Internal Specific Surface Research Articles

Reaction Engineering Approach (REA) to Modeling Drying Problems: Recent Development and Implementations

Among the drying models available in the literature, the REA model (which was first proposed in 1996) is semi-empirical. It was described based upon a basic physical chemistry principle. The “extraction of water from moist material” is signified by applying the activation energy concept. The single expression of the extraction rate represents the competition between evaporation and condensation. It also encompasses the internal specific surface area and mass transfer coefficient, and thus is linked to material characteristics. The REA can be classified into two categories—Lumped (L) REA and Spatial (S) REA—which can be used to deal with drying a material as a whole or considering the local phenomena within the material, respectively. Both models have been proven to be very effective. The REA is effective for generating parameters since only one accurate drying run is required to establish the relative activation energy function. Both internal and external resistances are modeled by the REA. In its lumped format, the REA is employed to describe the global drying rate, while in the S-REA, the REA is used to model the local evaporation rate. This article covers fundamentals of the REA which have not been fully explained, as well as the most recent development and applications. The application of the S-REA as a non-equilibrium multiphase model is highlighted.

Evaluation of Swell Behavior of Expansive Clays from Internal Specific Surface and Pore Size Distribution

AbstractThe interdependency of microsoil fabric-related properties and swell/shrink behavior of expansive soils needs to be identified to achieve a more thorough and accurate prediction of heave of expansive soils. In a recent research study, two microsize-related properties of a soil—pore size distribution and specific surface area—were identified and examined in an effort to address their synergistic effects on swelling behavior of soils. To study this aspect in detail, eight natural expansive clayey soils from known expansive soil regions were sampled and studied by using two test methods: conventional one-dimensional vertical swell tests and novel three-dimensional volumetric swell strain tests. Microinternal structural details, including pore void distribution, were obtained from mercury intrusion porosimetry (MIP) studies on compacted soil specimens. Specific surface area (SSA) details of the same soils were determined using the chemical ethylene glycol monoethyl ether (EGME) method. Attempts were m...

X-Ray Refraction Techniques for Fast, High-Resolution Microstructure Characterization and Non-Destructive Testing of Lightweight Composites

X-ray refraction is based on optical deflection of X-rays, similar to the well-known small angle X-ray scattering, but hundreds of times more intense, thus enabling shorter measurement time. We show that X-ray refraction techniques are suitable for the detection of pores, cracks, and in general defects. Indeed, the deflected X-ray intensity is directly proportional to the internal specific surface (i.e., surface per unit volume) of the objects. Although single defects cannot be imaged, the presence of populations of those defects can be detected even if the defects have sizes in the nanometer range.We present several applications of X-ray refraction techniques to composite materials:- To visualize macro and microcracks in Ti-SiC metal matrix composites (MMC);- To correlate fatigue damage (fibre de-bonding) of carbon fibre reinforced plastics (CFRP) to X-ray refraction intensity;- To quantify the impact damage by spatially resolved single fibre de-bonding fraction as a function of impact energy in CFRP laminates.An example of classic high-resolution computer tomography of an impact-damaged CFRP will also be presented, as a benchmark to the present state-of-the-art imaging capabilities. It will be shown that while (absorption) tomography can well visualize and quantify delamination, X-ray refraction techniques directly yield (spatially resolved) quantitative information about fibre de-bonding, inaccessible to absorption tomography.

Anisotropic shaping of macroporous silicon

Various high-aspect structures fabricated from macroporous silicon with an ordered lattice by additional treatment in anisotropic etchants are considered. The conditions and specific features of the fabrication of structures with walls formed by a single type of slow-etched (110) or (100) planes and the dependence of their porosity and specific internal surface area on the wall thickness are determined. Zigzag, grid-like, and pillar-shaped structures fabricated on the basis of macroporous silicon by anisotropic treatment in aqueous KOH solutions are experimentally demonstrated.

Effect of the Size and Position of Ion-Accessible Nanoholes on the Specific Capacitance of Single-Walled Carbon Nanohorns for Supercapacitor Applications

We explore the importance of the size and position of nanoholes on the electrochemical performance of single-walled carbon nanohorn (SWCNH)-based supercapacitors using an ionic liquid electrolyte. The oxidized sample at 673 K showed a low specific capacitance per unit of internal specific surface area (4.0 μF cm–2), as the nanoholes created on the tips of SWCNHs via a selective chemical attack are too small to introduce electrolyte ions. For a sample oxidized at 723 K, the enlarged diameter of the nanoholes on the tips allows electrolyte ions to penetrate into the internal spaces of the SWCNHs, thereby resulting in a 2-fold capacitance improvement (8.6 μF cm–2). However, the abrupt decrease in the capacitance of the oxidized SWCNHs at 823 K (3.8 μF cm–2) can be explained by the selective formation of nanoholes on the sidewalls of the SWCNHs, where the small interstitial pores restrict ion diffusion to deeply positioned nanoholes on the sidewalls of the SWCNHs. Our study clearly reveals that the size and p...

Petrophysical Modelling For the Bahariya Formation, Egypt

Lithologic laminations have great consequences on the Bahariya sandstone, which are distinguished by the calculated reservoir statistical parameters. The non-laminated Bahariya studied samples have the lowest mean bulk density and specific internal surface values, while they have the highest mean porosity, permeability and Spor values. On the other hand, the laminated samples exhibit high values. The non-laminated Bahariya samples have the lowest mean permeability anisotropy, due to its relative pore-framework homogeneity. Contrary, the laminated Bahariya samples have the highest mean permeability anisotropy. By the same behaviour, the non-laminated Bahariya samples have the highest mean electrical resistivity value, due to the lack of conductive minerals, while the laminated Bahariya samples have the highest mean electrical resistivity.The non-laminated Bahariya samples show the lowest mean magnetic susceptibility value, while the laminated samples reveal high values. Sonic wave velocities (Vp and Vs) are statistically treated, while the velocity anisotropy is calculated for all samples. Laminated samples display higher velocity in comparable to the non-laminated ones. Thin sections and SEM-micrographs were made for some selected samples in order to recognize the Bahariya sandstone forming minerals. Glauconite, micas, zircon, rutile and pyrite minerals are composing the laminas in the laminated samples, while some glauconitic sandstone are predominant in the non-laminated ones.A number of linear regression models were performed among some measured petrophysical parameters, in order to differentiate between the laminated and the non-laminated sandstones, and to obtain reliable relationships permitting reservoir characterization.

Characterizing compression wood formed in radiata pine branches

The formation of reaction wood is an adaptive feature of trees in response to various mechanical forces. In gymnosperms, reaction wood consists of compression wood (CW) and opposite wood (OW) that are formed on the underside and upperside of bent trunks and branches. Although reaction wood formed in bent trunks has been extensively investigated, relatively little has been reported from conifer branches. In this study SilviScan® technology was used to characterize radiata pine branches at high resolution. Compared to OW formed in the branches, CW showed greater growth, darker colour, thicker tracheid walls, higher coarseness, larger microfibril angle (MFA), higher wood density, lower extensional stiffness and smaller internal specific surface area. However, tracheids of CW were similar to those of OW in their radial and tangential diameters. These results indicated that gravity influenced tracheid cell division and secondary wall formation but had limited impact on primary wall expansion. Furthermore, seasonal patterns of CW formation were not observed in the branches from cambial age 4 while earlywood and latewood were clearly separated in all rings of OW. The marked change of MFA during reaction wood formation suggested that branches could be ideal materials for further study of cellulose microfibril orientation.

Characterization of Shale Cap-Rock Nano-Pores in Geologic CO2 Containment

Research Article| November 01, 2014 Characterization of Shale Cap-Rock Nano-Pores in Geologic CO2 Containment ABIOLA OLABODE; ABIOLA OLABODE 1 Craft and Hawkins Department of Petroleum Engineering, Louisiana State University, 2129/2131 Patrick F. Taylor Hall, Baton Rouge, LA 70803 1Corresponding author email: aolabo2@lsu.edu. Tel.: 225-921-8309. Search for other works by this author on: GSW Google Scholar MILEVA RADONJIC MILEVA RADONJIC Craft and Hawkins Department of Petroleum Engineering, Louisiana State University, 2129/2131 Patrick F. Taylor Hall, Baton Rouge, LA 70803 Search for other works by this author on: GSW Google Scholar Environmental & Engineering Geoscience (2014) 20 (4): 361–370. https://doi.org/10.2113/gseegeosci.20.4.361 Article history first online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Search Site Citation ABIOLA OLABODE, MILEVA RADONJIC; Characterization of Shale Cap-Rock Nano-Pores in Geologic CO2 Containment. Environmental & Engineering Geoscience 2014;; 20 (4): 361–370. doi: https://doi.org/10.2113/gseegeosci.20.4.361 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyEnvironmental & Engineering Geoscience Search Advanced Search Abstract Clay-rich cap rocks such as shale should be investigated experimentally for their geomechanical and geochemical behavior when in contact with aqueous CO2 over a long period of time, as can be observed in geologic carbon sequestration. The reactivity of shale cap rock during diffusive transport of CO2-brine needs to be included in the reservoir characterization of potential CO2 sequestration sites because slow reactive transport processes can either strengthen or degrade seal integrity in the long term. This experimental work applied inductively coupled plasma–optical emission spectroscopy (ICP-OES) and the Brunauer-Emmett-Teller (BET) techniques in investigating changes in surface and near-surface properties of crushed shale rocks after exposure (by flooding) to CO2-brine for a time frame ranging from 30 days to 90 days at elevated pressure and fractional flow rate. Flooding of the shale samples with CO2-brine was followed by measurement of changes in internal specific surface area and linear pore-size distribution resulting from aqueous CO2 reactive transport. The intrinsically low hydraulic conductivity of shale may be altered by changes in surface properties because the effective permeability of any porous medium is largely a function of its global specific pore geometry and surface mineralogical properties. Capillary entry pressure for the shale, as well as the average pore throat size were estimated from digitally acquired pressure evolution data. This allowed for the estimation of dimensionless quantities such as Peclet (Pe) and Peclet-Damköhler (PeDa) numbers, which are associated with the geochemical reactivity of rocks and acidic fluid transport through porous media. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Hemicellulose, cellulose and lignin interactions on Arundo donax steam assisted pyrolysis

Slow Steam pyrolysis of Arundo donax is proposed as possible process for the recovery of a solid material suitable to be used as biochar. In view of the evaluation of the feasibility of such a process, products yields, surface area of char and energetic content of gaseous products needed to assist energetically the process are relevant data to be evaluated in dependence on process operating conditions and biomass characteristics. Biomass main components (hemicellulose, cellulose and lignin) contribute to a different extent to the determination of products yield and characteristics both for their own intrinsic chemical nature and for the onset of possible interactions due to their simultaneous presence in a real biomass. Moreover, it is known that inorganic elements present in the biomass can affect pyrolysis mechanisms and consequently products yields and characteristics. In the present paper the influence of inorganic species and of possible interactions between biomass main components on pyrolysis of A. donax has been studied. To this aim steam assisted pyrolysis tests have been carried out on a mixture of xylan, cellulose and lignin resembling the composition of A. donax canes in a proper experimental apparatus up to 873K, at pressure P=5×105Pa and heating rate HR=5K/min. Products yields, gas releasing rate as function of the temperature, gas composition and specific internal surface of char have been compared to the data computed from the superposition of the results obtained for the single components and to the behavior of untreated and demineralized samples of A. donax canes processed in the same experimental apparatus in the same operating conditions. Results obtained from this study show that primary pyrolysis of holocellulose is affected by the presence of inorganic species that depress the devolatilization of heavier compounds in favor of cracking reactions determining a higher release of light compounds, CO2 and CO. Moreover, interactions between lignin and cellulose are relevant in operating conditions where mass transfer phenomena cannot be neglected. Interesting results have been obtained for the solid residue as for the development of its internal surface that seems to be reduced from both interactions between biomass components and presence of inorganic ions.

Effects of Graphene in Graphene/TiO2 Composite Films Applied to Solar Cell Photoelectrode

A simple and effective method has been developed to prepare a composite porous film that incorporates graphene sheets and anatase TiO2 nanoparticles. After sensitization, the films have been investigated as dye-sensitized solar cell photoelectrodes. The cell performances showed that the incorporation of an optimized graphene content of 1.2 wt % increases the power conversion efficiency by 12% due to the enhancement of the short-circuit current density (Jsc). The photoelectrodes have been characterized by various techniques, and the cell functioning has been studied by impedance spectroscopy over a large applied potential range. The electronic structure, charge carrier lifetime (τn), transport/collection time (τtr), and electron transport parameters of the layers have been determined. We conclude that photoelectrodes with and without graphene show no limitation due to the transport of the I–/I3– redox shuttle. The rate of the charge transfer (recombination) parasitic reaction is unchanged with the presence of graphene. The electron transport in the photoelectrode is significantly faster for the composite film due to a quantified 60% increase in the layer conductivity. However, we have also shown that the charge-carrier collection efficiency is very high even without graphene, and that this parameter is not key to explain the cell-performance enhancement. Graphene also increases the film specific internal surface area. The composite films have a higher dye loading. They exhibit a better solar light absorption and a Jsc enlargement.

Anion and solvent responsive copolymeric gels – Morphology, annealing, and surfactant stimuli

The phase diagram of the pseudo-ternary aqueous 1-propanol (50:50 H2O:1-propanol by weight), ionic liquid acrylate, 1-(11-acryloyloxyundecyl)-3-methyl imidazolium tetrafluorborate (ILBF4), and methyl methacrylate (MMA) system is mapped for weight fractions of ILBF4 less than 0.75 at 25 °C and at 60 °C. The mapped region is composed of a very large single-phase microemulsion domain and an appreciable multi-phase (emulsion) domain. This emulsion domain shrinks in size with increasing temperature, in contrast to the homologous bromide system (ILBr) with an emulsion domain that is insensitive to temperature. Microemulsion polymerization of the 0.70/0.15/0.15 composition in this solvent/ILBF4/MMA system produces a solvogel that is further examined for its solvent and anion stimuli responsiveness. Aqueous-DMSO solvent exchange of the PF6− exchanged materials shows nearly reversible, but dissipative behavior on a macro-scale. Transformation of transparent gel to open cell porous material by anion exchange with PF6− is found to exhibit a (third) long time-scale behavior, wherein anion exchange is limited by ionic diffusion through condensed polymeric chains. The accompanying spinodal decomposition is also demonstrated to be driven by an amphiphilic anion, bis(2-ethylhexyl)sulfosuccinate, with interesting material effects to produce more pliable porous material than obtained by exchange with PF6−. Thermal and solvent annealing treatments show that these porous materials can be activated to lower their internal specific surface area, while retaining free volume available for stimuli-induced poration.

외부 및 내부 확산을 적용한 인도네시아 석탄촤의 연소 반응율 분석

본 연구의 목적은 국내 화력발전소에서 사용중인 인도네시아 석탄촤의 연소반응율을 연구하는 것이다. 석탄촤의 반응율은 External, Internal effectiveness factor를 고려하여 입자 내부 및 외부확산을 정량적으로 정리하였으며, Random pore model을 사용하여 탄소변환율에 따른 입자내부비표면적의 변화를 반영하였다. 가열 및 측정이 가능한 WHR(Wire Heating Reactor)를 활용하여 반응시간을 측정함으로써 석탄촤의 반응율을 도출하였고 BET(Brunauer-Emmett-Teller) 및 TGA(Thermo-Gravimetric Analysis) 장비를 활용하여 석탄촤의 물리적인 특성인 내부비표면적과 Random pore model의 구조변수(<TEX>${\Psi}$</TEX>)를 측정하였다. 석탄 종에 따른 활성화에너지 및 빈도인자를 도출하기 위해 아역청탄인 BARAMULTI, ENERGYMAN, AGM탄을 사용하였다. 본 연구 결과에서 External, Internal effectiveness factors를 통해 확산에 따른 kinetics를 비교한 결과 외부 확산 보다 내부 확산의 영향이 지배적임을 확인하였다. 최종적으로 내부 및 외부 확산에 대한 영향을 고려한 3종의 석탄촤 Intrinsic kinetics의 활성화에너지는 110~118 kJ/mol의 값을 보였다. The experiment was designed to compare the char combustion kinetics of pulverized Indonesia coals commonly utilized in Korea power plants. The reaction rate of coal char has been formulated using the external and internal effectiveness factors to describe the diffusion effect quantitatively. The Random Pore Model (RPM) was used for applying internal specific surface area as a function of carbon conversion ratio. Reaction rate was obtained from reaction time using the Wire Heating Reactor (WHR) which can heat and measure the char particle temperature at the same time. BET and TGA were used to obtain physical properties such as internal specific surface area and structural parameter. Three kinds of Indonesia Sub-bituminous coals "BARAMULTI, ENERGYMAN, AGM" were used in order to derive the activation energy and pre-exponential factor. The results of this study showed that the effect of internal diffusion than that of external diffusion is the dominant as comparison of kinetics was reflected in external and internal effectiveness factors. For three kinds of coal char, finally, activation energy of intrinsic kinetics indicates 110~118 kJ/mol.

A petrographic coded correlation between interface conductivity and other pore space properties

Electrical conductivity is an important property in geoscience and petroleum engineering. It gives not only information about the porosity and water saturation, but also about interfacial conductivity and about specific internal surface of the pore space. Archie’s equation correlates the electrical resistivity of a water-saturated rock sample and the resistivity of the pore water. A more detailed investigation with brine of different salinities results in the observation of interface conductivity, which is correlated to a specific internal surface. Measurements with increasing salinity of the brine were carried out on different samples: sandstone, carbonate and magmatic rocks. Additionally, permeability and effective porosity were determined. The resulting true formation factor and interfacial conductivity were then correlated with porosity and permeability. Analysis of data allows the application of the interface term as a measure of specific internal surface. For the interpretation of results, the simple capillary model a semi-empirical equation is used and delivers permeability as function of porosity, formation factor and interface conductivity. Determined permeability out of the calculations is compared with measured permeability. The developed equation which is dependent on the porosity, interface conductivity, formation factor and covers additionally the lithology influence can be used for a permeability calculation with a reasonable fit.

Specific features of the structural organization of composite fibrous membranes polycon and their electrotransport properties

Peculiarities of the porous structure and hydrophilic-hydrophobic properties of composite ion-exchange membranes Polycon K based on novolac phenolformaldehyde fibers are studied by the method of standard contact porosimetry. Differences are revealed in the values of maximum porosity, internal specific surface, volume of macropores, and other structural characteristics associated with different conditions of sulfonation of fibers. The formation of pores in the fibrous phase at the diffusion of monomers during the preparation of membranes is confirmed by the data of scanning electron microscopy and differential scanning calorimetry. Correlation is found between the structural characteristics and electrotransport properties of composite membranes. It is shown that the increase in the macropore volume in the modified fibers enhances the sensitivity of specific conductivity of membranes with respect to the concentration of equilibrium solution and leads to the lower selectivity.

Permeability prediction of four Egyptian sandstone formations

Reliable formation evaluation for oil and gas reservoirs or the modeling of groundwater flow requires accurate information on petrophysical properties such as permeability or porosity of the reservoir rocks. Porosity can be easily determined both in the laboratory and from well logs. Accurate experimental permeability determination requires more expensive methods. As an alternative, physical models and/or empirical equations have been proposed to enable permeability prediction based on more easily measurable parameters. This paper evaluates five models and formulae for permeability estimation based on petrophysical parameters that are related to pore space geometry. The fundamental parameters that are related to pore size or specific internal surface were determined by nitrogen adsorption, nuclear magnetic resonance, and spectral induced polarisation measurements. Petrophysical parameters of 96 sandstone samples from four sandstone formations in Egypt were included in this study. The comparison of the predictive quality of the models provides more insight into the limitations of the individual models. The roughness of the internal surface, the clay content, the connectivity of the pore space and the distribution of iron minerals are identified as the most relevant properties affecting the predictive quality of the models.

Effect of process parameters of manufacturing of composite fibrous membranes on their structure and ion selectivity

The porous structure of Polikon K composite ion-exchange membranes based on polyacrylonitrile fibers has been studied by standard contact porosimetry. Differences in maximum porosity, internal specific surface area, macropore volume, and other structural characteristics attributed to the use of different molding pressures during the preparation of the membranes have been revealed. According to the analysis of the porometric curves measured in octane and water, it has been found that the volume of hydrophobic pores in the Polikon membranes is an order of magnitude lower than the total volume of hydrophilic pores. The ion selectivity of the membrane materials has been estimated from the porometric curves. A comparison of the ion transport numbers measured by the potentiometric method to the calculated values has shown that they are in good agreement.

X-Ray Analysis of Characteristic Features of the Heterogeneity of Cellulose Fibers When Interacting With Water

UDC 539.264:677.03 We have developed a procedure for quantitative analysis of small-angle x-ray scattering by cellulose fibers swollen in water, enabling a comparative estimate of the interfacial surface area between the crystalline and amorphous phases and also the specific surface area of the crystallites. We show that the specific interfacial surface area between the crystallites and the swollen amorphous phase of the polymer practically remains unchanged on going from cotton to less crystalline mercerized and viscose rayon fibers. Mercerization of cotton fibers, under conditions ensuring complete transition of cellulose I to cellulose II, leads to an increase in the specific surface area of the crystallites by a factor of 1.4, suggesting a decrease in crystallite sizes and an increase in the amount of crystalline phase per unit weight in the polymer. Breakdown of the morphological structure of the natural cellulose material when obtaining viscose rayon fibers leads to formation of a system of crystallite formations, the specific surface area of which is 1.82 times greater than the analogous parameters for cotton. In order to estimate the reactivity of cellulose fibers, determining their specific internal surface area (SISA) is very important both in the dry state and when the fibers interact with water, i.e., under conditions approaching real dyeing and finishing processes. Comparative analysis of the specific surface area of cotton fibers from sorption of nitrogen and water vapor [1] has shown that the values of the indicated parameter determined in the first and second cases differ by tens of times (respectively 1.7 and 137.0 m 2 /g). In the author’s opinion, the observed phenomenon is due to a significant increase in micropore content in the cellulose during sorption of water vapor. In this case, by micropores we mean the space between the polymer macromolecules appearing during absorption of water by the fibers. Below the compatibility limit, water sorption occurs via the amorphous regions of the cellulose, with formation of a single-phase system in them [2-4]. The ability of the amorphous phase of cellulose to form a molecular dispersion with water, characterized by new packing of the polymer and water molecules, has been noted in [5, 6]. In this case, the water and the polymer lose their individual physical and chemical properties. Consequently, the SISA value of cellulose fibers calculated from water vapor sorption isotherms cannot be considered as reliable. A method based on analysis of the nature of small-angle x-ray scattering is also used to study the internal surface area of heterogeneous materials [7, 8]. Study of the internal surface area of cellulose fibers by small-angle x-ray scattering is complicated when a system with water is formed. Analysis of the factors determining the appearance of small-angle scattering for swollen fibers has been presented previously in [9, 10]. However, the lack of procedures for normalization of the diffraction parameters for a polymer — solvent system does not permit quantitative studies of the characteristic features of the SISA for swollen fibers. This study was devoted to solving the problems indicated above.

Silkworms’ feces-based activated carbons as cheap adsorbents for removal of cadmium and methylene blue from aqueous solutions

Activated carbon samples, ACs, were obtained from silkworms’ feces via chemical activation method. Many activating agents including the new ones KCl, CrCl3 and TiCl4 were compared. Acidic and basic oxidic groups in addition to aromatic tertiary and secondary amines have been detected on the surface of produced ACs. Furthermore, microporous solids furnishing high internal specific surface area, ranging between 1000 and 2000m2/g, and total pore volume up to 0.85cm3/g were obtained. TiCl4 resulted in the solid possessing the highest area and pore volume. The obtained solids showed high efficiency in removing methylene blue and cadmium from their aqueous solutions. Adsorption capacity of sample AC/TiCl4 is 461mg/g of MB at pH=10, and 62.6mg/g of Cd2+ at pH=8. The nature of the formed microporous texture and the prevailing surface oxidic groups are the main controlling parameters for the observed high efficiency toward both adsorbates.

Evidence of Micropore Filling for Sorption of Nonpolar Organic Contaminants by Condensed Organic Matter

Although microporosity and surface area of natural organic matter (NOM) are crucial for mechanistic evaluation of the sorption process for nonpolar organic contaminants (NOCs), they have been underestimated by the N adsorption technique. We investigated the CO-derived internal hydrophobic microporosity () and specific surface area (SSA) obtained on dry samples and related them to sorption behaviors of NOCs in water for a wide range of condensed NOM samples. The is obtained from the total CO-derived microporosity by subtracting out the contribution of the outer surfaces of minerals and NOM using N adsorption-derived parameters. The correlation between or CO-SSA and fractional organic carbon content () is very significant, demonstrating that much of the microporosity is associated with internal NOM matrices. The average and CO-SSA are, respectively, 75.1 μL g organic carbon (OC) and 185 m g OC from the correlation analysis. The rigid aliphatic carbon significantly contributes to the microporosity of the Pahokee peat. A strong linear correlation is demonstrated between / and the OC-normalized sorption capacity at the liquid or subcooled liquid-state water solubility calculated via the Freundlich equation for each of four NOCs (phenanthrene, naphthalene, 1,3,5-trichlorobenzene, and 1,2-dichlorobenzene). We concluded that micropore filling ("adsorption") contributes to NOC sorption by condensed NOM, but the exact contribution requires knowing the relationship between the dry-state, CO-determined microporosity and the wet-state, NOC-available microporosity of the organic matter. The findings offer new clues for explaining the nonideal sorption behaviors of NOCs.

Positronium annihilation in LTA-type zeolite

Dehydrated polycrystalline powder of LTA-type zeolite and its pellets, prepared from 7.86×10−2 to 1.5728GPa, were studied by XRD, SEM, BET and PALS. Crystal size, texture and changes in the inter-particle pellet volume were observed from XRD and SEM results, respectively, as the pellet pressure increased. Positron lifetime spectra of these zeolite samples consisted of four lifetime components (τi, Ii; i=1, 2, 3, 4), remaining practically constant each lifetime (τi) as the pellet pressure was varied, but their intensities were pressure dependent. The decreasing tendency of the inter-particle pellet volume can be followed by the mean lifetime τ124+τ1*I1+τ2*I2+τ4*I4, where the third lifetime component was practically pellet pressure independent. The third and fourth lifetime components (τ3, I3; τ4, I4) can be assigned to o-Ps annihilating in the dehydrated β and α cages of the zeolite, respectively, as inferred from the correlation between the calculated specific internal surface area of the zeolite and that obtained from PALS data, registered either form the 50 or 800ns instrumental windows.