Krypton Adsorption Research Articles

Understanding and Predicting the Spatially Resolved Adsorption Properties of Nanoporous Materials.

Using knowledge from statistical thermodynamics and crystallography, we develop an image-image translation model, called SorbIIT, that uses three-dimensional grids of adsorbate-adsorbent interaction energies as input to predict the spatially resolved loading surface of nanoporous materials over a broad range of temperatures and pressures. SorbIIT consists of a closed-form differential model for loading-surface prediction and a U-Net to generate spatial differential distributions from the energy grids. SorbIIT is trained using the energy grids and adsorbate distributions (obtained from high-throughput simulations) of 50 synthesized and 70 hypothetical zeolites and applied for predicting the adsorption of carbon dioxide, hydrogen sulfide, n-butane, 2-methylpropane, krypton, and xenon in other zeolites from 256 to 400 K. Employing a quadratic isotherm model for the local differentiation, SorbIIT yields mean R2 values of 0.998 for total adsorption and 0.6904 for local adsorption with a resolution of 0.2 Å, and a value of 0.721 for the structural similarity of the local loading distribution.

Natural gas desorption versus laboratory gas adsorption with pore shrinkage

To perform hydro-mechanical experiments on sorptive geomaterials, the gas is injected into bulk of the specimen to re-saturate it representing its in-situ state, and adsorption is monitored until gas equilibrium is reached. We show in this study that this experimental procedure does not reflect the in-situ state of the sample leading to potentially significant errors. We measured the carbon dioxide (CO2) adsorption capacity of the coal specimen (free of gas) and its powder with different particle sizes and compared the results with field desorption data. Experimental results indicate an increase in coal adsorption capacity with decrease in coal particle size. Interestingly, the field data exhibits much higher desorbed gas amount compared to laboratory-measured adsorption capacity of coal powder with smallest measurable particle size under the same gas pressure. To shed light on the observation of field desorption – laboratory adsorption hysteresis, the micro-scale gas adsorption experiments combined with X-ray micro-Computed Tomography (XRCT) measurements were conducted where an intact specimen was imaged before (dry state) and after Krypton injection. The analysis of the XRCT images indicates that the Krypton adsorption closes/reduces the aperture of pre-existing fractures in the specimen. In addition, the Krypton diffuses only in a small region near pre-existing fractures despite its adsorption measurement indicating gas equilibrium and specimen saturation. This observation proposes that significant portion of pores exposed to Krypton experienced a size reduction by swelling resulting in partial saturation of the specimen. This patrial saturation at laboratory conditions evidently cannot resemble the in-situ state of gas sorption capacity.

Continuum-Scale Gas Transport Modeling in Organic Nanoporous Media Based on Pore-Scale Density Distributions

SummaryWe present a continuum-scale mass transport model informed by pore-scale density distribution for gas diffusion through organic nanoporous media. A diffusion model and a sorption model are developed by considering multiple transport and storage mechanisms, including bulk diffusion and Knudsen diffusion for free phase, and surface diffusion and multilayer adsorption for sorbed phase. The continuum-scale diffusion equation is derived based on the free-phase concentration for the overall mass conservation of free and sorbed phases, carrying a newly defined effective diffusion coefficient and capacity factor to account for multilayer adsorption. Diffusion in free and sorbed phases is coupled with the sorption model, which provides pore-scale multilayer adsorption properties by utilizing a pore-scale simplified local density (SLD) method combined with the modified Peng-Robinson equation of state (PR-EOS) for confinement effect. The model was first implemented to analyze adsorption data from a krypton (Kr) adsorption experiment on graphite. Then, we applied the developed diffusion model to conduct the sensitivity analysis of the effects of pore size on gas transport for Kr-graphite and methane-coal systems. The model was finally used to study Kr diffusion profiles through a coal matrix obtained by using X-ray micro-computed tomography (microCT) imaging. The results show that the sorbed phase occupies most of the pore space in organic nanopores with less than 10 nm due to multilayer adsorption, and surface diffusion contributes significantly to the total mass flux. Therefore, neglecting the volume of sorbed phase and surface diffusion in organic nanoporous rocks may result in considerable errors in the prediction of hydrocarbon production. We also compared Brunauer-Emmett-Teller (BET) and Langmuir models by analyzing adsorption data for the wide pressure range up to the saturation pressure. The comparison between BET and Langmuir models shows that the Langmuir model can only match the adsorption isotherm at low pressure and yield lower effective surface diffusion coefficients. Therefore, implementing a Langmuir model may be erroneous for organic nanoporous media with strong adsorption capacity, particularly when pore pressure is high.

Aging of microplastics increases their adsorption affinity towards organic contaminants

When released in the environment, microplastics undergo surface weathering due to mechanical abrasion and ultraviolet exposure. In this study, the adsorption of two model contaminants, phenanthrene and methylene blue, by weathered high density polyethylene (HDPE) and polypropylene (PPE) was evaluated to understand how the microplastics’ aging influences contaminant adsorption. Microplastics were aged through an accelerated weathering process using ultraviolet exposure with or without hydrogen peroxide. Adsorption isotherms were conducted for both contaminants on pristine and aged microplastics. The adsorption of organic contaminants was higher on aged microplastics than on pristine ones, with methylene blue having the highest affinity increase with aging at 4.7-fold and phenanthrene having a 1.9-fold increase compared to the pristine particles. To understand the mechanisms involved with higher adsorption of contaminants by aged microplastics, changes in the specific surface area and surface chemistry of aged microplastics were characterized by Fourier Transform Infrared Spectroscopy, X-ray Photoelectron Spectroscopy, zeta potential, X-ray tomography, and Brunauer–Emmett–Teller krypton adsorption analyses. The results of this study show that oxidation of microplastics can enhance the adsorption of organic contaminants, which may increase their role as vectors of contaminants in the aquatic food chain.

Extrusion-Spheronization of UiO-66 and UiO-66_NH2 into Robust-Shaped Solids and Their Use for Gaseous Molecular Iodine, Xenon, and Krypton Adsorption.

The use of an extrusion-spheronization process was investigated to prepare robust and highly porous extrudates and granules starting from UiO-66 and UiO-66_NH2 metal-organic framework powders. As-produced materials were applied to the capture of gaseous iodine and the adsorption of xenon and krypton. In this study, biosourced chitosan and hydroxyethyl cellulose (HEC) are used as binders, added in low amounts (less than 5 wt % of the dried solids), as well as a colloidal silica as a co-binder when required. Characterizations of the final shaped materials reveal that most physicochemical properties are retained, except the textural properties, which are impacted by the process and the proportion of binders (BET surface area reduction from 5 to 33%). On the other hand, the mechanical resistance of the shaped materials toward compression is greatly improved by the presence of binders and their respective contents, from 0.5 N for binderless UiO-66 granules to 17 N for UiO-66@HEC granules. UiO-66_NH2-based granules demonstrated consequent iodine capture after 48 h, up to 527 mg/g, in line with the pristine UiO-66_NH2 powder (565 mg/g) and proportionally to the retaining BET surface area (-5% after shaping). Analogously, the shaped materials presented xenon and krypton sorption isotherms correlated to their BET surface area and high predicted xenon/krypton selectivity, from 7.1 to 9.0. Therefore, binder-aided extrusion-spheronization is an adapted method to produce shaped solids with adequate mechanical resistance and retained functional properties.

Argon, krypton and xenon adsorption coefficients on various activated carbons under dynamic conditions

Argon, krypton and xenon adsorption coefficients on various activated carbons under dynamic conditions

Digitization of Adsorption Isotherms from "The Thermodynamics and Hysteresis of Adsorption".

Sorption isotherms collected from tables in the seminal dissertation, “The Thermodynamics and Hysteresis of Adsorption” by A. J. Brown, have been digitized and made publicly available, along with supporting software scripts that facilitates usage of the data. The isotherms include laboratory measurements of xenon, krypton, and carbon dioxide adsorption (and, when possible, desorption) isotherms on a single sample of Vycor glass1, at various temperatures including subcritical conditions for xenon and krypton. The highlight of this dataset is the collection of “scanning” isotherms for xenon on Vycor at 131 K. The scanning isotherms examine numerous trajectories through the adsorption-desorption hysteresis region, such as primary adsorption and desorption scanning isotherms that terminate at the hysteresis boundary, secondary scanning isotherms made by selective reversals that return to the boundary, and closed scanning loops. This dataset was originally used to test the independent domain theory of adsorption and continues to support successor theories of adsorption/desorption scanning hysteresis including more recent theories based on percolation models. Through digital preservation and release of the tables from Brown’s dissertation, these data are now more easily accessible and can continue to find use in developing models of adsorption for fundamental and practical applications.

Tuning surface inductive electric field in microporous organic polymers for Xe/Kr separation

Understanding how the local polar sites in porous adsorbent surface affect their adsorption performance remains a challenge in molecular related separation process. We present an in-depth study of silver (Ag), cobalt (Co), iron (Fe) and nickel (Ni) ions on hyper cross-linked microporous organic polymer (HCP) in which all metal ions act as polar sites for xenon (Xe) and krypton (Kr) adsorption. Surface electrostatic potential analysis revealed that Xe adsorption strength at metal sites differs from that of Kr. Charge density difference analysis proved that the precise charge transfer between metal ions and Xe. These effects could strengthen the inductive energy caused by surface electric field for Xe adsorption in metal ions decorated HCP (HCP-M). Adsorption kinetics experiments showed that the adsorption rates of Xe on HCP-M (20.45–47.19 cm3/(cm3·s)) are much higher than that of Kr (9.45–17.38 cm3/(cm3·s)). The HCP-Ni can adsorb 90 ml Xe per volume with 16.20 Xe/Kr selectivity in Xe, Kr and N2 ternary gas mixture, which was among the well performing porous organic polymers reported. The Xe/Kr adsorptive separation performance of HCP-M stemmed mainly from the optimized inductive energy and the small-pore confinement effect of HCP-M, which could significantly facilitate preferential selective adsorption of Xe over Kr.

Impact of Plasma and Thermal Treatment on the Long-term Performance of Vanadium Redox Flow Electrodes – Significance of Surface Structure vs Oxygen Functionalities

Graphite felt (GF) electrodes of vanadium redox flow batteries show enhanced performance when thermally treated before their assembly. Thermal treatment works by simultaneously increasing electrode wettability, kinetic activity, and total surface area (TSA). This study examines these performance determining yet inseparable effects, especially considering the electrodes’ long-term operation. We exposed GF electrodes to 5 min plasma treatment, ensuring equal wettability, and thermally treated them in air at 400 °C for different durations. We then linked the resulting GF surface structure with the electrode performance, monitored with a high temporal resolution, and controlled electrolyte conditions. The performance, expressed in charge-transfer resistances and voltage efficiencies, correlated accurately with the thermal treatment times. According to XPS, against expectation, the thermal treatment decreased the number of surface oxygen functionalities. Instead, SEM and krypton adsorption revealed that the surface had become rougher, and the TSA increased. Upon corrosion, the surface presumably exposed more carbon edge sites being catalytically active, explaining the improved performance. Therefore, compared with the commonly suggested surface oxygen enrichment, increasing the GF surface roughness and TSA may be the more promising strategy to enhance and stabilize the long-term VRF electrode performance.

Fabrication of biodegradable particles with tunable morphologies by the addition of resveratrol to oil in water emulsions.

Particles for biomedical applications can be produced by emulsifying biocompatible polymers dissolved in an organic solvent in water. The emulsion is then transferred to an extraction bath that removes the solvent from the dispersed droplets, which leads to polymer precipitation and particle formation. Typically, the particles are smooth and spherical, likely because the droplets remain fluid throughout the solvent extraction process allowing minimization of surface area as the volume decreases. Few modifications to this technique exist that alter the spherical geometry, even though particle performance, from drug delivery to engaging cells of the body, can be tuned with morphology. Here we demonstrate that incorporation of resveratrol, with the aid of ethanol, into the oil phase of an emulsion of poly(lactide-co-glycolide) and dichloromethane in aqueous poly(vinyl alcohol) leads to a crumpled particle morphology. Video microscopy of particle formation revealed that during solvent extraction the droplet crumples in on itself, which does not occur when only ethanol is added to the emulsion. It is unclear why this occurs with resveratrol, but its hydroxyl groups appear to be optimally positioned because removal of the 4' hydroxyl or addition of a 3' hydroxyl resulted in a loss of crumpled particle morphology. We demonstrate that particle morphology can be tuned from that of a crumpled sheet of paper to a deflated sphere by switching out ethanol for a different cosolvent. We quantify the degree of particle deformation with surface area calculated from krypton adsorption isotherms and BET theory and find surface area correlates with resveratrol loading in the particle. Furthermore, spherical particles are achieved when ethyl acetate is used in lieu of dichloromethane and a cosolvent. We propose that during solvent extraction, resveratrol accumulates at the droplet surface where it inhibits polymer chain motion necessary to maintain a spherical geometry and the role of cosolvent is to redistribute resveratrol from the droplet bulk to its surface. This method of producing nonspherical particles extends to polycaprolactone and poly(L-lactic acid) and is compatible with the encapsulation of a hydrophobic fluorescent dye, suggesting hydrophobic bioactive agents could be encapsulated. Taken together, we demonstrate an ability to control morphology of biocompatible polymer particles produced by the widely practiced oil-in-water/solvent extraction protocol via the addition of resveratrol and a cosolvent to the oil phase. The methodology reported is straight forward, and scalable, and expected to be of utility in applications in which a deviation from the default smooth, spherical morphology is desired.

CCCM SPECIFIC SURFACE ESTIMATION IN PROCESS OF LOW-TEMPERATURE OXIDATION

The low-temperature oxidation process of carbon-carbon composite materials (CCCM) with a pyrocarbon matrix has been examined. Oxidation at temperatures of 450 to 700 °C is characterized by internal burnout of the carbon phase without a noticeable change in the experimental samples external volume. Oxidation resistance analysis of CCCM structural components was performed. CCCM and carbon fibers specific surface area were estimated by the low-temperature adsorption of nitrogen and krypton using the Brunauer-Emmett-Teller model and the theory of density functional model. Pore size distribution was calculated by the semi-empirical Horvath-Kawazoe method. A significant increase (about 10-15 times) in specific surface area of the composite material, together with a rise in free volume ~5%, was accompanied by total weight loss of about 5%. Specific surface area changes occur as a result of anisotropic etching of carbon fibers surface with the formation of micropores with 0.5–2.0 nm diameter range. Although macropores are formed mainly due to the oxidation of thermosetting binder pyrolysis residue, they do not contribute to the specific surface increase but solely provide access to micropores. Microporosity evolution leads to an increase of structural discontinuity degree and, ultimately, to the loss of matrix-filler contact boundary. As a result, an overall weakening of material mechanical characteristics is to be noted. Thus, oxidative degradation is closely related to the increase in void space. A follow-up study is on-going. In fact, an open question remains, namely whether the oxidative process occurs differently in the micropores of diameter less than 2 nm and how it may contribute to the oxidative stress resistance behavior of CCCM.

Oscillatory Behavior in Oxidation of Propane Over Nickel Foil and Films

The oxidation of propane was studied over Ni foil, a thick Ni/Si film, and a thin Ni/Si film in a flow reactor under oxygen-deficient conditions at a total pressure near 1 mbar. The thickness of the foil was 125 µm, while the thickness of the films was 20 and 1.5 µm, respectively. It was shown that regular self-sustained reaction-rate oscillations arise only over the Ni foil and the thick Ni/Si film. The relaxation-type oscillations appear at 700 °C after an induction period of approximately 50 min, which is accompanied by the formation of a rough and porous structure over their surfaces. According to krypton adsorption measurements, the effective surface area of the treated catalysts increases significantly. CO, CO2, H2, and H2O were detected as products in the gas phase. The results of operando X-ray absorption spectroscopy study indicate that the oscillations originate due to periodical oxidation and reduction of nickel. The highly active state is Ni in the metallic state, while the transition to the poorly active state is accompanied by the growth of NiO layer on the catalyst surface. The upper layer of the catalysts with a thickness of at least 15 nm is involved in the oxidation/reduction process. In contrast, no oscillations appeared in the oxidation of propane over the thin Ni/Si film. In this case, the thickness of the Ni layer is not sufficient for the formation of a porous structure over the thin Ni film. As a result, the thin Ni film cannot provide high activity in the catalytic oxidation of propane that is sufficient for the self-sustained oscillations to occur. The reasons that lead to oscillatory behavior in the oxidation of propane over nickel are discussed.

BET surface area measurement of commercial magnesium stearate by krypton adsorption in preference to nitrogen adsorption.

Magnesium stearate is an extremely common pharmaceutical excipient and the measurement of BET surface area via nitrogen adsorption is undertaken during pharmaceutical formulation and manufacture. In this paper, four commercial magnesium stearate materials in mono- and di-hydrated forms are analysed by nitrogen and krypton adsorption for the calculation of BET surface area. BET surface area via nitrogen adsorption is shown to be erroneously high due to a structural swelling and adsorbate encapsulation effect occurring throughout the BET range and which should preclude the use of BET theory. However, with krypton adsorption this effect commences at higher adsorption pressures and it is possible to calculate BET surface area which better represents the true surface area of the material. The disparity between nitrogen and krypton adsorption is greater for the di-hydrate form: the mean average BET surface area of 10 samples from the same di-hydrate containing batch are 23.18 m2g-1 via nitrogen adsorption and 6.78 m2g-1 via krypton. It is also shown than the standard deviation of BET surface area across 10 analyses of each of the four batches is considerably lower via krypton adsorption. Finally, an analytical protocol for krypton adsorption onto magnesium stearate for BET surface area measurement is established.

Preparation of cyclodextrin-based porous polymeric membrane by bulk polymerization of ethyl acrylate in the presence of cyclodextrin

We disclose an efficient synthesis to prepare polymeric membranes containing cyclodextrins (CDs). Bulk polymerization of ethyl acrylate containing peracetylated γ-CD (PAcγCD) yields a porous polymeric membrane containing CDs [CD membrane (BP)]. Krypton adsorption measurements reveal that the CD membrane (BP) has a porous structure. The specific surface area of the CD membrane (BP) is 10 times higher than that of a CD-based polymeric membrane prepared via solution casting using a solution containing poly(ethyl acrylate) and PAcγCD. Due to the large specific surface area of the CD membrane (BP) and the molecular recognition of CD, the capabilities and selectivity of CD membrane (BP) to separate bisphenol A as an environmental pollutant from water are demonstrated.

Final report of CCQM-K153 Measurement of Specific Adsorption A [mol/kg] of N2 and Kr on nonporous SiO2 at LN temperature (to enable a traceable determination of the Specific Surface Area (BET) following ISO 9277)

CCQM key comparison K-153 Measurement of Specific Adsorption A [mol/kg] of N2 and Kr on nonporous SiO2 at LN temperature (to enable a traceable determination of the Specific Surface Area (BET) following ISO 9277) has been performed by the Surface Analysis Working Group (SAWG) of the Consultative Committee for Amount of Substance (CCQM). The objective of this key comparison is to compare the equivalency of the National Metrology Institutes (NMIs) and Designated Institutes (DIs) for the measurement of specific adsorption, BET specific surface area) of nonporous substances (sorbents, ceramics, catalytic agents, etc) used in advanced technology.In this key comparison, a commercial nonporous silicon dioxide was supplied as a sample. Eight NMIs participated in this key comparison, but only five NMI's have reported in time. All participants used a gas adsorption method, here nitrogen and (or) krypton adsorption at 77.3 K, for analysis according to the international standards ISO 15901-2 and 9277.In this key comparison, the degrees of equivalence uncertainties for specific adsorption nitrogen and krypton, BET specific surface area were established.KEY WORDS FOR SEARCHnonporous SiO2, Specific Adsorption of N2 and Kr, BET specific surface areaMain textTo reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

Electrochemical characterization of porous boron-doped diamond prepared using SiO2 fiber template

Porous boron-doped diamond (BDD) is fabricated by consecutive plasma enhanced chemical vapor deposition on a 3D porous SiO2 fiber template deposited by spin coating (SC). The fabricated highly doped and mechanically stable porous BDD layers are characterized by scanning electron microscopy (SEM) and Raman spectroscopy. The roughness factor of the prepared porous BDD, depending on the number of porous layers, was determined from cyclic voltammetry (RFCV) and from krypton adsorption isotherms – BET, (RFBET). Differences in determination of the roughness factor using these two methods are discussed. Electrochemical measurements (cyclic voltammetry and galvanostatic charge/discharge cycling) of porous BDD are performed in aqueous electrolyte solutions with different composition and pH values. The highest electric double-layer capacitance of ca. 2 mF·cm−2, related to the projected geometric (2D) surface area, is obtained for the thickest (26 μm) porous BDD electrode measured in 0.5 M H2SO4 electrolyte solution. The capacitance of the same porous BDD normalized to the total physical surface area (3D) determined by BET is 45 μF·cm−2. The electrocatalytic activity of porous BDD electrodes is studied using a hexaammineruthenium(III/II) redox probe, and the electrochemical cycle stability is determined by galvanostatic charge/discharge. The charge retention of the thickest porous BDD samples after removal of non-diamond impurities by an oxidative treatment is ca. 77% after 3000 cycles.

Comparison of the Adsorption Transitions of Methane and Krypton on Graphite at Sub-Monolayer Coverage

Simulation of gas adsorption on graphite is commonly carried out using a model that assumes that graphite has an energetically homogeneous surface, constant interlayer spacing, and isotropically polarizable carbon atoms. This simple model fails to describe experimental isotherms and isosteric heats for many gas/graphite pairs. In this paper, we investigate the adsorption of krypton and methane on graphite, using a recently developed molecular model for graphite, that has been shown to improve the description of experimental isotherms and isosteric heats for nitrogen and argon.(1−3) Although the collision diameters of krypton and methane are almost the same, their isotherms and heats are significantly different. With the aid of detailed microscopic analysis, we establish the mechanism underlying the transitions in adsorbate loading as well as the origin of the spike in the experimental isosteric heat versus loading for methane and krypton. The first adsorbate layer of both adsorbates exhibits the transitio...

Thermodynamics of krypton adsorption on microporous carbon adsorbent at high pressures

The behavior of the thermodynamic functions for the adsorption system krypton—microporous carbon sorbent ACC is described. The dependences of the differential molar isosteric heat of adsorption, entropy, enthalpy, heat capacity, and differential molar energy of the adsorption system on the adsorption equilibrium parameters were studied over the temperature range from 178 to 393 K and at pressures ranging from 1 to 6•106 Pa. Consideration of the non-ideality of gas phase and non-inertness of the adsorbent leads to a temperature dependence of the thermodynamic functions of the studied adsorption system, especially in the range of high pressures of the adsorptive. The non-ideality of the gas phase and the energetics of the adsorbent—adsorbate system exert the most significant effect on the thermodynamic functions. The non-inertness of the adsorbent in the investigated range of parameters of the adsorption system has a weak effect on the thermodynamic functions of adsorption. In the region of high filling of ACC micropores, the entropy increases, indicating the existence of processes, which change the structure of the adsorbate in the micropores, in particular, to form associates.

Adsorption of radioactive iodine and krypton from off-gas stream using continuous flow adsorption column

A novel Engelhard Titanosilicate – 10 (ETS-10) supported 10wt% hollow carbon nano-polyhedron (10wt% C@ETS-10) sorbent developed in our laboratory was investigated for adsorption of the radioactive iodine and krypton from off-gas stream using a continuous flow adsorption column. Adsorption experiments were performed to determine the capacity of 10wt% C@ETS-10 sorbent for iodine and krypton in multicomponent mixture system by varying operating parameters, such as inlet concentration of iodine (I2) and krypton (Kr), and adsorption column temperature. Pristine and used sorbents were characterized by scanning electron microscopy-energy dispersion spectroscopy (SEM-EDS), X-ray photoelectron spectroscopy (XPS) and Raman spectroscopy to identify the morphology, elemental and vibration analysis of the sorbent before and after the experiments. EDS and XPS spectra of the used samples clearly indicate the presence of iodine on the sorbent. Multicomponent sorption capacities of I2 and Kr of 10wt% C@ETS-10 sorbent calculated from the breakthrough curves at 20°C at 25ppm I2 and 70ppm Kr balanced with nitrogen were found to be 41.5 and 0.0323mgg−1, respectively. Sorption data was found to be best fitted by the Langmuir as well as Freundlich isotherm model. Experimental data were analyzed by Thomas, Yoon-Nelson, and Bohart-Adams sorption kinetics models to predict the breakthrough curves and calculate the characteristic parameters of the column that are useful for process design for the multicomponent system. Results show that 10wt% C@ETS-10 sorbent has potential sorbent for adsorption of multicomponent (I2 and Kr) from off-gas stream.

Характеризация удельной поверхности древесины при эффекте памяти формы

The change of the specific wood surface at the shape memory effect is considered in this paper. The study was conducted using sorptive analyzer of specific surface and distribution of pores according to the size of Quadrasorb SI. Specific surface of samples SSA, сm2/g, was found by the low-temperature adsorption of krypton at liquid nitrogen temperature (77K) and was cal-culated by the Brunauer-Emmett-Teller (BET) method. The samples of beech, pine, oak sliced veneer and birch rotary-cut veneer were investigated.