for Journals by Title or ISSN for Articles by Keywords help
 Subjects -> ENGINEERING (Total: 2358 journals)     - CHEMICAL ENGINEERING (201 journals)    - CIVIL ENGINEERING (192 journals)    - ELECTRICAL ENGINEERING (107 journals)    - ENGINEERING (1240 journals)    - ENGINEERING MECHANICS AND MATERIALS (394 journals)    - HYDRAULIC ENGINEERING (56 journals)    - INDUSTRIAL ENGINEERING (72 journals)    - MECHANICAL ENGINEERING (96 journals) ENGINEERING (1240 journals)                  1 2 3 4 5 6 7 | Last
 Adsorption   [SJR: 0.774]   [H-I: 52]   [4 followers]  Follow         Hybrid journal (It can contain Open Access articles)    ISSN (Print) 1572-8757 - ISSN (Online) 0929-5607    Published by Springer-Verlag  [2352 journals]
• Analysis of ideal sorption compressor cycles operating with gas mixtures
• Authors: N. Tzabar; H. J. M. ter Brake
Abstract: Sorption-based compressors are thermally driven and because of the absence of moving parts they are vibration free, and have the potential for long life. Sorption-based compressors have been reported to operate Joule–Thomson (JT) cryogenic coolers with pure working fluids. However, using mixed refrigerants instead of pure refrigerants is attractive since that would dramatically improve the system coefficient of performance. Our on-going research aims to develop an efficient JT sorption cryocooler, operating with mixed refrigerants, and is focused on studying the characteristics of the sorption compressor cycle. This paper presents the results of an advanced numerical analysis, which is based on a previous model, and its experimental verification. The analysis relates to the ideal cycle of a sorption compressor operating with a gas mixture. Obviously, dynamics and kinetics play a major rule in a real sorption compressor cycle. However, since there are no reported gas-mixture sorption compressors and the existing experience in this field is poor, a preliminary ideal cycle analysis is considered. Satisfying agreement between the numerical and experimental results is obtained and the processes in the sorption cycle are discussed. The outcomes of the current study are the basis for the next phase in which a sorption compressor prototype will be built operating with gas mixtures.
PubDate: 2018-02-26
DOI: 10.1007/s10450-018-9937-2

• Chloride adsorption on Fe- and Al-(hydr)oxide: estimation of Gibbs free
energies
• Authors: N. Y. Acelas; E. Flórez
Abstract: In this study, we used chemical quantum methods to analysis the adsorption of chloride on Al and Fe-(hydr)oxide clusters. Inner and outer sphere complexes were the generating complexes during the adsorption process on variably charged Al- and Fe-(hydr)oxide clusters. For the chloride adsorption on Al-(hydr)oxide, the outer sphere complexes—H-bonded—were favored for all clusters, while the adsorption modes as inner sphere complexes—BB or MM—were not favored. It was found, that the H-bonded complex on neutral clusters was the most thermodynamically favored with an adsorption energy of − 63.4 kJ/mol. For iron clusters, thermodynamic favorability was observed for both outer (− 70.5 kJ/mol) and inner monodentate (− 65.8 kJ/mol) sphere complexes. These theoretical results indicated that the thermodynamic favorability of chloride adsorption on Fe and Al-(hydr)oxide was directly related to positive surface charge.
PubDate: 2018-02-21
DOI: 10.1007/s10450-018-9939-0

• New hybrid composite honeycomb monolith with 13X zeolite and activated
carbon for CO 2 capture
• Authors: Maria João Regufe; Alexandre F. P. Ferreira; José Miguel Loureiro; Yixiang Shi; Alírio Rodrigues; Ana Mafalda Ribeiro
Abstract: Due to the industrialization, it is urgent to reduce the carbon dioxide emissions. For that, diverse technologies can be applied. In adsorption processes, the development of new materials is an emerging challenge in order to increase the CO2 adsorption capacity of materials and the efficiency of the processes. In this work, a new hybrid honeycomb monolith composed by zeolite and activated carbon was produced by extrusion process. Single adsorption equilibrium isotherms of carbon dioxide and nitrogen were measured by a gravimetric method using a Rubotherm® magnetic suspension balance at three temperatures, 303, 333 and 373 K. The experimental points were well described by Dual-Site Langmuir model. The material presented a carbon dioxide adsorption capacity of 2.63 mol kg−1 at 1 bar and 303 K. Binary breakthrough curves were obtained at 298 K and 2.4 bar with different feed mixtures. The experimental results of adsorption equilibrium were validated with the Dual-Site Langmuir isotherm extended to multicomponent mixtures. A mathematical model was applied to predict the dynamic behaviour of the adsorption bed.
PubDate: 2018-02-17
DOI: 10.1007/s10450-018-9938-1

• Characterization of hydroxylated amorphous silica: a numerical approach
• Authors: Nicholas W. Suek; Maxime C. Guillaume; Jean-Yves P. Delannoy; Frederik Tielens
Abstract: Hydroxylated amorphous silica nanoparticles were modeled using a combination of computational techniques at different levels of length scales from Ångström to hundreds of nanometers. Using quantum chemical ab initio methods, force field Monte Carlo methods, reactive force field simulations, and numerical model calculations, including BET theory calculations it was possible to describe and model the physico-chemical properties of hydroxylated amorphous silica. The results are compared with experimental data and found to be in good agreement with the theory, confirming the reliability of the computational method and the silica model structure.
PubDate: 2018-02-12
DOI: 10.1007/s10450-018-9936-3

• Adsorption/desorption of 2,2,4-trimethylpentane on MCM-36 zeolite
functionalized by acidic ionic liquid
• Authors: Yaling Li; Tao Zhang; Shengwei Tang
PubDate: 2018-01-30
DOI: 10.1007/s10450-018-9935-4

• Resorcinol–formaldehyde carbon xerogel as selective adsorbent of carbon
dioxide present on biogas
• Authors: Jose F. Vivo-Vilches; Agustín F. Pérez-Cadenas; Francisco J. Maldonado-Hódar; Francisco Carrasco-Marín; Maria J. Regufe; Ana M. Ribeiro; Alexandre F. P. Ferreira; Alirio E. Rodrigues
PubDate: 2018-01-23
DOI: 10.1007/s10450-018-9933-6

• Graphical approach for formulating pressure swing adsorption cycle
schedules with unlimited equalization steps
• Authors: Armin D. Ebner; Jason G. S. Ho; James A. Ritter
Abstract: A graphical unit block was used to formulate new PSA cycle schedules that include an unlimited number of equalization steps, no idle steps, no dead time and a minimum number of just three PSA beds assisted with two or more equalization tanks. The approach to designing these PSA cycle schedules is based on three simple rules: (1) restrict the placement of all the equalization steps within the boxes of the PSA cycle schedule to be in sequence with no other cycle steps in between them; (2) place all the equalization steps in the left most boxes of the PSA cycle schedule underneath the Bed 1 feed step with no other cycle steps below them except other equalization steps; and (3) add equalization tanks as needed. These new 3-bed PSA cycle schedules may include any of the common PSA cycle steps in such a way that the equalization steps do not interfere with any of the non-equalization steps affording the non-equalization steps additional degrees of freedom. Since a bed-to-tank-to-bed equalization step may not be as effective as a bed-to-bed equalization step, a forced cocurrent depressurization (CoD) step coupled with an intermediary light end pressurization (LEP) step can be added to this 3-bed PSA cycle schedule. These coupled steps take place after the last of the equalization down and up steps with the aid of a compressor or vacuum pump. Since the utilization of several equalization steps and the utilization of forced CoD/LEP steps may limit the duration of the countercurrent depressurization (CnD) and/or light reflux (LR) steps, one or more additional beds can also be added to this 3-bed PSA cycle schedule. These additional beds increase the durations of the CnD and LR steps without affecting the duration of the feed step. Any combination of these PSA cycle schedule improvements can be used to improve the PSA process performance in terms of capital and operating costs, productivity or throughput, and recovery and purity of the species of interest whether it is the heavier, lighter or both species.
PubDate: 2018-01-18
DOI: 10.1007/s10450-018-9934-5

• DFT study of the adsorption and dissociation of
5-hydroxy-3-butanedithiol-1,4-naphthaquinone (Jug-C4-thiol) on Au(111)
surface
• Authors: Karima Lassoued; Mahamadou Seydou; Fayçal Raouafi; Fadhel Larbi; Philippe Lang; Boubakar Diawara
Abstract: Density functional theory has been used to investigate the adsorption and dissociation of 5-hydroxy-3-hexanediol-1,4-naphthaquinone (Jug-C4-thiol) at a coverage of p(4 × 4) on a Au(111) surface. Both physisorption and chemisorption processes are investigated. For each process, the surface energy potential is explored by an exhaustive test of the adsorption site. The most favorable site is found to be face-centered cubic. The adsorption energies are less than − 0.20 eV in the case of physisorption, while they range from − 1.70 to − 1.92 eV for chemisorption. The effect of the naphthoquinone function is negligible in the adsorption process. The alkyl chain inhibits electron delocalization between the surface and the conjugated head of the molecule. Analysis of the bonding shows the formation of two ionocovalent bonds between the sulfur and the gold atoms. The thermodynamics and kinetics of S–H bond dissociation are studied. The results reveal that adsorption involves a dissociation path in which a hydrogen atom moves to the most neighboring site and a hydrogen atom migrates to its most stable site. The maximum barrier energy of the first step is less than 2.7 eV while the migration barrier does not exceed 0.5 eV.
PubDate: 2018-01-17
DOI: 10.1007/s10450-018-9932-7

• Towards polymer grade ethylene production with Cu-BTC: gas-phase SMB
versus PSA
• Authors: Vanessa F. D. Martins; Ana M. Ribeiro; Jong-San Chang; José M. Loureiro; Alexandre Ferreira; Alírio E. Rodrigues
Abstract: The recovery of ethylene as a product from ethylene/ethane mixtures by adsorptive processes has been attracting great interest due to the high operating and capital costs of the cryogenic distillation traditionally practiced. This search for novel economical ways to separate olefins from paraffins by adsorptive processes has motivated the appearance of improved materials. The trend of developing new materials, such as metal–organic frameworks (MOF) and the challenge of improving the existing technologies, such as pressure swing adsorption (PSA) and simulated moving bed (SMB) leave the horizon open for new alternatives. In the present work, PSA and SMB in gas phase were tested to produce ethylene at high purity on Cu-BTC MOF in beads form. For the first time, the olefin/paraffin separation by SMB technology, using a MOF as adsorbent, was achieved. Both technologies were successfully implemented experimentally and simulated. In the best cycle performed by VPSA for the 20/80 ethane/ethylene feed composition, the ethylene was obtained with a purity of 98.0% at a recovery of 70.2% and a productivity per unit mass of stationary phase of 1.55 molC2 h−1 kg−1adsorbent. Additionally, for the 50/50 ethane/ethylene mixture only 43.2% of the ethylene is recovered at a purity of 95.4% and a productivity of 0.52 molC2 h−1 kg−1adsorbent. In the two cycles performed by SMB, to separate 39/61 ethane/ethylene mixture, ethylene was obtained with a purity of 95%, a recovery above 90% and productivity between 0.50 and 0.66 molC2 h−1 kg−1adsorbent. All the experiments were well predicted by the axial dispersion flow model with the LDF approximation.
PubDate: 2018-01-05
DOI: 10.1007/s10450-017-9930-1

• Facile synthesis of magnetic hydroxyapatite-supported nickel oxide
nanocomposite and its dye adsorption characteristics
• Authors: Apakorn Phasuk; Suppachai Srisantitham; Thawatchai Tuntulani; Wipark Anutrasakda
Abstract: A novel magnetic hydroxyapatite-supported nickel oxide nanocomposite (NiO–HAP@γ-Fe2O3) was successfully prepared using a combination of co-precipitation and wet impregnation methods and was applied to the adsorption of methylene blue from aqueous solution. The presence of HAP, γ-Fe2O3, NiO and all elements in NiO–HAP@γ-Fe2O3 was confirmed by XRD, SEM–EDX and ICP-AES. The structure of the resulting nanocomposite was shown by TEM and SEM–EDX to be rod-shaped, measuring 55.8 ± 16.5 nm in length and 27.1 ± 6.2 nm in width, and on the surface of which was uniformly interspersed with NiO nanoparticles (about 21.4 nm average crystallite size) and γ-Fe2O3 nanoparticles (6.7 ± 2.6 nm in diameter). The novel NiO–HAP@γ-Fe2O3 exhibited a high adsorption rate during the first 20 min and reached an equilibrium within 3 h. The adsorption capacity of NiO–HAP@γ-Fe2O3 was significantly higher than that of its precursors (7.20 mg g−1 vs 0.79–1.31 mg g−1). The superior adsorption performance of the novel nanocomposite, which occurred despite its relatively low surface area, is likely attributable to the synergistic mechanisms facilitated by the presence of mixed metal oxides (NiO and γ-Fe2O3) on the adsorbent as well as by the Lewis acidity and basicity of the components of the adsorbent and the adsorbate. The adsorption kinetics and isotherms were well-fitted by the pseudo-second-order kinetic model and the Langmuir isotherm model, respectively.
PubDate: 2017-12-23
DOI: 10.1007/s10450-017-9931-0

• Chromium(VI) removal using in-situ nitrogenized activated carbon prepared
from Brewers’ spent grain
• Authors: S. R. H. Vanderheyden; K. Vanreppelen; J. Yperman; R. Carleer; S. Schreurs
Abstract: In-situ nitrogenised activated carbons (ACs) are prepared from brewers’ spent grain (BSG) using different activation procedures. Cr(VI) adsorption (10 mg/L, pH 2) on these ACs is compared to adsorption on commercial Norit GAC 1240 and Filtrasorb F400. The adsorption isotherms for both Cr(VI) and Cr total (Crtot) are determined for each AC, of which the best performing ones are chosen for kinetic experiments. The adsorption mechanism towards Cr(VI) is accompanied by its reduction to Cr(III), removing almost all Cr(VI) even at low dosages for all tested ACs. An optimal dosage (0.75 g/L) is found for each AC. For the best performing AC this dosage results in removal rates of over 99% of Cr(VI) and 88% of Crtot. The amount of reduced Cr(VI) increases with AC dosage, resulting in a higher Cr(III) equilibrium concentration above this optimal dosage. The redox reaction is more dominant in the commercial ACs. However, a faster removal rate for the ACBSGs for both Cr(VI) and Crtot is demonstrated.
PubDate: 2017-12-13
DOI: 10.1007/s10450-017-9929-7

• Efficient defluoridation of water by Monetite nanorods
• Authors: Junjie Shen; Marina Franchi Evangelista; Godfrey Mkongo; Haibao Wen; Richard Langford; Georgina Rosair; Martin R. S. McCoustra; Valeria Arrighi
PubDate: 2017-12-11
DOI: 10.1007/s10450-017-9928-8

• Chromium adsorption into a macroporous resin based on
vinylpyridine–divinylbenzene copolymers: thermodynamics, kinetics, and
process dynamic in a fixed bed column
• Authors: José Antonio Arcos-Casarrubias; Martín R. Cruz-Díaz; Judith Cardoso-Martínez; Jorge Vázquez-Arenas; Francisco Vidal Caballero-Domínguez
Abstract: The synthesis of the poly(4-vinylpyridine-co-ethylvinylbenzene) resin is investigated and its performance to remove Cr(VI) from aqueous solutions is evaluated as a function of pH using batch and fixed bed column adsorptions. The rate of Cr(VI) removal is observed to increase as the pH solution shifts to acidic conditions due to an enhanced protonation of the 4-vinylpyridine group in the polymer, which favors its electrostatic attraction with Cr(VI) oxyanions. This finding is supported with Density Functional Theory (DFT) calculations, revealing that the interaction between $${\text{CrO}}_{4}^{{2 - }}$$ (predominant species at pH < 6) and protonated 4VP is more favorable than a bond formed with $${\text{HCrO}}_{4}^{ - }$$ species (pH > 6) due to a higher charge delocalization arising in the O atoms. Experimental isotherms are approximated with the Langmuir and Radke-Prausnitz adsorption models. This former approach generates the best fitting to the data, whereby it was incorporated into a nonlinear transient model to account for the Cr(VI) adsorption in a fixed bed, and evaluating its capacity to predict experimental adsorption data. The model enables to infer that the resin presents a fast kinetic for Cr(VI) sorption, and the Cr(VI) intra-particle diffusion across the adsorbent pores is the rate-determining step for sorption.
PubDate: 2017-11-30
DOI: 10.1007/s10450-017-9925-y

• Oxygen sorption/desorption kinetics of SrCo 0.8 Fe 0.2 O 3−δ perovskite
adsorbent for high temperature air separation
• Authors: Peixuan Hao; Yixiang Shi; Shigang Li; Shuguang Liang
Abstract: Perovskites with high selectivity for oxygen are expected to be advantageous for oxygen production by vacuum pressure swing adsorption (VPSA). However, the kinetics of this process has only been investigated by thermogravimetric analysis (TGA) and fixed-bed setups, which cannot simulate the vacuum desorption process. Furthermore, the adsorption and desorption performances at high pressures are rarely discussed. In this study, the perovskite SrCo0.8Fe0.2O3−δ (SCF82) is prepared, and its isotherm and oxygen sorption and desorption kinetics are studied at 400 °C using both TGA and a high-pressure adsorption instrument. The high pressure adsorption and desorption performance confirms that VPSA is more suitable for oxygen production than pressure swing adsorption (PSA). The high-pressure adsorption instrument simulates the vacuum desorption process more effectively than TGA. A high vacuum desorption rate was found, indicating that the adsorption rate has a greater influence than the desorption rate when considering perovskite oxide adsorbents for use with VPSA techniques.
PubDate: 2017-11-29
DOI: 10.1007/s10450-017-9922-1

• Adsorption of short chain carboxylic acids from aqueous solution by
swellable organically modified silica materials
• Authors: Paul L. Edmiston; Alyssa R. Gilbert; Zachary Harvey; Noël Mellor
PubDate: 2017-11-29
DOI: 10.1007/s10450-017-9923-0

• Interaction of photosynthetic pigments with single-walled carbon nanotube
(15, 15): a molecular dynamics study
• Authors: Majid Ghasemi-Kooch; Maryam Dehestani
Abstract: In this study, adsorption of photosynthetic pigments on the inner and outer surfaces of single-walled carbon nanotube (15, 15) has been investigated using molecular dynamics simulation. The binding free energy is calculated by using the linear interaction energy algorithm, that its value indicates the adsorption of all pigments is desirable in both positions. Also, despite the high similarity between each category of these pigments, their interaction with the nanotube is different, that this result can be useful to separate these pigments from one another. According to Lennard–Jones potential energy between the pigments and carbon nanotube, the interaction on the inner surface is stronger than that on the outer surface for all pigments. The chlorophylls phytol tail interacts more strongly with the nanotube compared with the porphyrin ring of chlorophylls. The ability of carotenoids to institute π–π stacking is attributed to conjugated system. Furthermore, xanthophylls due to hydrogen bonded to oxygen atom form semi-hydrogen bonds with carbon nanotube.
PubDate: 2017-11-27
DOI: 10.1007/s10450-017-9920-3

• Adsorption of toxic SO x molecules on heterostructured TiO 2 /ZnO
nanocomposites for gas sensing applications: a DFT study
• Authors: Amirali Abbasi; Jaber Jahanbin Sardroodi
Abstract: Using density functional theory (DFT) calculations, we predict the SOx sensing performance of heterostructured TiO2/ZnO nanocomposites with and without nitrogen doping. The interaction of SO2 and SO3 molecules with the considered nanocomposites were examined based on different orientations of the gas molecules towards the nanocomposite. The fivefold coordinated titanium atoms were found to be the binding sites on the TiO2 side of nanocomposite, whereas, on the ZnO side, the oxygen atom acts as a binding site. Our theoretical results demonstrate that the interaction of SOx molecules with N-doped nanocomposites is more energetically favorable than that with undoped ones, indicating that N-doped TiO2/ZnO nanocomposites show stronger chemisorption and greater electron transfer effects than undoped TiO2/ZnO. The electronic properties of the adsorption systems were investigated in terms of the projected density of states and molecular orbitals. After the adsorption process, all S–O bonds of the SOx molecules were elongated, which is probably attributed the electron density transfer from the S–O bonds to the newly formed bonds between the nanocomposite and SOx molecules. The charge transfer analysis revealed that N-doped nanocomposite acts as a donor. The N-doped nanocomposite induce dramatic changes of electronic properties of TiO2/ZnO, which can be useful feature for improving the gas sensing performance. Our calculation results aim to provide some information for future experiment.
PubDate: 2017-11-27
DOI: 10.1007/s10450-017-9926-x

equilibrium and breakthrough of 1,2-dichloroethane
• Authors: Lijuan Jia; Qiuyi Shi; Siyuan Xie; Chao Long
PubDate: 2017-11-22
DOI: 10.1007/s10450-017-9919-9

• Development of averaged solid–fluid potential energies for layers and
solids of various geometries and dimensionality
• Authors: Lumeng Liu; Yonghong Zeng; D. D. Do; D. Nicholson; Junjie Liu
Abstract: The solid–fluid (SF) interaction energy describes the affinity between one adsorbate molecule and a solid. Its quantification is an essential input for the simulation of the adsorption isotherm, the isosteric heat and details of the microscopic structure of the adsorbate. A good approximation to the SF energy can be obtained by direct summation of all effective pairwise interaction energies (LJ plus electrostatic) between an adsorbate molecule and all the atoms in the solid. To repeat this summation for each new configuration in a simulation is very time-consuming. One resolution is to construct database tables of the solid–fluid potentials, which leads to massive databases if the grid separation used is very small. For solids that have simple geometries an alternative is to determine the approximate solid–fluid potential by ignoring the discrete atomic structure of the solid. This level of approximation is adequate for many simulations of engineering interest where fine details, for example in the first adsorbate layer, are not necessary. In this paper, we report comprehensive derivations of solid–fluid potentials for a wide range of solids, in layered structures with constant surface atom density or solid structures with constant atom density, and various curvatures and dimensions. These solids are common in engineering applications and the derived analytical solutions will be of value to scientists and engineers. We take a finite solid as an example of the application of the SF potential equations developed in this paper, and show the spatial variation of the solid–fluid potential energy in the neighbourhood of the edges of the solid, which is found to be remarkably different from the usual 1D potential energy equation commonly used in the adsorption literature.
PubDate: 2017-11-20
DOI: 10.1007/s10450-017-9921-2

• Bio-butanol downstream processing: regeneration of adsorbents and
selective exclusion of fermentation by-products
• Authors: R. Goerlitz; L. Weisleder; S. Wuttig; S. Trippel; K. Karstens; P. Goetz; H. Niebelschuetz
Abstract: Due to the decreasing availability of fossil resources and the negative effects on the global climate, an alternative to the petrochemical industry for the production of chemicals and fuels has to be developed. Bio-butanol is one of the most promising substitutes for gasoline and platform chemicals. However, the economical production of butanol by fermentation is limited by several factors. Since butanol is toxic for the cells, only low concentrations can be achieved in the fermentation broth. A recovery of butanol by distillation consumes more energy than the purified product contains and therefore is uneconomic. As an alternative, the purification of butanol by adsorption is a promising energy efficient technique. In this work adsorption isotherms for the resin SP-207 and the activated carbons AC 207C and CAL TR were determined for butanol solutions and synthetic fermentation broths at pH 4 and 5. The specific loading for butanol in the synthetic fermentation broth with pH 4 was decreased up to 53% at a butanol concentration of 4 g L− 1 compared to the pure butanol–water solution. The reduction was mainly caused by a replacement of butanol by butyric and acetic acid. To prevent the replacement, a selective pre-separation of the acids by the anion exchange resin MP 62 WS was tested. The resin showed affinity for the acids only, no solvent adsorption was observed. A pH shift of the medium from 4 to 5 led to a strong increase of the butanol adsorption. Furthermore, a screening test for the thermal regeneration of the three adsorption materials showed a drop of the butanol loading after the first cycle for the activated carbons, but not for the resin and allowed a pre-selection for further desorption tests.
PubDate: 2017-11-15
DOI: 10.1007/s10450-017-9918-x

JournalTOCs
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
Email: journaltocs@hw.ac.uk
Tel: +00 44 (0)131 4513762
Fax: +00 44 (0)131 4513327

Home (Search)
Subjects A-Z
Publishers A-Z
Customise
APIs