Rapid cycle pressure swing adsorption (RCPSA) characterized by short cycle time permits adsorbents to be used more frequently and increases process productivity. A rotary valve multi-bed RCPSA process is proposed to improve the performance of miniature oxygen concentrator. The RCPSA air separation system is highly integrated by four adsorbent beds and a rotary valve. The effects of process parameters

Enantioselective chromatography is nowadays a reliable tool for single enantiomer production from a racemate. The recovery of the distomer by racemization and recycling is a promising method to tackle the 50% yield constraint and to increase the productivity. In this paper three process configurations are compared. The production of enantiopure mandelic acid and methionine enantiomers exploiting different

Measurement of molecular diffusion in nanoporous host materials, which are typically inhomogeneous and anisotropic, often involves an intricate web of factors and relations to be taken into account since the associated diffusivities are a function of the diffusion path of the guest molecules during a given observation time. Depending on the observation time, therefore, the result of the experimental

The high conductivity of nanoprous carbons has a significant effect on adsorption of polar molecules; however, the mechanisms underlying this effect are not well-understood, and this effect is generally not considered in adsorption modeling. To investigate the impact of high host conductivity on the adsorption properties of vertical stacks of the graphene sheet, phenol vapor has been chosen as a simple

The adsorption of a methoxy radical (\(\hbox {OCH}_3\)) on the low-energy flat gold surfaces Au(111), Au(100) and Au(110) and on surface defects (adatoms) was compared with those of methanethiol (\(\hbox {SCH}_3\)) and methylamine (\(\hbox {NHCH}_3\)) radicals. Using dispersion-corrected DFT, we showed that the adsorption energy of \(\hbox {OCH}_3\) on gold is significantly lower than that of \(\hbox

In order to accomplish efficient CO2 capture, poly(ethyleneimine) (PEI) and tetraethylenepentamine (TEPA), with commonly used and inexpensive, was codispersed into the as-prepared SBA-15 (SBA-15(p)) to prepared blended amine functionalized adsorbent. The influence of the mass ratio of PEI to TEPA on the adsorption property was investigated. The promoting effects of TEPA on CO2 capture property were

A commercial gravimetric sorption analyzer, which is based on a magnetic-suspension balance, was significantly improved to reduce the uncertainty in adsorption measurements. In a previous paper, we investigated the force-transmission error (FTE) of the instrument’s magnetic-suspension coupling, and we analysed the uncertainty of the density measurement. In the present paper, equations for the determination

This paper analyses the effect of an adsorbed layer of variable curvature during the course of adsorption. To this end the capillary condensation and evaporation verified in pores endowed with elliptical geometry is studied. An adsorption potential within the pore walls is defined and it is numerically derived in accordance with the curvature of the pores and the attraction between the adsorbate and

A recently developed universal isotherm model was used in this work for the study of zirconium-added mesoporous silicas, focusing on the dehydration of low humidity gaseous streams. This modeling was chosen for its capability of calculating an energy distribution profile of the adsorption sites. This study was based on a systematic approach to evaluate three variables: the amount of zirconium substitution;

Abstract The adsorption of CO2 and CH4 on graphitic carbon nitride (g-C3N4) functionalized with four boron atoms (g-C43N4B4) were investigated by using the density functional theory for adsorption and separation of the CO2/CH gas molecules. The calculated Eads values showed that the CO2 molecule, in comparison with the CH4 molecule, has favorable interaction with the boron cluster hosted in the sheet

Abstract The determination and description of adsorption equilibria is critical for the design of several separation processes. In some instances, the dependence of the solid phase loading on the fluid phase concentration is complex and it is difficult to find a suitable functional form to represent the adsorption equilibria. This difficulty can be overcome by the use of discrete equilibrium data,

Abstract Activated carbon fibres with a range of pore sizes, prepared from pre-oxidized acrylic fibre by physical activation in CO2 at different temperatures and times, were investigated as adsorbents for the inhalation anaesthetic isoflurane (2-chloro-2-(difluoromethoxy)-1,1,1-trifluoroethane). Adsorption–desorption isotherms of isoflurane were determined at 293 K and were analysed by the αS method

Abstract Efficient and stable supercapacitor electrodes must possess large surface area, excellent conductivity and electrochemical stability. In this regard, conductive carbon loaded metal oxide composites are of particular interest. Herein, Ru–Mn oxide loaded graphene was synthesized with different graphene oxide (GO) proportion using simple solution chemistry method. Morphological and compositional

Abstract Solar energy is the most important type of modern and renewable energies. If it displaces fossil fuels, can bring an end to concerns about finiteness of fuels, environmental pollution caused by fossil fuels, price fluctuations and energy crisis. Among the energy sources, due to the high potential of solar energies in wide areas of the world, it has great importance to researchers. Dye-sensitized

Abstract Cu(II) anchored polymeric cryogels are synthesized for the isolation of B12. The poly(2-hydroxyethyl methacrylate) [poly(HEMA)] is used as solid support and N-methacryloyl-l-aspartic acid, is used as a ligand. Synthesis success is proved by the Fourier transform infrared spectroscopy, 1H and 13C nuclear magnetic resonance, scanning electron microscope, N2 adsorption method (Brunauer, Emmet

Abstract The adsorption and immersion of different fluids on a series of carbon molecular sieves was investigated. The carbon adsorbents with significantly different micro- and mesoporosity were characterized by means of nitrogen and argon adsorption at cryogenic temperatures, vapor adsorption at 298.15 K, liquid-immersion enthalpy and pH value measurements. The polarity and chain length of the fluid

Abstract The environmental fate and behavior of arsenic (As) is receiving increased attention due to the As pollution all over the world. Kaolinite is a natural mineral resource that can be used for the removal of pollution as adsorbent. First-principles calculations based on density-functional theory was employed to explore the adsorption behavior of arsenic atoms adsorption on the kaolinite (001)

Abstract The present study highlights performance of two adsorbents, namely aerocrete and vermiculite, modified with iron oxyhydroxide for removal As(V) from aqueous solution. A face-centered central composite design of response surface methodology (RSM) was employed to optimize efficacy of three experimental variables, adsorbent dosage, pH and initial As(V) concentration, and simultaneously the interactive

Abstract The adsorption of the Fe2+ and Fe3+ cations on four surface models of graphitic carbon nitride quantum dots, including planar and corrugated nanosheets of triazine and heptazine structures has been explored using density functional theory. The adsorption was most favorable on hollow sites but with different coordination numbers and geometrical configurations. A remarkable decrease in the energy

Abstract This work presents an activity-based formulation for Langmuir adsorption isotherm. Treating adsorption as a chemical reaction between the gas molecule and the adsorption vacant site, the classical Langmuir isotherm model expresses the reaction in terms of the species concentrations. Designed to capture the surface heterogeneity, the proposed thermodynamic Langmuir isotherm model substitutes

Abstract Microarrays play a determinant role in the detection and specification of biological molecules. The immobility of probe oligonucleotide with different sequences on the substrate surface is one of the main aims in designing of microarrays. In this regard, we select five different DNA single-strands to determine the best of probe single strand in the microarrays with a striped patterned double-layer

Abstract Isotherms of Ge(IV) and Cu(II) ions sorption on to the weakly basic anion-exchange resin AN-31 from chloride solutions have been constructed and described. The dependence of equilibrium parameters of Ge(IV) and Cu(II) ions sorption from chloride ions concentration was shown. Based on the electron spectra of diffuse reflectance of copper-containing sorbent, isotherms of sorption and isomolar

Abstract The theoretical calculations for the low-lying vibrational H atoms adsorbed on the Pt(110) surface are presented. We use the H/Pt(110) model with the conventional ultrahigh vacuum and the density functional theory to study the phonon frequency. The nature of hydrogen atoms, which were adsorbed on the four different sites of Pt(110) surface, is shown. The most stable site of the short bridge

Abstract The adsorption of CO and desorption of CO2 interacting with the Pt (111) surface was investigated using Kinetic Monte Carlo (kMC) simulation. The processes involved an elementary oxidation/reduction reaction (ORR). In comparison with standard density functional theory (DFT), kMC can simulate systems at practical time scale since it is concerned with the elementary reactions of the CO and O2

Abstract In the present work, we perform comprehensive theoretical calculations in order to examine interaction between Flutamide (FLU) anticancer drug and the nucleobases in the water and gaseous phases. The energetic, geometric and topological properties of Flutamide molecule interacting with four nucleotides bases, such as cytosine, thymine, uracil and guanine were studied from molecular point of

Abstract In the present study, an all-atomic molecular dynamic simulation was used to investigate adsorption of copper ions (Cu (II)) by carbon nanotube and hybrid graphene–carbon nanotube in aqueous solution. In order to study oxygenated functional groups effect including hydroxyl (–OH) and carboxyl (–COOH), these nano-structures were functionalized with OH and COOH groups. To this end, oxygenated

Abstract The comparative study of adsorption properties of several adsorbents with focus on selective isolation of water-soluble B vitamins (B2, B, B6 and B12) from food products and some pharmaceutical formulations by solid-phase extraction is performed. The adsorption of vitamins was investigated for eleven adsorbents including bare silica, silica modified with polyvinylpyrrolidone, octadecyl-, aminopropyl-

Abstract The pore size distribution (PSD) is an important property of the porous materials, but an accurate and reliable PSD is very difficult to obtain. Quenched Solid Density Functional Theory (QSDFT) is widely used to analyze the pore size distribution. Here, a series of unclosed and closed isotherms of activated carbon were measured and compared. The experimental results revealed the appearance

Abstract Elevated temperature pressure swing adsorption (ET-PSA) is a novel process for hydrogen purification. By operating steam rinse and purge at conditions beyond the dew point will significantly improve the recovery rate of the product gas. Moreover, since cooling and reheating processes are not needed in ET-PSA, the sensible heat of the incoming gas could also be preserved. In this study, a seven-column

h-BN monolayer as a novel 2D nanomaterial has raised great attention for sensing application in recent years. In this work, we using DFT method investigate the Pd-doping behavior on the pristine h-BN monolayer as well as related adsorption and sensing performance upon three SF6 decomposed species to explore its sensing potential. Our results indicate that n-typing doping is identified after Pd atom

Capillary condensation within the pore space formed by a hexagonal arrangement of carbon nanorods is investigated using a thermodynamic model. Numerical solution of the corresponding non-linear differential equations predicts two characteristic equilibrium phase transitions corresponding to liquid-bridge formation between adjacent rods, and the subsequent filling of the entire pore space with liquid

The first principles calculations were performed to study the adsorption of NO/NO2 molecules on carbon nanotubes (CNTs) doped with different number of aluminum atoms. Calculations show that upon the aluminum doping, the adsorption distance is decreased while the charge density, adsorption energy and charge transfer are increased dramatically, indicating that the adsorption of NO/NO2 on CNTs could be

MIL-88A metal-organic framework with the unsaturated Fe metal coordination sites has demonstrated to be a promising material for gas storage and capture. However, the hydrogen storage capacity of MIL-88A has to be improved to meet the practical level at the ambient conditions. In this research, we elucidated the effects of transition metal substitution on the hydrogen storage capability of MIL-88A

How to remove radionuclides from the radioactive wastewater quickly and efficiently is of great significance for mitigating the adverse effects of nuclear accident. Our previous researches have shown that metallic radionuclides (Cs+, Sr2+, and Ba2+) can be chemisorbed on monolayer 2H-MoS2. To enhance the adsorption capacity of the monolayer 2H-MoS2 to the metallic radionuclides, the effects of phase

Protein adsorption on solid state media is important for the industrial affinity chromatography of biotherapeutics and for preparing materials for self-interaction chromatography where fundamental protein solution thermodynamic properties are measured. The adsorption of three model proteins (lysozyme, catalase and BSA) and two antibodies (a monoclonal and a polyclonal antibody) have been investigated

This paper reports the results of an international interlaboratory study led by the National Institute of Standards and Technology (NIST) on the measurement of high-pressure surface excess carbon dioxide adsorption isotherms on NIST Reference Material RM 8852 (ammonium ZSM-5 zeolite), at 293.15 K (20 °C) from 1 kPa up to 4.5 MPa. Eleven laboratories participated in this exercise and, for the first

Measurement of the pore-size distribution (PSD) via gas adsorption and the so-called "kernel method" is a widely used characterization technique for rigid adsorbents. Yet, standard techniques and analytical equipment are not appropriate to characterize the emerging class of flexible adsorbents that deform in response to the stress imparted by an adsorbate gas, as the PSD is a characteristic of the