Understanding the Selective Adsorption of Phenol From Simple Mixture to Model Biofuel. Contribution of ATR‐IR Spectroscopy

Manipulating membrane surface porosity and pore size by in-situ assembly of Pluronic F127 and tannin

A significant breakthrough has been made in the preparation of 2D materials with controlled surface functionality, tailored pore structure and size over the last two decades. The development of advanced 2D nanomaterials has resulted in challenges in the area of physical adsorption characterization, and a broad textural characterization is critical for the optimization of 2D materials investigated in a variety of potential applications. As a matter of fact, specific surface area and pore size are decisive properties in the field of energy storage, catalysis, batteries, and several others. A thorough examination of the pore architecture and surface area is specifically vital because they influence diffusion rates, transport phenomena, rule selectivity, and performance in catalyzed reactions. This chapter discusses major aspects of underlying mechanisms of the most commonly used BET method for evaluating the surface area and pore size of porous and finely divided 2D nanomaterials. We discuss multiple examples of state-of-the-art specific surface area and pore size determination as well as a brief overview of the current challenges in physical adsorption analysis.

Study on the Pore Structure of Oil Shale During Low-Temperature Pyrolysis

Effect of crystals size, surface area, pore size and porosity of hydroxyapatite microspheres on the loading ability of bovine serum albumin was studied in this paper. The surface morphology, specific surface area and porosity of hydroxyapatite microspheres were characterized by scanning electron microscope, specific surface area and pore size analyzer, respectively. The concentration of BSA in aqueous solutions both before and after adsorption was determined by ultraviolet-visible spectrophotometer. The results indicated that the adsorption behavior of bovine serum albumin appeared to obey the Langmuir-type isotherm model. Fast adsorption appeared at the beginning, and then decreased gradually. Hydroxyapatite microspheres calcined at 600°C had the maximum capacity, and those calcined at 800°C showed lower adsorption ability. The loading ability of hydroxyapatite microspheres depended on its crystal size, specific surface area, pore size and porosity, etc.

Effects of foam cathode electrode structure on alkaline water electrolysis for hydrogen production

ABSTRACTSmall-angle scattering techniques have been used in a number of studies to characterize pore evolution in ceramic compacts. Parameters characterizing the pore distribution, such as total pore surface area, pore size, and pore density, have been measured through both intermediate and final stage sintering. A review of these results indicates that pore sizes were generally found to remain constant during intermediate-stage sintering; supporting a topological decay model of sintering. Pore sizes generally increased and the size distribution broadened during final-stage sintering. The scattering results also suggest the presence of a unique pore surface area versus density curve.

Purpose. The research was aimed to determine the dependence of the specific surface area and pore size distribution on the synthesis temperature for nanoporous carbon obtained from titanium carbide by chlorine treatment. Methodology. Nanoporous carbon has been obtained by treating titanium carbide powder with a stream of chlorine in a flow-type experimental setup at temperature range from 300°C to 1 200 °C. The specific surface area and pore size have been determined using automatic equipment (Quantachrome, USA) with computer control and data processing. To determine the specific surface, the Brunauer – Emmett – Teller (BET) method has been used. The porous structure of carbon, namely the pore volume and its size distribution, has been determined on the basis of the non-local density functional theory (NLDFT) using the software which is supplied with the device. Results . It has been experimentally established that change of chlorination temperature at titanium carbide processing effects on the pore size of the resulting carbon and allows controlling the same pore size in a narrow size range. With increasing temperature, the total pore volume and specific surface area increase as well and reach their maximum value at a synthesis temperature of 1 000 ° C (up to 1 442 m 2 /g according to BET), while the number of micropores decreases and mesoporosity increases. Scientific novelty . It has been found for the first time that due to a change in the temperature of titanium carbide chlorination it is possible to obtain nanoporous carbon with a controlled pore size up to 2 nm. Practical significance . The research results can be used for developing technology of supercapacitor production.

A honeycomb rotary wheel fabricated from sheet adsorbent of silica gel is a competitive drying facility for air dehumidification in modern drying and air conditioning industries due to its large contacting area (3,000 m2/m3) and the rapid diffusion of the adsorbate compared to silica gel pellets. The delicate preparation procedure of hygroscopic silica gel is paramount for improved adsorption capacity by optimizing the surface area, pore size, and pore volume of silica gel. In this article, silica gel adsorbent in a honeycomb rotary wheel was fabricated by neutralizing the impregnated water glass solution with a modulus of 3.3 on the glass fiber sheet of the honeycomb matrix using CO2 at different pressure at room temperature instead of corrosive acids. The as-obtained silica gel absorbent was characterized by XRD, scanning electron microscopy (SEM), specific surface area and pore size analysis, and dynamic vapor/gas sorption analysis. The results showed that the as-obtained silica gel adsorbent is uniform in size and tunable in terms of specific surface area, pore size, pore volume, and adsorption capacity by CO2 pressure. The typical silica gel fabricated by CO2 of 0.25 MPa with a specific surface area of 764.86 m2/g, an average micropore size with a diameter of 2.94 nm, and a pore volume of 0.45 ml/g delivers a saturated adsorption capacity of as high as 287.24 mg/g at RH 50%, which is the best in adsorption performance compared to the previously reported results. This provides a new strategy for environment-friendly manufacturing of silica gel adsorbent in honeycomb rotary wheels for air dehumidification.

The evolution of the microstructure of the wastepaper sludge ash-based dry-mortar mixtures is characterized. Mixtures have been prepared with a large volume of wastepaper sludge ash (WSA) and ground granulated blast-furnace slag (GGBS) as a binder matrix mixed with water. Two ratios of water/binder (w/b) = 0.5 and 0.6 were selected. Both of these two industrial by-products are well-known as supplementary cementitious materials in the construction industry and they constitute a convenient replacement for cement. A series of these dry mortars for two ratios w/b were activated by three different chemical activators. They were placed in 4 × 4 × 16 cm3 molds and then compacted at the same compaction energy of 600 kN·m/m3. The influence of water quantity, compaction level and activators on the microstructure of these mortars was investigated by measuring the specific surface area, pore size and volume. Different series of samples have been compared in terms of adsorption/desorption hysteresis and pores network. The influences of water quantity and energy level were first discussed on non-activated dry mortars and this analysis led to the selection of an optimal energy for the comparative study of activated dry mortars. A significant difference in behavior was observed between the studied activators in terms of specific surface area, adsorption property and pore distribution. Then, the microstructure of the three activated dry mortars is observed and analyzed considering the two w/b ratios, the mechanical strength obtained and the type and dosage of activator used. Dry mortars show micropores regardless the quantity of water and the dosage of activator.

Computer-generated mesoporous materials and associated structural characterization

Ionic liquid-assisted synthesis of triazine covalent organic frameworks for selective enrichment and sensitive detection of nonsteroidal anti-inflammatory drugs in urine and river water.

The effect of pore size on the gaseous adsorption of ethenzamide (EZ) on porous crystalline cellulose (PCC) in a mixture of PCC-EZ, and the physicochemical stability of EZ in a mixture of PCC-EZ after storage at various relative humidities (RHs) were investigated by powder X-ray diffractometry, differential scanning calorimetry, specific surface area and pore size distribution measurements. After heating a mixture of PCC-EZ, which contained less than 7% EZ, at 70°C at reduced pressure, the EZ became amorphous. The specific surface areas and pore size distribution curves of PCC and the heated mixtures of PCC-EZ were calculated from the nitrogen gas adsorption isotherms. The specific surface area of PCC was 82.3m2/g, while the specific surface areas of the heated mixtures of PCC-3% EZ, PCC-5% EZ and PCC-7% EZ were 74.1, 72.7 and 63.8m2/g, respectively. The specific surface area of the heated mixture of PCC-EZ decreased with an increase in the mixing ratio of EZ. In the pore size distribution curves of the heated mixtures of PCC-EZ, the pore volumes in the range of pore diameters from 2 to 40nm decreased compared with the pore volume of PCC. The volumes of pores with diameters ranging from 3 to 10nm decreased markedly with an increase in the mixing ratio of EZ. These results indicate that the adsorption of EZ on the pore surfaces of PCC occurred principally in the range of diameters from 3 to 10nm. After storage of the heated mixtures of PCC-7% EZ at various RHs for 7d at 30°C, recrystallization of EZ was observed in the X-ray diffraction spectrum when the mixtures were stored above RH 72.8% due to condensation of water vapor in pores.

In this study, phosphorus-modified alumina with large pore size was synthesized through a coprecipitation method. The carbon-covered, phosphorus-modified alumina with large pores was prepared by impregnating with glucose and carbonizing to further improve the adsorption of organic dyes. The morphology and structure of these composites were characterized by various analysis methods, and Rhodamine B (RhB) adsorption was also examined in aqueous media. The results showed that the specific surface area and pore size of the phosphorus-modified alumina sample AP7 (prepared with a P/Al molar ratio of 0.07) reached 496.2 m2·g−1 and 21.9 nm, while the specific surface area and pore size of the carbon-covered phosphorus-modified alumina sample CAP7–27 (prepared by using AP7 as a carrier for glucose at a glucose/Al molar ratio of 0.27) reached 435.3 m2·g−1 and 21.2 nm. The adsorption experiment of RhB revealed that CAP7–27 had not only an equilibrium adsorption capacity of 198 mg·g−1, but also an adsorption rate of 162.5 mg·g−1 in 5 min. These superior adsorption effects can be attributed to the similar pore structures of CAP7–27 with those of alumina and the specific properties with those of carbon materials. Finally, the kinetic properties of these composites were also studied, which were found to be consistent with a pseudo-second-order kinetic model and Langmuir model for isothermal adsorption analysis. This study indicates that the prepared nanomaterials are expected to be promising candidates for efficient adsorption of toxic dyes.

Mesoporous Ni/La2O3/γ-Al2O3 catalysts with different La contents (0, 0.5, 1.5, 2.5, 3.5, and 4.5 wt.%) were prepared by the step-by-step impregnation method. The physicochemical properties of the prepared Ni/La2O3/γ-Al2O3 catalysts were characterized by H2-TPR, XRD, BET, O2-TPO, and TG. The effect of La dosage on the catalytic performance of Ni/γ-Al2O3 catalyst for dry reforming of methane was further investigated. The results show that the La content has a significant effect on the reducibility of high-valence Ni species, specific surface area, pore size, and pore volume as well as the catalytic performances. The high-valence Ni species in the NL3.5A catalyst precursor has high reducibility. And the specific surface area, pore size and pore volume of the NL3.5A catalyst are 145.9 m2 g−1, 11.7 nm, and 0.47 cm3 g−1, respectively. The catalytic activity of the series of prepared mesoporous Ni/La2O3/γ-Al2O3 catalysts follows the order: NL3.5A > NL2.5A > NL4.5A > NL1.5A > NL0.5A > NL0A. Namely, the NL3.5A catalyst possesses the best catalytic activity. The CH4 and CO2 conversions of NL3.5A catalyst are 61.6 and 39.1% at 600 °C, respectively. Additionally, it maintains a superior recycle capability for dry reforming of methane reaction because of the high coke resistance compared with the Ni/γ-Al2O3 catalyst.

Amidst growing interest in renewable hydrogen gas production, this paper examines three important parameters affecting hydrogen production via formic acid decomposition reaction with nanoscale zero-valent iron (nZVI). The study investigates variations in nZVI dosage (200 – 1000 g/L), reaction temperature (25 – 75°C), and reaction time (5 -30 minutes) to identify optimum conditions for maximum hydrogen yield. Results indicate that the maximum hydrogen yield occurred at nZVI dosage, reaction temperature, and time of 800 g/L, 25°C and 30 minutes, respectively, yielding approximately 215 mL of hydrogen at optimal parameter values. The synthesized nZVI was also analysed before and after the reaction, focusing on the specific surface area and pore size of the nZVI. The results from BET characterization regarding specific surface area and pore size are consistent with experimental results, suggesting smaller pores correspond to higher surface area, enhancing reactivity with formic acid to produce hydrogen gas. Conversely, larger pore sizes after the reaction signify reduced surface area and lower reactivity of nZVI.