Wide Pore Size Distribution Research Articles

<i>In Vitro</i> Characterization of 3D Beta-Tricalcium Phosphate Scaffolds Reinforced with Phosphate Based-Bioactive Glass for Bone Replacement

Bone tissue engineering is an excellent alternative to reduce bone disorders and conditions, by inducing new functional bone regeneration starting from the synthesis of the biomaterials and then the combination of cell and factor therapy. In the present contribution, the scaffolds were made with a ratio of 80 wt.% of β-TCP and 20 wt. % of phosphate-based bioglass, in addition the phosphate-based bioglass was reinforced with zirconia in different amounts (0, 0.5 and 1.0 mol%) with the aim to reduce the dissolution rate, improve the osteoconduction and the osteogenesis of the bone tissue. The results obtained by μCT of the scaffolds containing zirconia showed a wide pore size distribution between 1.5 and 303 μm. AlamarBlue assays showed that the cell proliferation of MC3T3-E1 preosteoblasts scaffolds were sixfold increase in relation to the number of the initial cells. FE-SEM helped to observe the cauliflower structure of HA and DRX showed that crystalline phases formed after heat treatment were (NaCaPO4 and NaZr5PO4) owing both to the crystallization and combination of the bioglass and β-TCP .

Frequency and temperature dependent electrochemical characteristics of carbon-based electrodes made of commercialized activated carbon, graphene and single-walled carbon nanotube

Electrochemical double-layer capacitors, consisted of electrodes made of commercialized activated carbon (AC), graphene, and single-walled carbon nanotube (SWCNT) are fabricated and investigated, in order to reveal the dependency of their performance on charging/discharging frequency and operating temperature. Their electrochemical properties are quantified by means of cyclic voltammetry, constant current charge/discharge and electrochemical impedance spectroscopy. Through varying the applied frequency and operating temperature, correlations are identified between the capacitive and resistive behaviors of these electrodes and their representative porous structures including morphology, surface area, and pore size distribution (PSD). It is observed that the graphene and SWCNT electrodes, possessing larger meso-pores with a wide PSD, show better capacitive stabilities and shorter current response periods under high-frequency operations. They however exhibit a large variation of internal resistance over the operating temperature range of −30 °C to 60 °C. In contrast, the AC electrode, having a narrow PSD with mainly micro-pores, shows an increasing resistance and subsequently a longer current response period with increasing the applied frequencies. The dependency of its capacitance and resistance on temperature is found to be insignificant. A recently proposed equivalent circuit model is used to elucidate the activation energies of ion kinetics and diffusion processes in these electrodes.

Effects of Piper cubeba L. essential oil on methicillin-resistant Staphylococcus aureus: an AFM and TEM study.

The increasing prevalence of antibiotic-resistant bacteria is creating a real challenge for health care systems worldwide, making the development of novel antibiotics a necessity. In addition to the development of new antibiotics, there is an urgent need for in-depth characterization of the mechanisms of bacterial resistance toward new drugs. Here, we used essential oils extracted in our laboratory from Piper cubeba against methicillin-resistant Staphylococcus aureus ATCC 43300, one of the most prominent antibiotic-resistant bacteria. Effects of the essential oils extracted from Pcubeba on bacteria were mainly evaluated using 2 powerful microscopy techniques: atomic force microscopy and transmission electron microscopy. High-resolution atomic force microscopy images of the cells were obtained close to their native environment by immobilizing the cells on porous Polyether sulfone membranes, which were prepared in our laboratory with a wide range and distribution of pore sizes and depth. Inhibition zones (mm) and minimum inhibitory concentrations were determined. Two different concentrations of the oil were used to treat the cells: 50μg/mL minimum inhibitory concentration and 25μg/mL. The 50μg/mL oil solution caused severe damage to the bacterial cells at microscopic levels while the 25μg/mL solution showed no effects compared to the control. However, at nanoscopic levels, the 25μg/mL oil solution caused significant changes in the cell wall, which could potentially impair bacterial activities. These results were also confirmed by transmission electron microscopy micrographs. Our results indicate that the extract has a good biological activity against methicillin- and oxacillin-resistant Saureus and that it acts on the cell wall and plasma (cytoplasmic) membrane.

Exploiting the effects of catalyst geometric properties to boost the formation of light olefins in Fischer-Tropsch synthesis: Statistical approach for simultaneous optimization

A statistical study was carried out to investigate simultaneous effects of different geometrical properties of the catalyst on the extent of light olefins in Fischer-Tropsch synthesis. Applying Taguchi design of experiment, a total of nine impregnated CoMnCe/SiO2 catalysts were prepared and tested in a fixed-bed reactor under the following operating conditions: T = 533.15 K, 558.15 K and 583.15 K, P = 2 bar, H2/CO = 2 and GHSV = 4500 hr−1. Specific surface area, pore diameter, pore volume, and pore structure (pore size distribution) were considered as the main geometrical factors which were controlled by tuning such sol-gel parameters in silica synthesis as Reynolds (Re) and Froude (Fr) dimensionless numbers as well as acid dripping time (Ө), and acid normality (N). Analysis of variance demonstrated that, both of specific surface area and pore volume imposed significant effects on the production of lower olefins. Statistical analysis indicated that, the mesoporous catalyst with a wide pore size distribution and large specific surface area and pore volume favored (i.e. maximized) the production of light olefins. These optimum geometries were achieved by setting the silica synthesis parameters to Re = 250,000, Fr = 0.213, Ө = 30 min, and N = 6.

Effects of mineralogy on petrophysical properties and permeability estimation of the Upper Triassic Yanchang tight oil sandstones in Ordos Basin, Northern China

This paper aims to analyze the effects of mineralogy on petrophysical properties and evaluate the performance of eight permeability estimation models in tight oil sandstones. The results include mineralogy, pore size distribution, porosity, and permeability. The evaluated eight permeability models are Purcell, Winalnd, Swanson, Thomeer, Wells-Amaefule (W-A), Katz-Thompson (K-T), Pittman and Dastidar models. The experimental results indicate that the samples are rich in quartz (averages 41.5%), feldspar (30.0%), and clays (18.5%); have a wide pore size distribution mainly in the nanometer scale (9.2nm–1μm); and have low porosity (11.07% on average) and ultralow permeability (0.22mD). Quartz and feldspar preserve the primary pores by supporting the overburden pressure, and feldspar further enhances the porosity by forming secondary dissolution pores. Mixed layer of illite/smectite (I/S) and illite significantly decrease porosity while chlorite preserves the primary pores by inhibiting silica overgrowth. The Pittman model has the best estimation accuracy (Radj2=0.968); the Winland, K-T and Dastidar models give reasonable estimations (Radj2>0.92); others have poor performance (Radj2<0.90). The error of the Winland model is caused by considering throats corresponding to the same saturation. The errors of the Purcell and Dastidar models are caused by over-emphasizing the importance of the small throats. The error of the K-T model is partly due to the rapid intrusion rate. The poor performance of the Swanson, Thomeer and W-A models is because the log-log intrusion curves are not hyperbola particularly at the beginning and ending sections.

Structural characterizations of zinc-copper silicate polymer (ZCSP) and its mechanisms of ozonation for removal of p-chloronitrobenzene in aqueous solution

Abstract Zinc-copper silicate polymer (ZCSP) was synthesized and characterized using X-ray diffraction (XRD), scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDX), and nitrogen adsorption-desorption. The micro and mesoporous sample had columnar crystals and was mainly composed of amorphous silica (AS), hydroxylated copper (HC) and hydroxylated zinc (HZ). The ZCSP samples had high BET surface areas, high pore volumes and wide pore size distribution. The catalytic activity of ZCSP was investigated in terms of p-chloronitrobenzene (pCNB) and TOC removal. In the ozone/ZCSP process, 99.3% conversion of pCNB and 51.2% TOC were achieved in 15 min, respectively. The presence of tert-butanol (TBA) inhibited the degradation of pCNB in the ozone/ZCSP process and verified that the hydroxyl radicals ( OH) derived from ozone decomposition improved catalytic ozonation. The mechanism explaining the formation of OH on ZCSP surface was proposed. The HZ and HC composite had a positive impact on the oxidation affinity of pCNB. The zinc-copper oxide can act as Lewis acids and Brɵnsted bases to form surface hydroxyl groups. The hydroxyl groups were active sites that enhance ozone decomposition to form the OH. The ZCSP catalyst had good reusability and stability.

Photocatalytic Activity of Mesoporous Graphitic Carbon Nitride (mpg-C3N4) Towards Organic Chromophores Under UV and VIS Light Illumination

A template-assisted synthetic method including the thermal polycondensation of guanidine hydrochloride (GndCl) was utilized to synthesize highly-organized mesoporous graphitic carbon nitride (mpg-C3N4) photocatalysts. Comprehensive structural analysis of the mpg-C3N4 materials were performed by XPS, XRD, FT-IR, BET and solid-state NMR spectroscopy. Photocatalytic performance of the mpg-C3N4 materials was studied for the photodegradation of several dyes under visible and UV light illumination as a function of catalyst loading and the structure of mpg-C3N4 depending on the polycondensation temperature. Among all of the formerly reported performances in the literature (including the ones for Degussa P25 commercial benchmark), currently synthesized mpg-C3N4 photocatalysts exhibit a significantly superior visible light-induced photocatalytic activity towards rhodamine B (RhB) dye. Enhanced catalytic efficiency could be mainly attributed to the terminated polycondensation process, high specific surface area, and mesoporous structure with a wide pore size distribution.

Influence of catalyst pore network structure on the hysteresis of multiphase reactions

The effects of the catalyst pore network structure on multiphase reactions in catalyst pellets are investigated by using the experimentally validated pore network model proposed in our recent work (AIChE J, 62, 451, 2016). The simulations display hysteresis loops of the effectiveness factor. The hysteresis loop area becomes significantly larger, when having small volume‐averaged pore radius, wide pore‐size distribution, and low pore connectivity; however, the loop area is insensitive to pellet size, even though it affects the value of the effectiveness factor. The hysteresis loop area is also strongly affected by the spatial distribution of the pore size, in particular for a bimodal pore‐size distribution. The pore network structure directly influences mass transfer, capillary condensation, and pore blocking, and subsequently passes these influences on to the hysteresis loop of the effectiveness factor. Recognizing these effects is essential when designing porous catalysts for multiphase reaction processes. © 2016 American Institute of Chemical Engineers AIChE J, 63: 78–86, 2017

Electrospinning Fabrication and Enhanced Performance of 3D Li3V2(PO4)3/C Fiber Membrane as Self-standing Cathodes for Li-ion Battery

A three-dimentional(3D) long-range networking Li3V2(PO4)3/C fiber membrane was fabricated by a modified electrospinning method and a hot-press calcination process. The combined use of polyacrylonitrile (PAN) and polyvinylpyrrolidone (PVP) promotes the growth of Li3V2(PO4)3 crystals on the surface of the conductive carbon fibers. The adopted hot-press process is favorable to achieve a flexible 3D long-range networks. The Li3V2(PO4)3/C fiber membrane calcined at 800°C for 20h with a high specific surface area of 186.4m2/g and a wide pore size distribution can be used as self-standing, binder-free cathodes and exhibits excellent electrochemical performances. The discharge capacity is up to 196.8, 150.4 and 145.2 mAh/g at the current density of 0.1C, 5C and 10C, respectively. After the rate tests, the Li3V2(PO4)3/C fiber membrane cathode still exhibits an excellent cycle stability at 5C with a discharge capacity of 143.4 mAh/g after 850 cycles. These high performances are ascribed to the enhanced electronic and ionic conductivities owing to the 3D long-range conductive networks, well-crystallized Li3V2(PO4)3 particles in-situ grown on the surface of carbon fibers and the novel binder-free, self-standing structural characterics.

Multiscale pore‐network representation of heterogeneous carbonate rocks

AbstractA multiscale network integration approach introduced by Jiang et al. (2013) is used to generate a representative pore‐network for a carbonate rock with a pore size distribution across several orders of magnitude. We predict the macroscopic flow parameters of the rock utilising (i) 3‐D images captured by X‐ray computed microtomography and (ii) pore‐network flow simulations. To capture the multiscale pore size distribution of the rock, we imaged four different rock samples at different resolutions and integrated the data to produce a pore‐network model that combines information at several length‐scales that cannot be recovered from a single tomographic image. A workflow for selection of the number and length‐scale of the required input networks for the network integration process, as well as fine tuning the model parameters is presented. Mercury injection capillary‐pressure data were used to evaluate independently the multiscale networks. We explore single‐scale, two‐scale, and three‐scale network models and discuss their representativeness by comparing simulated capillary‐pressure versus saturation curves with laboratory measurements. We demonstrate that for carbonate rocks with wide pore size distributions, it may be required to integrate networks extracted from two or three discrete tomographic data sets in order to simulate macroscopic flow parameters.

Pressure pulse-decay tests in a dual-continuum medium: Late-time behavior

The pressure pulse-decay test has been one of the most widely used techniques to measure permeability for low-permeability rocks including shale, largely because relatively simple analytical solutions to fluid flow in a rock sample (characterized as a single continuum) exist for analyzing late-time test data. This work develops a new analytical solution for analyzing late-time pulse-decay test data for dual-continuum rock samples, motivated by the possibility that shale matrix (not including fractures) may exhibit dual- or multiple-continuum gas-flow behavior owing to its wide spread pore size distributions and property differences between organic and inorganic components of the shale matrix. This issue has important implications for characterizing and modeling gas flow in shale, because a dual-continuum medium involves more flow parameters and requires more complex modeling approaches than a single-continuum medium. Our new analytical solution shows that the relationship between gas pressure measurements from a pulse-decay test and permeability remains the same for both single- and dual-continuum systems, suggesting that shale-matrix permeability data in the literature, previously obtained from pulse-decay tests, are valid although the corresponding shale samples ought to be treated as dual-continuum instead of a single continuum system. In addition, our analytical solution relates mass transfer (between the two continua) to pressure change during late-time of a test. This relationship, with a clear and intuitive physical interpretation rooted in the mass balance principle, provides a simple and practical analysis technique to identify dual-continuum behavior from pulse-decay test data and to estimate mass transfer coefficient between the two continua if the dual-continuum behavior exists. The usefulness of the analytical solution is demonstrated by satisfactory matches with several pulse-decay test data sets. The data analysis results also indicate that not all shale samples exhibit dual-continuum gas-flow behavior regardless of their make-up and complex pore structures.

One-step synthesis of hierarchically porous carbons for high-performance electric double layer supercapacitors

With plenty of unique porous structure at micro-/nano scale, hierarchically porous carbons (HPCs) are promising for usage in advanced electric double layer supercapacitors (EDLCs) as the electrode materials. However, wide-range adoption of HPC for practical application is largely shadowed by its extremely complex synthesis process with considerably low production efficiency. Herein we reported a simple template-free, one-step sintering method, to massively produce the HPCs for high-performance EDLCs. Resorting to the 3D structure modification of the wide pore size distribution, high surface area of HPCs (up to 3000 m2 g−1) was achieved. By using 1 M Na2SO4 as electrolyte, the as-fabricated HPCs based EDLCs can be operated reversibly over a wide voltage window of 1.6 V with superior specific capacitance of 240 F g−1 under a current density of 0.5 A g−1. In the meanwhile, the EDLCs exhibit excellent rate capability (high power density of 16 kW kg−1 at 10.2 Wh kg−1) and long-term cycling stability with 9% loss of its initial capacitance after 2000 cycles. This output performance distinguished itself among most of the carbon-based EDLCs with neutral aqueous electrolyte. Thus, the template-free one-step sintering method produced HPCs for EDLCs represents a new approach for high-performance energy storage.

Modification of Commercial Activated Carbons for CO2Adsorption

The aim of the investigations was a modification of DTO, a commercial activated carbon (AC), to improve CO2 adsorption capacity. The adsorption of CO2 up to 40 bar at 40 ◦C temperature was investigated. The volumetric method was applied for CO2 adsorption isotherm measurements. The starting material — DTO — was modified using chemical activation (KOH, ZnCl2, K2CO3). The textural parameters of all the ACs were determined by nitrogen adsorption at the liquid nitrogen temperature of –196 ◦C on Quadrasorb SI. Results showed that the AC modified with KOH had the highest SBET, Vtot, Vmic values of 2063 m/g, 1.13 cm/g, and 0.67 cm/g, respectively. ACs with a wider pore size distribution (from micropores to mesopores) were obtained. The maximum CO2 adsorption was equal to 14.44 mmol/g for DTO/KOH — modified carbon whereas 8.07 mmol/g of CO2 was adsorbed at DTO. The CO2 adsorption capacities of the ACs were found to be closely correlated with the BET surface areas of the materials tested. The experimental data was fitted to the Freundlich, Langmuir, Sips and Toth equations to determine the model isotherm. The Sips model was found to be the best for fitting the adsorption of CO2.

Experimental study on the pore structure characteristics of tight sandstone reservoirs in Upper Triassic Ordos Basin China

Tight sandstone reservoirs typically show a wide pore size distribution, which ranges from several nanometers to several hundred micrometers, requiring a combination of several techniques to properly characterize the pore structure characteristics. In this article, scanning electron microscopy, nitrogen gas adsorption, pressure-controlled porosimetry, and rate-controlled porosimetry were applied to investigate the pore systems of five tight samples of Yanchang Formation in Upper Triassic Ordos Basin China. Pore throat types and shapes were qualitatively identified and classified by scanning electron microscopy and nitrogen gas adsorption, and pore size distribution was calculated by combination of nitrogen gas adsorption, pressure-controlled porosimetry, and rate-controlled porosimetry, which is proposed as a new method to obtain the overall pore structure characteristics of tight sandstone reservoirs; then analyzing microscopic pore structure controls of permeability stress sensitivity of tight sandstone reservoirs. Results indicate that three typical pore types exist in tight sandstone reservoirs, which are interparticle pores, grain dissolution pores and micro cracks, and pore shapes contain sheet and bent sheet, cylindrical, and bottle neck shapes. Pore size distribution develops from nano-micrometer scale completely in tight sandstone reservoir, nitrogen adsorption experiments can accurately characterize nanometer scale pore size distribution mainly ranging 2–50 nm; nano-micrometer scale pore throats distribution characteristics are quantitatively analyzed by pressure-controlled porosimetry and rate-controlled porosimetry, pore throats radius ranges 10 nm–40 µm using the former, pores radius ranges mainly 80–300 µm, throats radius ranges 100 nm–5 µm and pore throat ratio difference is bigger by the latter, and the pore throat structures determine the typical reservoir characteristics in Ordos basin. The emphasis of study on mechanism of permeability stress sensitivity currently is microscopic pore throat structures instead of macroscopic permeability, indicating that the strongest is micro cracks and neck pores, intergranular cylindrical pores and intragranular dissolution pores is the weakest. This is significant to the development of tight sandstone reservoirs.

Microsphere LiFe0.5Mn0.5PO4/C composite as high rate and long-life cathode material for lithium-ion battery

LiFe0.5Mn0.5PO4/C composite material (denoted as SP-LFMP/C) with macro/nano hierarchical porous structure by adding the composite carbon source (i.e., 100 nm polystyrene sphere and 300 nm carbon sphere) is fabricated via a spray dry process. The SP-LFMP/C composite exhibits a 3D hierarchical structure with a high surface area (34.63 m2 g−1) and a wide pore size distribution (2–100 nm). The characteristic properties of the samples are examined using X-ray diffraction, micro-Raman spectroscopy, scanning electron microscopy, high-resolution transmission electron microscopy, electrochemical impedance spectroscopy, and galvanostatic charge–discharge tests. The SP-LFMP/C composite achieves discharge capacities of 161, 160, 157, 146, 137, and 115 mAh g−1 at 0.2, 0.5, 1, 3, 5, and 10 C, respectively. Moreover, the SP-LFMP/C material also exhibits excellent cycling performance and stability at 55 °C during the 300 cycle test. These results indicate that the SP-LFMP/C cathode material is an excellent candidate for application in high-energy Li-ion batteries.

Adsorption Equilibrium of CO2 and CH4 and Their Mixture on Sichuan Basin Shale

Adsorption equilibrium isotherms of CO2, CH4, and mixtures of CO2/CH4 on shale sampled from Nanchuan, southeastern Sichuan Basin, were measured at 278, 298, and 318 K by an accurate gravimetric method. The adsorption equilibrium data of CO2 and CH4 were fitted using both the virial model and the Brunauer–Emmett–Teller (BET) model, and the isotherms of CO2/CH4 mixtures were fitted by an extended BET model. On the basis of adsorption data, the adsorption selectivity factors for CO2 over CH4 (αCO2/CH4) and thermodynamic parameters were estimated. Nanchuan shale was characterized with a high total organic carbon (TOC), having inorganic minerals and wide pore size distribution ranges. The adsorption heat, negative Gibbs free energy change, and negative surface potential of CO2 are larger than those of CH4, and the entropy loss of CO2 is larger than that of CH4, suggesting that adsorbed CO2 is in a more highly ordered arrangement than CH4 on shale. αCO2/CH4 values at different temperatures are all larger than 2.5.

Creating mesopores in ZSM-48 zeolite by alkali treatment: Enhanced catalyst for hydroisomerization of hexadecane

ZSM-48 zeolites with various Si/Al ratios were hydrothermally synthesized in the H2N(CH2)6NH2 (HDA)-containing media. The obtained samples were highly crystallized with minor mixed phases as evidenced by X-ray powder diffraction (XRD). The alkaline treated ZSM-48 zeolites maintained its structure under different concentrations of NaOH aqueous solution. Micropores remained unchanged while mesopores with wide pore size distribution formed after the alkaline treatment. The surface area increased from 228 to 288m2/g. The Brönsted acid sites had little alteration while an obvious increase of Lewis acid sites was observed. The hydroisomerization of hexadecane was performed as the model reaction to test the effects of the alkali treatment. The conversion of hexadecane had almost no change, which was attributed to the preservation of the Brönsted acid sites. While high selectivity to iso-hexadecane with an improved iso to normal ratio of alkanes was due to the mesopore formation and improved diffusivity.

Effect of Fe-doped TiO2 photocatalysts on the degradation of acid orange 7

ABSTRACTThe purpose of the research was to determine the photocatalytic degradation efficiency of acid orange 7 (AO7) using 2 mol% Fe-doped TiO2 as photocatalysts under UV irradiation. Fe-doped TiO2 powder synthesized by solid-reaction technique reveals the average particle size of 0.91 μm, BET surface area of 11.6 m2/g, a wide pore-size distribution with the average pore diameter of 3.2 nm and pore volume of 0.035 cm3/g. Within the experiment, AO7 was prepared as a synthetic textile wastewater at the initial concentration of 34 mg/L along with using various doses of Fe-doped TiO2 photocatalysts. The results indicated that Fe-doped TiO2 with dose of 0.100 g in 100 mL of AO7 reached the highest removal efficiency about 88.7%.

Filter Paper Inspired Zinc Oxide Nanomaterials with High Photocatalytic Activity for Degradation of Methylene Orange

Nanometer-sized zinc oxide (ZnO) has been synthesized through sol-gel method with natural cellulose substance (commercial filter paper) as template. The structure of zinc oxide nanomaterial was characterized by nitrogen adsorption-desorption and XRD. The morphology was observed by SEM and TEM. The results show that the hexagonal wurtzite phase is actually the only crystal phase in the sample and the product faithfully inherits the hierarchical morphology and the complex network structure of the original filter paper, which is composed of many randomly intersecting zinc oxide microfibers and nanosheets with lots of close stacked particles adsorbed on the surface. Moreover, these zinc oxide nanomaterials possess abundant mesoporous structure with an average pore diameter ofca. 21 nm and a wide pore size distribution (3–30 nm). Due to the strong absorption ability in the UV range, the zinc oxide nanomaterial prepared by this method displays significantly high photocatalytic activity for degrading methyl orange. In a short period of 20 minutes, the zinc oxide nanomaterial has degraded about 50% of the original MO, and the MO dye is fully degraded after UV irradiation for 80 minutes.

Generalized Model of Adsorption Equilibria Prediction for CO&lt;sub&gt;2&lt;/sub&gt; on Carbonaceous Adsorbents

The carbon molecular sieve CMS-200 and activated carbon Yigao-A have been adopted as adsorbents for the study of CO2 adsorption capture. The pore size distributions of both adsorbents were characterized by the modified H-K method. Adsorption isotherms of CO2 on the carbon molecular sieve CMS-200 and activated carbon Yigao-A were measured by the gravimetric method (Hiden, IGA-001) in the temperature region of 253.15-393.15 K and pressure region of 0-2 MPa. The Henry’s law constants of adsorption equilibria for CO2 were estimated using the Virial equation. The Ruthven’s generalized model was applied to analyze the experimental data on the basis of the values of the Henry’s law constants. The investigation demonstrates that the Ruthven’s generalized model not only is useful to describe the adsorption equilibria for CO2 on non-porous homogeneous carbonaceous adsorbents in the subcritical region, but also is reliable to predict the adsorption equilibrium data for CO2 on carbonaceous adsorbents with the uniform pore size distribution and the wide pore size distribution from the subcritical region to the supercritical region.