized at room temperature with deionized water as the solvent. This use of deionized water can increase the yield of hybrid MOFs (up to 65&ndash, 70%). After the pyrolysis, the obtained nanoporous carbons (NPCs) show a decrease in the surface area, in which the highest surface area is 655 m2 g&minus, 1. The as-prepared NPCs are subjected to activation with KOH in order to increase their surface area and convert cobalt nanoparticles (Co NPs) to Co oxides. These activated carbons are applied to electrical double-layer capacitors (EDLCs) and pseudocapacitors due to the presence of CoO and Co3O4 nanoparticles in the carbon framework, leading to significantly enhanced specific capacitance as compared to that of pristine NPCs. This synthetic method can be utilized in future research to enhance pseudocapacitance further while maintaining the maximum surface area of the carbon materials.

Treatment of defects in joint cartilage aims to re-establish normal joint function. In vitro experiments have shown that the application of synthetic scaffolds is a promising alternative to existing therapeutic options. A sheep study was conducted to test the suitability of microporous pure beta-tricalcium phosphate (TCP) ceramics as tissue engineering scaffolds for the repair of osteochondral defects. Cylindrical plugs of microporous beta-TCP (diameter: 7 mm; length: 25 mm; porosity: 43.5 ± 2.4%; pore diameter: about 5 µm) with interconnecting pores were used. Scaffolds were seeded with autologous chondrocytes in vitro and cultured for 4 weeks. A drill hole (diameter 7 mm) was placed in both medial femoral condyles of sheep. For the left knee the defect was filled with a TCP plug and for the right knee the defect was left empty. After 6, 12, 26 and 52 weeks, seven animals from each group were killed and studied. The samples were examined employing histological, histomorphometric and immunohistological methods as well as various imaging techniques (X-ray, microcomputer tomography and scanning electron microscopy). After explantation the cartilage defects were first assessed macroscopically. There were no signs of infection or inflammation. Histological grading scales were used for assessment of bony integration and cartilage repair. An increasing degradation (81% after 52 weeks) of the ceramic with concomitant bone formation was observed. The original structure of cancellous bone was almost completely restored. After 26 and 52 weeks, collagen II-positive hyaline cartilage was detected in several samples. New subchondral bone had formed. The formation of cartilage began at the outer edge and proceeded to the middle. According to the O'Driscoll score, values corresponding to healthy cartilage were not reached after 1 year. Integration of the newly formed cartilage tissue into the surrounding native cartilage was found. The formation of biomechanical stable cartilage began at the edge and progressed towards the centre of the defect. After 1 year this process was still not completed. Microporous beta-TCP scaffolds seeded with chondrocytes are suitable for the treatment of osteochondral defects.

The adsorption of Cs+ by clay minerals is a complicate process, being cation exchange and frayed-edge sites the major mechanisms that govern it. However, environmental variables have a significant impact on the process. In this work, the influence of the temperature and time in the cesium adsorption capacity of Na-Mica-n (n=2 and 4) have been explored under subcritical conditions. Those synthetic micas were able to immobilize cations Cs+ combining adsorption at nonspecific sites, at specific sites and chemical reaction. The distribution constant of Cs+ was larger in the Na-Mica-2 denoting a higher concentration of specific adsorption sites when layer charge decreased.

Carbon foams displaying hierarchical porosity and excellent surface areas of >1400 m2/g can be produced by the activation of macroporous poly(divinylbenzene). Poly(divinylbenzene) was synthesized from the polymerization of the continuous, but minority, phase of a simple high internal phase Pickering emulsion. By the addition of KOH, chemical activation of the materials is induced during carbonization, producing Pickering-emulsion-templated carbon foams, or carboHIPEs, with tailorable macropore diameters and surface areas almost triple that of those previously reported. The retention of the customizable, macroporous open-cell structure of the poly(divinylbenzene) precursor and the production of a large degree of microporosity during activation leads to tailorable carboHIPEs with excellent surface areas.

[EN] Porous sulphur-doped carbons have been prepared by using polythiophene (PTh) as carbon precursor and KOH as activating agent. The activation process was carried out under several operating conditions, i.e. a KOH/PTh weight ratio of 2 or 4 and reaction temperatures in the 600–850 °C range. The porous carbons thus obtained exhibit very large apparent surface areas and high pore volumes of up to 3000 m2 g−1 and 1.75 cm3 g−1 respectively for a sample prepared at 850 °C and with a KOH/PTh weight ratio = 2. The pore size distribution of these carbons gradually changes with the reaction temperature. Thus, whereas the porosity of the samples prepared at 600 °C is mostly formed by micropores ∼1 nm, those obtained at 850 °C exhibit two pore systems with diameters of ∼1 nm and ∼2.5 nm. These polythiophene-based porous carbons have large sulphur contents in the 3–12 wt% range, and this percentage decreases as the reaction temperature rises. The sulphur present in these carbons forms two types of functional groups (i.e. sulphide –C–S–C– and sulphone –C–SO2–C–) which act as bridges between adjacent aromatic rings., The financial support for this research work provided by the Spanish MCyT (MAT2008-00407) is gratefully acknowledged. M. S. thanks the Spanish MCyT for the award of a Postdoctoral Mobility contract.

Lipase enzyme from Aspergillus oryzae (EC 3.1.1.3) was immobilized onto a micro porous polymeric matrix which contains aldehyde functional groups and methyl esters of long chain fatty acids (biodiesel) were synthesized by transesterification of crude canola oil using immobilized lipase. Micro porous polymeric matrix was synthesized from styrene divinylbenzene (STY-DVB) copolymers by using high internal phase emulsion technique and two different lipases, Lipozyme TL-100L (R) and Novozym 388 (R), were used for immobilization by both physical adsorption and covalent attachment. Biodiesel production was carried out with semi-continuous operation. Methanol was added into the reactor by three successive additions of 1:4 M equivalent of methanol to avoid enzyme inhibition. The transesterification reaction conditions were as follows: oil/alcohol molar ratio 1:4; temperature 40 degrees C and total reaction time 6 h. Lipozyme TL-100L (R) lipase provided the highest yield of fatty acid methyl esters as 92%. Operational stability was determined with immobilized lipase and it indicated that a small enzyme deactivation occurred after used repeatedly for 10 consecutive batches with each of 24 h. Since the process is yet effective and enzyme does not leak out from the polymer, the method can be proposed for industrial applications. (C) 2010 Elsevier Ltd. All rights reserved.

The esterification of free fatty acids (FFA) is an alternative for the production of biodiesel from oils with high concentrations of FFA. In this paper, catalysts for the esterification of oleic acid with methanol were prepared from two Amazon kaolins (Century and flint ) and two standard kaolins (KGa-1b and KGa-2) that were thermally treated at 950 °C and leached with 4 M sulfuric acid solutions. The activated metakaolin samples were characterized by X-ray diffraction, scanning electron microscopy, N 2 adsorption–desorption and pyridine adsorption studies using TG/DTG and FTIR analysis. The leached metakaolin prepared from Century showed the lowest Al content, the highest number of acidic sites (250.5 μmolPy/g) and offered larger conversion values. The influences of reaction parameters, such as temperature and time, were also investigated. Based on the catalytic results, kaolin was found to be a promising raw material for the production of new solid acid catalysts for the esterification of FFA. In particular, Amazonian flint kaolin, previously considered unusable for biofuel, was found to be amenable to production.

The esterification of free fatty acids (FFA) can be used to produce biodiesel from high FFA oils. In this work, a new eco-friendly catalyst for the esterification of oleic acid with methanol has been prepared from a waste material, Amazon flint kaolin, that was thermally treated (at 850 and 950 °C) and activated with sulfuric acid solutions (1 M and 4 M). The activated metakaolin samples were characterized by X-ray diffraction, scanning electron microscopy, N 2 adsorption–desorption and adsorption studies of pyridine using TG/DTG and FTIR analysis. The leached metakaolin treated at 950 °C and activated with 4 M sulfuric acid solution showed the highest surface area (406 m 2 /g), the highest number of acid sites (237.7 μmol/g) and offered the maximum esterification activity (98.9%) at 160 °C, an acid:methanol molar ratio of 1:60 and 4 h reaction time. The influences of reaction parameters such as the molar ratio of the reactants, alcohol chain length, temperature and time have also been investigated. Based on the catalytic results, Amazon flint kaolin is found to be a promising raw material for the production of new solid acid catalysts for the esterification of FFAs.

Microbial lipase from Thermomyces lanuginosus (formerly Humicola lanuginosa ) was immobilized by covalent binding on a novel microporous styrene–divinylbenzene polyglutaraldehyde copolymer (STY–DVB–PGA). The response surface methodology (RSM) was used to optimize the conditions for the maximum activity and to understand the significance and interaction of the factors affecting the specific activity of immobilized lipase. The central composite design was employed to evaluate the effects of enzyme concentration (4–16%, v/v), pH (6.0–8.0), buffer concentration (20–100 mM) and immobilization time (8–40 h) on the specific activity. The results indicated that enzyme concentration, pH and buffer concentration were the significant factors on the specific activity of immobilized lipase and quadratic polynomial equation was obtained for specific activity. The predicted specific activity was 8.78 μmol p -NP/mg enzyme min under the optimal conditions and the subsequent verification experiment with the specific activity of 8.41 μmol p -NP/mg enzyme min confirmed the validity of the predicted model. The lipase loading capacity was obtained as 5.71 mg/g support at the optimum conditions. Operational stability was determined with immobilized lipase and it indicated that a small enzyme deactivation (12%) occurred after being used repeatedly for 10 consecutive batches with each of 24 h. The effect of methanol and tert -butanol on the specific activity of immobilized lipase was investigated. The immobilized lipase was almost stable in tert -butanol (92%) whereas it lost most of its activity in methanol (80%) after 15 min incubation.

In a decade, many porous coordination polymers have been synthesized, providing a variety of properties ranging from storage, separation and exchange of guests in their cavities, magnetism, conductivity and catalysis by their frameworks. Recent advent of flexible porous coordination polymers, which exhibit elastic guest accommodation in contrast to rigid three-dimensional (3-D) frameworks of conventional porous materials, have acquired a position as a new class of porous materials. Such flexible porous properties induce highly selective guest accommodation and magnetic modulation, which could now be a unique class of practical materials. In this review, we introduce recent flexible porous coordination polymers (3–17) and their functional properties, categorizing with the four types of pores with framework deformation.

[EN] Synthesis of S-doped activated carbons (ACs) by carbonization and simultaneous activation of S-based polymers was found to be an efficient route to produce porous carbons for double layer capacitors (EDLCs) with high specific energy and power densities combined with low self-discharge. Here we investigate for the first time the processing-structure–property relationships related to the formation of polythiophene-derived ACs for EDLC applications. Sulfide bridges present in the polymer precursor were found to depress the shrinkage of the smallest micropores during the carbonization process and allow for the enhanced ion transport within the produced AC electrodes. The cyclic voltammetry (CV) measurements on S-doped ACs produced at 800 and 850 °C showed high specific capacitance (up to [similar]200 F g−1) and no significant self-discharge in neutral aqueous electrolytes. More importantly, these capacitance values remained virtually identical for a sweep rate increasing from 1 to 50 mV s−1. The observed capacitance retention is quite remarkable for thick electrodes of [similar]200 μm and a large AC particle size of 10–100 μm. It indicates great potential of the proposed synthesis technology for EDLCs operating at high frequencies and high currents. In the course of our systematic studies of AC performance in different electrolytes we found a strong correlation between the large pseudocapacitance and the significant self-discharge in ACs. We harness the difference between the characteristic times required to establish a double layer and that of the pseudocapacitive redox reactions and propose a simple method to estimate the fraction of pseudocapacitance. The proposed method is particularly valuable in cases when CV measurements do not show clear characteristic reduction–oxidation peaks., The financial support for this research work provided by the US Army Research Office (grant W911NF-12-1-0259), by the Spanish MINECO (CQT2011-24776 and MAT2012-31651) and by the Energy Efficiency & Resources program of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) funded by the Korea government Ministry of Knowledge Economy (grant 20118510010030) is gratefully acknowledged. M. S. thanks the Spanish MINECO for the award of a Ramón y Cajal contract.

Kanemite belongs to the group of naturally occurring sodium silicate minerals that was first found in Kanem, at the edge of the Lake Chad, and has been synthesized in different ways from NaOH-SiO2 mixtures and used as precursor for the design of microporous and mesoporous materials. The fluoride route to the synthesis of microporous materials is based on the substitution of OH− anions by fluoride anions, which may subsequently also play a mineralizing role, and gives rise to materials with higher hydrophobicity and thermal and hydrothermal stability. Moreover, F− plays an important role in the incorporation of framework heteroatoms, thereby affecting the activity of the final material. The aim of this study was to synthesize fluorokanemite using different synthetic routes and different F− source. The final product was characterized by a combination of methods that provided information regarding the incorporation of fluorine into the framework and the short- and long-range structural order of the fluorosilicate. Kanemite with water content close to ideal was obtained in all cases. The washing process was found to have no effect in the long- or short-range structural order of the layer framework, although it did affect the structure of the cation in the interlayer space of kanemite. The mineralizing agent therefore appears to be the key to the synthesis. Furthermore, it governs the resulting kanemite structure by controlling the formation of hydrogen bonds in the framework, and therefore the degree of lamellar structure condensation.

The formation is described of supported microporous membranes (by IUPAC definition rpore < 1 nm), prepared by modification of mesoporous γ-alumina membranes with polymeric sols. The mesoporous γ-alumina membranes, with a top-layer thickness in the order of 7–10 μm, and with pore radii of 2–2.5 nm, have a very high surface finish (mean roughness 40 nm). The amorphous microporous top-layer thickness is in the order of 60–100 nm. Gas transport properties are effectively improved as is shown by activated permeation and molecular sieve-like separation factors in the order of 50–200 for H2/CH4. These microporous top-layers can be prepared from a relatively wide range of sol structures; from inorganic oligomers which are too small to result in significant scattering with SAXS, to polymeric structures with fractal dimensions in the range: 1

Different types of titanosilicates are synthesized, structurally characterized, and subsequently catalytically tested in the liquid-phase epoxidation of cyclohexene. The performance of three types of combined zeolitic/mesoporous materials is compared with that of widely studied Ti-grafted-MCM-41 molecular sieve and the TS-1 microporous titanosilicate. The catalytic test results are correlated with the structural characteristics of the different catalysts. Moreover, for the first time, immersion calorimetry with the same substrate molecule as in the catalytic test reaction is applied as an extra means to interpret the catalytic results. A good correlation between catalytic performance and immersion calorimetry results is found. This work points out that the combination of catalytic testing and immersion calorimetry can lead to important insights into the influence of the materials structural characteristics on catalysis. Moreover, the potential of using immersion calorimetry as a screening tool for catalysts in epoxidation reactions is shown.

A lanthanide-based metal organic framework, formulated Tb(C27H15O6)(H2O)·2C6H11OH, has been solvothermally synthesized using the extended rigid tritopic ligand 1,3,5-tribenzoate. Included free solvent could be removed upon heating, and the resulting material presents large 1-D micropores (free diameter = 10 A) and a high surface area (SLangmuir > 1000 m2·g-1).