Impregnation Of Carbon Research Articles

High conversion of xylose to furfural over corncob residue-based solid acid catalyst in water-methyl isobutyl ketone

In order to improve the high-value utilization of raw materials in furfural production, a solid acid catalyst based on corncob residue (S-IRCC) was synthesized using the method of impregnation–carbonization–sulfonation. The impregnation of FeCl3 makes S-IRCC exhibit excellent surface area and catalytic activity, and S-IRCC possessing -COOH, phenolic -OH, and -SO3H groups. The effects of reaction conditions on furfural yield, xylose concentration, and furfural selectivity were investigated. It was found that the addition of NaCl would improve furfural yield in water- methyl isobutyl ketone system. Optimal furfural yield (73.64%) and selectivity (74.2%) were obtained for 1:1 xylose/catalyst ratio (w/w) at 190 °C for 60 min in 1:2 water–methyl isobutyl ketone (v/v) with 60 g/L NaCl. In addition, with the regeneration, the catalyst activity is easily restored to its original level. Hence, bio-carbon-based catalyst shows potential application value in furfural production and biomass utilization.

Fe3+-assistantly carbon-impregnated porous SiO2 mesoscale tubes as Li-ion battery anode materials with highly enhanced performances

Porous SiO 2 mesoscale tubes (SiO 2 -pMT) impregnated with carbon in the pores within their tube walls were successfully prepared for the first time by making use of the Fe 3+ assisted anchoring of dopamine (DA) on the surface of SiO 2 as carbon source, and thereby endowed with highly enhanced anode performances for Li-ion batteries. Typically, a reversible specific capacity of 512.8 mAh g −1 was achieved after 500 cycles at 1 A g −1 when the SiO 2 -pMT impregnated with carbon by Fe 3+ assistance was used as anode material, which is about 10 times that of SiO 2 -pMT with no carbon impregnation and 25% higher than that of the SiO 2 -pMT with carbon impregnated at double the concentration of dopamine but in the absence of Fe 3+ cations. It has been found that the carbon impregnation of the SiO 2 -pMT may be achieved more easily and homogeneously with the assistance of Fe 3+ cations and, as a result, 3-dimensional porous carbon-networks with higher connectivity can be built up, which greatly facilitate the transport of electrons to more potential reaction sites where Li-ions are available and provide fast channel for Li-ions diffusion, leading to enhanced electrochemical kinetics, as unveiled by the differential capacity curves and electrochemical impedance spectra acquired at different intervals during the initial cycle. Furthermore, as shown by XPS data, such benefitial assistance of Fe 3+ cations is believed to arise from their coupling effects between the phenolic hydroxyl groups of dopamine molecules and the surface of SiO 2 through the chemical bondings of C-O-Fe and Fe-O-Si. Fe 3+ -assisted carbon impregnation of porous SiO 2 mesoscale tubes (SiO 2 -pMT) with dopamine as carbon source (via path 1) leading to remarkable enhancement in carbon content, structural homogeneity, and anode performance in Li-ion battery in contrast to that achieved with no Fe 3+ -assistance (via path 2). • Fe 3+ was firstly introduced into dopamine for the fabrication of SiO 2 -pMT@iC. • The carbon impregnation was achieved more homogeneously with the assistance of Fe 3+ . • The coupling effect of Fe 3+ exists through the chemical bonds of C-O-Fe and Fe-O-Si. • High connected porous carbon network enable SiO 2 -pMT@iC with enhanced performance.

Carbon-Carbon Composite Materials Based on Low Modulus Fabrics

Scientific research and the search for new technologies to increase the level of mechanical and high-temperature properties are ongoing. The article discusses the technology of using carbon materials, pyrolysis and impregnation with phenol-formaldehyde resins. It is shown that the proposed technology makes it possible to achieve a sufficient level of mechanical properties when using low-modulus carbon fabrics after pyrolytic treatment as a prepreg at a temperature treatment no higher than 900 K. Pillowcase and resole phenol-formaldehyde resins were used to impregnate the prepreg. The proposed technology also allows the introduction of alloying additives into the system to improve the properties. An example of the introduction of nitrogen into a composite by adding urotropine to a phenol-formaldehyde resin, which was used to impregnate the composite, is considered.

Ambient Electrochemical Nitrogen Fixation over a Bifunctional Mo–(O–C2)4 Site Catalyst

The electrochemical synthesis of NH3 and NO3– by the N2 reduction reaction (NRR) and the N2 oxidation reaction (NOR) under ambient conditions utilizing H2O as the hydrogen and oxygen source has aroused great attention. Here, we report the fabrication of oxygen-coordinated molybdenum (Mo) single atoms anchored on carbon (Mo–O–C) using bacterial cellulose (BC) as the impregnation regulator and carbon source. As a result, the as-synthesized Mo–O–C as an electrocatalyst exhibits superior bifunctional NRR and NOR activities with high stability. A superb NH3 yield rate of 248.6 ± 12.9 μg h–1 mgcat.–1 and a faradaic efficiency (FE) of 43.8 ± 2.3% can be obtained at −0.20 V (vs RHE) by the Mo–O–C-catalyzed NRR, and Mo–O–C can also afford a NO3– yield rate of 217.1 ± 13.5 μg h–1 mgcat.–1 with a FE of 7.8 ± 0.5% at 2.35 V (vs RHE) for the NOR. The synchrotron-based X-ray absorption spectra and theoretical calculation results unveil that the O-coordinated molybdenum configuration of Mo–(O–C2)4 anchored on carbon is the most stable single-atom structure as the catalytic active sites for N2 adsorption, activation, and bifunctional hydrogenation/oxidation reactions.

Синтез и исследование никель-алюминиевых оксидных катализаторов на углеродном носителе

Activated carbons, which have a highly developed specific surface area and large pore sizes, have recently been increasingly considered as economically available carriers of catalytic systems for deep processing of heavy hydrocarbon feedstock. In this work, samples of catalysts obtained by impregnation of active carbon with oxides of NiO and Al2O3 were studied. It is shown that an increase in the ratio of metal cations Ni/Al in the impregnating solution from 2:1 to 3:1 leads to a decrease in the average pore diameter and an increase in the specific surface area of activated carbon by 1.5 times. Activated carbons impregnated with Ni/Al metal oxides with a ratio of metal cations in an impregnating solution of 3:1, calcined in a stream of hydrogen, have the largest pore area with a diameter of 10–200 nm. Heat treatment of Ni-Al oxide catalysts on a carbon carrier at a temperature of 450°С in a hydrogen flow leads to an increase in the pore size and a decrease in the specific surface area. Mechanical activation of oxide catalysts on a carbon carrier by ultrasonic action increases the area of the outer surface of the particles by more than two times.

Catalytic performance improved by catalyst‐integration technology and boostingH2Scatalytic adsorption

Herein, impregnation is a traditional and normal method to load catalyst on the activated carbon. A new way is reported to add the catalyst by catalyst-integration, which combines the carbon with catalyst to coexist in carbon surface. The catalyst content of the carbon prepared by catalyst-integration is 5.51%, and the same catalyst content carbon is also prepared by impregnation method. The differences between the two carbons are investigated. The carbon produced by catalyst-integration has both strongly physical and chemical adsorption property, and catalyst has no effect on the physical adsorption. The catalyst-integration carbon in comparing with impregnation carbon has larger H2S adsorption capacity no matter at oxygen and oxygen-free conditions. The H2S breakthrough capacity of catalyst-integration carbon reaches 0.13 g/cm3. Raw carbon after impregnation causes the decrease of pore volume and surface area. The carbon prepared by catalyst-integration technology has no effects on the pore volume and reduce surface area. The influence of organic on the H2S adsorption and carbon fired after saturation are also investigated. The results show that catalyst-integration carbon has better adsorption performance, and lower risk of spent carbon fire. In addition, the ignition temperature of the catalyst-integration carbon reaches 507°C. Meanwhile, the related samples are characterized by Brunauer–Emmett–Teller, scanning electron microscopy and X-ray diffraction.

Preparation of fly ash-based flocculant and flocculation performance

Using fly ash from a thermal power plant in Yingkou City as raw material, The inorganic polymer flocculant polyaluminum ferric chloride (PAFC) was prepared by sodium carbonate impregnation, high temperature roasting activation, and acid leaching. The influence of activation temperature and activation time on the leaching of aluminum and iron was investigated through single factor test and orthogonal test. The PAFC preparation conditions were optimized, and the prepared PAFC flocculant product was applied to kaolin turbidity water. The test results showed that the content of aluminum in fly ash was 7.08%, and the content of iron was 4.95%. The mass ratio of the activator sodium carbonate and fly ash was 10:7, the activation temperature was 800°C, and the activation time was 2h. The leaching rates of aluminum and iron were the highest, 88.31% and 53.66% respectively. The optimal conditions for the preparation of the flocculant were as follows: the molar ratio of aluminum to iron was 5.7:1, and the reaction time was 1.5h. The liquid product obtained under these conditions was yellowish brown, and the solid product obtained after being dried was yellow powder.

Ni-N4 sites in a single-atom Ni catalyst on N-doped carbon for hydrogen production from formic acid

The purposes of this research were to synthesize single-atom 1 wt% Ni catalysts for the hydrogen production from formic acid using a simple impregnation of N-doped carbon with Ni acetate, to elucidate the nature of the Ni site using a combination of experimental methods with density functional theory calculations, to propose a reaction mechanism with this Ni site and to compare the catalytic properties of the single-atom catalysts with those of a traditional Ni catalyst with nanoparticles (3.9 nm). We found that the single Ni atom formed a Ni-N4 site in a double vacancy of curved N-doped graphene. Mass-based catalytic activities of the single-atom and traditional catalysts were close. The mechanism of the reaction involved the formation of formate through participation of the Ni and N atoms. The highest energy barrier (1.088 eV) was determined for the step of recombination of hydrogen atoms. This barrier corresponded well to the experimental apparent activation energy.

Вивчення кінетики просочення базальтових, вуглецевих, оксидних волокон розплавами алюмінію та його сплавами

Wetting studies were performed by the sessile drop method using the capillary purification method of melt during the experiment in a vacuum of 2·10-3 Pa in the temperature range of 600–700 oC. The use of a dropper allows separate heating of the melt and the substrate, capillary and thermo vacuum cleaning of the melt, as well as thermo vacuum cleaning of the coatings surface. This is a model scheme of the impregnation process of non-metallic frames with matrix melts in the manufacture of composite materials by spontaneous free impregnation. Vanadium, copper and nickel metals were chosen for the coatings, which were sprayed on the materials by electron beam evaporation of metals in vacuum, and titanium, nickel powders for the coatings were used. The nature of the wetting angle dependence on the film thickness is a linear decrease in the angle with increasing film thickness. Studies have shown the possibility of using double films vanadium–copper, vanadium–nickel for the manufacture of composite materials from basalt fibers. The process of impregnation of basalt, carbon and oxide fibers with aluminum melts and its alloy with silicon in the temperature range 650–700 oC has been studied. The metal titanium, nickel powder coatings and films vanadium–copper, vanadium–nickel for the method of spontaneous free impregnation were used. Speciments of the composite material were obtained and the limit of destruction of these samples was determined. The bend strength of composites (basalt fiber 200 μm) is 270 MPa. Keywords: spontaneous free impregnation, composites, aluminium melts, basalt, carbon, oxide fibers, wetting, metal coatings and coverings.

Lynnia grapsolytica n. gen, n. sp. (Ciliophora: Apostomatida: Colliniidae), a Deadly Blood Parasite of Crabs with a Novel Pseudocytopharynx.

We describe a new genus and species of blood-dwelling apostome ciliate, Lynnia grapsolytica n. gen., n. sp. (Apostomatida: Colliniidae). A distinct kinety "hook" pattern on the tomite's posterior ventral face, coupled with its marine habitat and use of a decapod host, readily distinguishes this ciliate from all known colliniids. We detected the parasite in ~12% of Pachygrapsus crassipes (Brachyura: Grapsidae) crabs in a California estuary and confirmed its presence at a Baja California rocky intertidal site. As existing methods failed to adequately stain this ciliate, we developed a new miniaturized silver carbonate impregnation staining method that produced excellent somatic and nuclear stains in all five observed cell types. A possibly unique trait is the active invagination of the tropho-tomont's anterior to form a temporary "pseudocytopharynx," likely used for feeding. Histological examination revealed that the ciliate invaded and damaged skeletal muscle, the heart, connective tissues, and gonads. Survivorship analysis indicated that infected crabs experienced 2.6 times greater daily mortality than uninfected crabs. Laboratory and field experimental infection attempts failed, suggesting a complex life cycle with outside-host development. Phylogenetic analysis at the 18S and COI loci confirmed the ciliate's placement in the Colliniidae. We emend the diagnosis of Family Colliniidae.

Catalytic pyrolysis of wood-plastic composite waste over activated carbon catalyst for aromatics production: Effect of preparation process of activated carbon

In this work, the catalytic pyrolysis of a corn stalk/high-density polyethylene composite for aromatics production over activated carbon in a fixed-bed reactor was investigated. The effects of the carbonization temperature and H3PO4 impregnation ratio on the product distributions were studied. Increasing the H3PO4 impregnation ratio (0–2.0) and carbonization temperature (600–750 °C) was found to enhance the selectivity of aromatics. When the activated carbon was synthesized using an H3PO4 impregnation ratio of 1:1 and a carbonization temperature of 700 °C, the yield of aromatics reached a maximum of 86.11% and the selectivity of mono-aromatics reached 64.01%. Moreover, the catalytic performances of biochars obtained at various carbonization temperatures were also studied. No significant catalytic activity of biochar for the formation of aromatics was observed due to the absence of P-containing active functional groups. This work provides an approach for the conversion of wood-plastic composite waste into valuable aromatic production using a low-cost activated carbon catalyst.

Active Carbon Modified by Rhenium Species as a Perspective Supercapacitor Electrode

We have reported the synthesis of a new kind of composite combining a rhenium precursor and active carbon. Similarly to other refractory metals, rhenium exhibits several oxidation states that makes it an ideal candidate for redox-type energy storage materials. A simple impregnation of pretreated active carbon with ammonium perrhenate allowed to produce an electrode material with an enhanced specific capacitance. There was not any observed detrimental effect of metal species on the cycle life of the electrode. A small increase in charge transfer resistance was counter-balanced by the improved impedance in the whole examined range.

A multi-stage activated carbon impregnation system: Isotherms, kinetics and multi-objective modeling optimization

A multi-stage activated carbon impregnation system, with a special emphasis on solvent reuse, is introduced and optimized in this study. Experiments and modeling optimization are combined to simultaneously minimize the solute consumption and operating time for the system. The adsorption isotherm and kinetic models are well regressed based on a series of experiments on activated carbon impregnated in triethylene tetramine solution. A multi-objective nonlinear programming optimization framework is then formulated based on the regressed isotherm and kinetic models and material balance, including activated carbon, solute, water and impurities at each stage in the system. The AUGMECON method and global solver ANTIGONE are used to solve the challenging optimization problem, and the pareto optimal solutions are obtained. Additionally, a new dimensionless number is presented to further coordinate the operating parameters for the system. The result shows that the specific solute consumption and operating time are decreased by 65.11% and 85.88%, respectively.

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.

Thermal Protection Performance of Polymethylmethacrylate-Impregnated Porous Carbon Materials with Three Different Densities

The thermal protection performances of polymethylmethacrylate-impregnated porous carbon ablators with three different densities were examined in an arc wind-tunnel test. The more impregnated ablator exhibited significantly higher exhaust gas pyrolysis and heat absorption, which improved the recession resistance, the gas-blocking effect for convection heating, and the thermal insulation of the ablator. The improvement of the recession resistance resulting from the higher amount of impregnant was more significant at relatively low dynamic pressures, and the gas-blocking effect for convection heating was more pronounced at relatively low heat fluxes. In contrast, the improvement of the thermal insulation was more significant at higher heat fluxes. In addition, all the effects of the porous carbon impregnation on the ablator were more pronounced at longer heating times.

Synthesis and Characterization of Nano Activated Carbon from Annatto Peels (Bixa orellana L.) Viewed from Temperature Activation and Impregnation Ratio of H3PO4

Nano activated carbon is activated carbon with nano-sized carbon particles and can be synthesized from cellulose-containing materials such as the Annatto peels. In this study, the synthesis of nano activated carbon of the Annatto peels was carried out in terms of activation temperature variations and the carbon impregnation ratio of 50% H3PO4 acid and determining the characteristics of nano activated carbon from Annatto peels (NAPAC). The activation method used is the impregnation of carbon in 50% H3PO4 with a ratio of 1: 3; 1: 4; 1: 5; 1: 6; and 1: 7 (w/w) for 24 hours and heating at 400; 500; 600; 700; and 800 °C for one hour. Nano activated carbon from Annatto peels (NAPAC) was characterized by Infrared Spectrophotometer (FTIR), X-ray Diffractometer (XRD), and Transmission Electron Microscope (TEM). The results of the study showed that the NAPAC can be synthesized from Annatto peels with activation by 50% H3PO4 at the temperature of 500°C and the impregnation ratio of 1:5 (w/w). The result of characterization using FT-IR, XRD and TEM showed that NAPAC contains a group of functions O-H, C-H, C=, C=C dan C-O/P=O with an amorphous carbon structure and the range of particles diameter at 22-36 nm

Preparation of Cu-Loaded Biomass-Derived Activated Carbon Catalysts for Catalytic Wet Air Oxidation of Phenol

A series of Cu-loaded biomass-derived activated carbon (Cu/AC) catalysts with various impregnation ratios were prepared by precursor impregnation (PI) and activated carbon impregnation (ACI) method...

Morphological and Morphometric Characterization of Eodinium posterovesiculatum (Ciliophora, Ophryoscolecidae) in Brazilian Cattle

The morphological variability of Eodinium posterovesiculatum (Ciliophora, Trichostomatia) has been interpreted in different ways: four distinct species or four morphotypes of the same species. The present study aims to perform morphological and morphometric comparative analysis of the four morphotypes found in cattle from the southeastern region of Brazil. Ruminal content samples were obtained from four Holstein x Gir cattle and fixed at 18.5% formalin for morphological analysis. Morphometry was performed based on individuals stained with Lugol's solution [1]. The infraciliary bands were stained using silver carbonate impregnation technique [2]. Morphological and morphometric characterizations, supported by literature, suggest that the four morphotypes of E. posterovesiculatum are actually a single polymorphic species due to small morphometric differences and mostly identical morphological characters, with the format of the caudal processes being the only morphological characteristic that sets them apart.

Development of an activated carbon impregnation process with iron oxide nanoparticles by green synthesis for diclofenac adsorption.

The objective of this study was to impregnate the surface of palm coconut activated carbon with nanoparticles of iron compounds using Moringa oleifera leaf extracts and pomegranate leaf by a green synthesis method and to evaluate its adsorption capacity for sodium diclofenac. The adsorbent material was characterized by zeta potential, X-ray diffraction (XRD), N2 adsorption/desorption (BET method), transmission electronic microscopy (TEM), and scanning electronic microscopy (SEM) coupled to dispersive energy spectrometry X-ray (EDX) methods. To evaluate the adsorption capacity of sodium diclofenac, the influence of pH, kinetics, isotherms, and thermodynamic properties were analysed. The impregnated adsorbents showed efficiency in the adsorption of sodium diclofenac. The kinetic model that best fit the experimental data was the pseudo-second-order model, and the equilibrium model was the Langmuir model. As for the thermodynamic study, it was verified that the adsorption reaction for all adsorbents occurs in a spontaneous, favourable way, and it is endothermic by physisorption. Therefore, this process is promising because it is a clean and non-toxic method when compared with chemical methods for the synthesis of nanoparticles.

Electrical properties of 3D printed graphite cellular lattice structures with triply periodic minimal surface architectures

Selective laser sintering (SLS) provides a way to fabricate 3D graphite parts, and allows the fabrication of complex free-form geometry that could not have been achieved using traditional manufacturing techniques. This study investigates the manufacturability and electrical properties of SLS produced graphite cellular lattice structures, which are designed by the mathematically-known triply periodic minimal surfaces (TPMS). TPMS are a class of non-self-intersecting surfaces created by local surface area minimization principle, which can provide advanced or multifunctional performance for a range of applications. Here, the effective electrical conductivity of three well-know TPMS architectures (Gyriod, IWP and Diamond) of different unit cell sizes is investigated experimentally and numerically [using finite element analysis (FEA)]. The results show that the structure made by SLS has a good geometric agreement with the original design models. When the volume fraction is constant, the structure with more unit cells exhibits better electrical properties. Moreover, the structure based on Gyriod shows the best electrical performance and after impregnation and high-temperature carbonization, the electrical conductivity of the sample can reach 317 S cm−1.