Subjects -> ENGINEERING (Total: 2918 journals)
    - CHEMICAL ENGINEERING (259 journals)
    - CIVIL ENGINEERING (255 journals)
    - ELECTRICAL ENGINEERING (182 journals)
    - ENGINEERING (1464 journals)
    - ENGINEERING MECHANICS AND MATERIALS (476 journals)
    - HYDRAULIC ENGINEERING (60 journals)
    - INDUSTRIAL ENGINEERING (101 journals)
    - MECHANICAL ENGINEERING (121 journals)

ENGINEERING (1464 journals)                  1 2 3 4 5 6 7 8 | Last

Showing 1 - 200 of 1205 Journals sorted alphabetically
3 Biotech     Open Access   (Followers: 9)
3D Research     Hybrid Journal   (Followers: 22)
AAPG Bulletin     Hybrid Journal   (Followers: 11)
Abstract and Applied Analysis     Open Access   (Followers: 4)
Aceh International Journal of Science and Technology     Open Access   (Followers: 9)
ACS Nano     Hybrid Journal   (Followers: 448)
Acta Geotechnica     Hybrid Journal   (Followers: 7)
Acta Metallurgica Sinica (English Letters)     Hybrid Journal   (Followers: 10)
Acta Nova     Open Access   (Followers: 1)
Acta Polytechnica : Journal of Advanced Engineering     Open Access   (Followers: 4)
Acta Scientiarum. Technology     Open Access   (Followers: 3)
Acta Universitatis Cibiniensis. Technical Series     Open Access   (Followers: 1)
Active and Passive Electronic Components     Open Access   (Followers: 8)
Adaptive Behavior     Hybrid Journal   (Followers: 9)
Adsorption     Hybrid Journal   (Followers: 5)
Advanced Energy and Sustainability Research     Open Access   (Followers: 7)
Advanced Engineering Forum     Full-text available via subscription   (Followers: 14)
Advanced Engineering Research     Open Access  
Advanced Journal of Graduate Research     Open Access   (Followers: 4)
Advanced Quantum Technologies     Hybrid Journal   (Followers: 1)
Advanced Science     Open Access   (Followers: 13)
Advanced Science Focus     Free   (Followers: 7)
Advanced Science Letters     Full-text available via subscription   (Followers: 13)
Advanced Science, Engineering and Medicine     Partially Free   (Followers: 11)
Advanced Synthesis & Catalysis     Hybrid Journal   (Followers: 20)
Advanced Theory and Simulations     Hybrid Journal   (Followers: 5)
Advances in Catalysis     Full-text available via subscription   (Followers: 8)
Advances in Complex Systems     Hybrid Journal   (Followers: 12)
Advances in Engineering Software     Hybrid Journal   (Followers: 31)
Advances in Fuel Cells     Full-text available via subscription   (Followers: 20)
Advances in Fuzzy Systems     Open Access   (Followers: 5)
Advances in Geosciences (ADGEO)     Open Access   (Followers: 22)
Advances in Heat Transfer     Full-text available via subscription   (Followers: 30)
Advances in Human Factors/Ergonomics     Full-text available via subscription   (Followers: 27)
Advances in Magnetic and Optical Resonance     Full-text available via subscription   (Followers: 10)
Advances in Natural Sciences : Nanoscience and Nanotechnology     Open Access   (Followers: 36)
Advances in Operations Research     Open Access   (Followers: 14)
Advances in OptoElectronics     Open Access   (Followers: 6)
Advances in Physics Theories and Applications     Open Access   (Followers: 21)
Advances in Polymer Science     Hybrid Journal   (Followers: 53)
Advances in Porous Media     Full-text available via subscription   (Followers: 6)
Advances in Remote Sensing     Open Access   (Followers: 58)
Advances in Science and Research (ASR)     Open Access   (Followers: 8)
Aerobiologia     Hybrid Journal   (Followers: 4)
Aerospace Systems     Hybrid Journal   (Followers: 10)
African Journal of Science, Technology, Innovation and Development     Hybrid Journal   (Followers: 8)
AIChE Journal     Hybrid Journal   (Followers: 38)
Ain Shams Engineering Journal     Open Access   (Followers: 7)
Al-Nahrain Journal for Engineering Sciences     Open Access  
Al-Qadisiya Journal for Engineering Sciences     Open Access   (Followers: 2)
AL-Rafdain Engineering Journal     Open Access   (Followers: 3)
Alexandria Engineering Journal     Open Access   (Followers: 3)
AMB Express     Open Access   (Followers: 1)
American Journal of Applied Sciences     Open Access   (Followers: 27)
American Journal of Engineering and Applied Sciences     Open Access   (Followers: 12)
American Journal of Engineering Education     Open Access   (Followers: 20)
American Journal of Environmental Engineering     Open Access   (Followers: 16)
American Journal of Industrial and Business Management     Open Access   (Followers: 31)
Annals of Civil and Environmental Engineering     Open Access   (Followers: 3)
Annals of Combinatorics     Hybrid Journal   (Followers: 3)
Annals of Pure and Applied Logic     Open Access   (Followers: 6)
Annals of Regional Science     Hybrid Journal   (Followers: 10)
Annals of Science     Hybrid Journal   (Followers: 10)
Annual Journal of Technical University of Varna     Open Access   (Followers: 1)
Antarctic Science     Hybrid Journal   (Followers: 1)
Applicable Algebra in Engineering, Communication and Computing     Hybrid Journal   (Followers: 3)
Applicable Analysis: An International Journal     Hybrid Journal   (Followers: 2)
Applications in Energy and Combustion Science     Open Access   (Followers: 2)
Applications in Engineering Science     Open Access   (Followers: 1)
Applied Catalysis A: General     Hybrid Journal   (Followers: 8)
Applied Catalysis B: Environmental     Hybrid Journal   (Followers: 22)
Applied Clay Science     Hybrid Journal   (Followers: 6)
Applied Computational Intelligence and Soft Computing     Open Access   (Followers: 16)
Applied Engineering Letters     Open Access   (Followers: 3)
Applied Magnetic Resonance     Hybrid Journal   (Followers: 4)
Applied Nanoscience     Open Access   (Followers: 11)
Applied Network Science     Open Access   (Followers: 3)
Applied Numerical Mathematics     Hybrid Journal   (Followers: 6)
Applied Physics Research     Open Access   (Followers: 7)
Applied Sciences     Open Access   (Followers: 6)
Applied Spatial Analysis and Policy     Hybrid Journal   (Followers: 6)
Arab Journal of Basic and Applied Sciences     Open Access  
Arabian Journal for Science and Engineering     Hybrid Journal   (Followers: 5)
Archives of Computational Methods in Engineering     Hybrid Journal   (Followers: 6)
Archives of Thermodynamics     Open Access   (Followers: 13)
Arctic     Open Access   (Followers: 7)
Arid Zone Journal of Engineering, Technology and Environment     Open Access   (Followers: 2)
Arkiv för Matematik     Hybrid Journal   (Followers: 1)
ArtefaCToS : Revista de estudios sobre la ciencia y la tecnología     Open Access   (Followers: 1)
Asia-Pacific Journal of Science and Technology     Open Access  
Asian Engineering Review     Open Access  
Asian Journal of Applied Science and Engineering     Open Access   (Followers: 2)
Asian Journal of Applied Sciences     Open Access   (Followers: 2)
Asian Journal of Biotechnology     Open Access   (Followers: 9)
Asian Journal of Control     Hybrid Journal  
Asian Journal of Technology Innovation     Hybrid Journal   (Followers: 7)
Assembly Automation     Hybrid Journal   (Followers: 2)
ATZagenda     Hybrid Journal  
ATZextra worldwide     Hybrid Journal  
AURUM : Mühendislik Sistemleri ve Mimarlık Dergisi = Aurum Journal of Engineering Systems and Architecture     Open Access   (Followers: 1)
Australasian Journal of Engineering Education     Hybrid Journal   (Followers: 3)
Australasian Physical & Engineering Sciences in Medicine     Hybrid Journal   (Followers: 1)
Australian Journal of Multi-Disciplinary Engineering     Hybrid Journal   (Followers: 2)
Autocracy : Jurnal Otomasi, Kendali, dan Aplikasi Industri     Open Access  
Automotive and Engine Technology     Hybrid Journal  
Automotive Experiences     Open Access  
Automotive Innovation     Hybrid Journal   (Followers: 1)
Avances en Ciencias e Ingenierías     Open Access  
Avances: Investigación en Ingeniería     Open Access   (Followers: 6)
Balkan Region Conference on Engineering and Business Education     Open Access   (Followers: 2)
Bangladesh Journal of Scientific and Industrial Research     Open Access  
Basin Research     Hybrid Journal   (Followers: 6)
Batteries     Open Access   (Followers: 11)
Batteries & Supercaps     Hybrid Journal   (Followers: 7)
Bautechnik     Hybrid Journal   (Followers: 3)
Bell Labs Technical Journal     Hybrid Journal   (Followers: 29)
Beni-Suef University Journal of Basic and Applied Sciences     Open Access   (Followers: 3)
Beyond : Undergraduate Research Journal     Open Access  
Bhakti Persada : Jurnal Aplikasi IPTEKS     Open Access  
Bharatiya Vaigyanik evam Audyogik Anusandhan Patrika (BVAAP)     Open Access   (Followers: 1)
Bilge International Journal of Science and Technology Research     Open Access   (Followers: 1)
Biointerphases     Open Access   (Followers: 1)
Biomaterials Science     Full-text available via subscription   (Followers: 14)
Biomedical Engineering     Hybrid Journal   (Followers: 15)
Biomedical Engineering and Computational Biology     Open Access   (Followers: 13)
Biomedical Engineering Letters     Hybrid Journal   (Followers: 5)
Biomedical Engineering: Applications, Basis and Communications     Hybrid Journal   (Followers: 5)
Biomedical Microdevices     Hybrid Journal   (Followers: 8)
Biomedical Science and Engineering     Open Access   (Followers: 7)
Biomicrofluidics     Open Access   (Followers: 7)
Biotechnology Progress     Hybrid Journal   (Followers: 44)
Black Sea Journal of Engineering and Science     Open Access  
Botswana Journal of Technology     Full-text available via subscription   (Followers: 1)
Boundary Value Problems     Open Access   (Followers: 1)
Brazilian Journal of Science and Technology     Open Access   (Followers: 2)
Bulletin of Canadian Petroleum Geology     Full-text available via subscription   (Followers: 13)
Bulletin of Engineering Geology and the Environment     Hybrid Journal   (Followers: 15)
Bulletin of the Crimean Astrophysical Observatory     Hybrid Journal  
Cahiers Droit, Sciences & Technologies     Open Access   (Followers: 1)
Calphad     Hybrid Journal   (Followers: 2)
Canadian Geotechnical Journal     Hybrid Journal   (Followers: 30)
Canadian Journal of Remote Sensing     Full-text available via subscription   (Followers: 50)
Carbon Resources Conversion     Open Access   (Followers: 3)
Carpathian Journal of Electronic and Computer Engineering     Open Access  
Case Studies in Engineering Failure Analysis     Open Access   (Followers: 6)
Case Studies in Thermal Engineering     Open Access   (Followers: 8)
Catalysis Communications     Hybrid Journal   (Followers: 7)
Catalysis Letters     Hybrid Journal   (Followers: 3)
Catalysis Reviews: Science and Engineering     Hybrid Journal   (Followers: 9)
Catalysis Science and Technology     Hybrid Journal   (Followers: 13)
Catalysis Surveys from Asia     Hybrid Journal   (Followers: 4)
Catalysis Today     Hybrid Journal   (Followers: 8)
CEAS Space Journal     Hybrid Journal   (Followers: 6)
Cell Reports Physical Science     Open Access  
Cellular and Molecular Neurobiology     Hybrid Journal   (Followers: 2)
Central European Journal of Engineering     Hybrid Journal  
Chaos : An Interdisciplinary Journal of Nonlinear Science     Hybrid Journal   (Followers: 3)
Chaos, Solitons & Fractals     Hybrid Journal   (Followers: 3)
Chaos, Solitons & Fractals : X     Open Access   (Followers: 1)
Chinese Journal of Catalysis     Full-text available via subscription   (Followers: 3)
Chinese Journal of Engineering     Open Access   (Followers: 2)
Chinese Journal of Population, Resources and Environment     Open Access  
Chinese Science Bulletin     Open Access   (Followers: 1)
Ciencia e Ingenieria Neogranadina     Open Access  
Ciencia en su PC     Open Access   (Followers: 1)
Ciencia y Tecnología     Open Access  
Ciencias Holguin     Open Access   (Followers: 2)
CienciaUAT     Open Access   (Followers: 1)
Cientifica     Open Access  
CIRP Annals - Manufacturing Technology     Hybrid Journal   (Followers: 11)
CIRP Journal of Manufacturing Science and Technology     Hybrid Journal   (Followers: 14)
City, Culture and Society     Hybrid Journal   (Followers: 27)
Clay Minerals     Hybrid Journal   (Followers: 9)
Coal Science and Technology     Full-text available via subscription   (Followers: 4)
Coastal Engineering     Hybrid Journal   (Followers: 14)
Coastal Engineering Journal     Hybrid Journal   (Followers: 9)
Coastal Engineering Proceedings : Proceedings of the International Conference on Coastal Engineering     Open Access   (Followers: 2)
Coastal Management     Hybrid Journal   (Followers: 30)
Coatings     Open Access   (Followers: 4)
Cogent Engineering     Open Access   (Followers: 3)
Cognitive Computation     Hybrid Journal   (Followers: 3)
Color Research & Application     Hybrid Journal   (Followers: 4)
COMBINATORICA     Hybrid Journal  
Combustion Theory and Modelling     Hybrid Journal   (Followers: 17)
Combustion, Explosion, and Shock Waves     Hybrid Journal   (Followers: 20)
Communications Faculty of Sciences University of Ankara Series A2-A3 Physical Sciences and Engineering     Open Access  
Communications in Numerical Methods in Engineering     Hybrid Journal   (Followers: 2)
Components, Packaging and Manufacturing Technology, IEEE Transactions on     Hybrid Journal   (Followers: 28)
Composite Interfaces     Hybrid Journal   (Followers: 10)
Composite Structures     Hybrid Journal   (Followers: 334)
Composites Part A : Applied Science and Manufacturing     Hybrid Journal   (Followers: 276)
Composites Part B : Engineering     Hybrid Journal   (Followers: 311)
Composites Part C : Open Access     Open Access   (Followers: 3)
Composites Science and Technology     Hybrid Journal   (Followers: 245)
Comptes Rendus : Mécanique     Open Access   (Followers: 2)
Computation     Open Access   (Followers: 1)
Computational Geosciences     Hybrid Journal   (Followers: 20)
Computational Optimization and Applications     Hybrid Journal   (Followers: 11)
Computer Applications in Engineering Education     Hybrid Journal   (Followers: 6)
Computer Science and Engineering     Open Access   (Followers: 20)

        1 2 3 4 5 6 7 8 | Last

Similar Journals
Journal Cover
Adsorption
Journal Prestige (SJR): 0.703
Citation Impact (citeScore): 2
Number of Followers: 5  
 
  Hybrid Journal Hybrid journal (It can contain Open Access articles)
ISSN (Print) 1572-8757 - ISSN (Online) 0929-5607
Published by Springer-Verlag Homepage  [2658 journals]
  • Special issue on the 13th Brazilian meeting on adsorption

    • Free pre-print version: Loading...

      PubDate: 2021-10-08
       
  • Insights of adsorption isotherms with different gases at 77 K and their
           use to assess the BET area of nanoporous silica materials

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      Abstract: There is a well-known relationship between porous materials performance in a given process and their textural properties. These properties include specific surface area, among others, where the most widely used experimental technique to determine them is gas adsorption. Although the most used adsorptive gas is N2 at 77 K up to atmospheric pressure, its quadrupole moment generates specific interactions with surface groups, as silanols in silica materials, causing a preferential orientation effect on the adsorbed N2 molecule affecting the specific surface area value. In this sense, we analyzed the adsorption–desorption isotherms at 77 K of nanoporous silica materials using different adsorptives. From these data, we obtained the specific surface area (SBET) values of the samples by applying the BET method with the IUPAC recommendations for each gas. The selected materials were MCM-41, MCM-48, SBA-15, and SBA-16, and the adsorptives used were Ar, O2, and CH4, along with N2. Among the chosen adsorptives, Ar and CH4 do not have a quadrupole moment, whereas this value is present for N2 and O2, being the latter four times smaller than nitrogen. In addition, at 77 K, both Ar and CH4 are below their triple-point temperature, while N2 and O2, which are above their triple-point temperature, are in the same thermodynamic state. Taking the SBET obtained by Ar at 77 K as the referential value of each sample, the corresponding molecular transversal areas of the other adsorptives were estimated. It was found that the variation of transversal area for the N2 molecule at 77 K on silica materials was between 0.133 and 0.149 nm2 (below its common value of 0.162 nm2). In contrast, in the case of the O2 molecule at 77 K, this value was almost constant, with an average of 0.123 nm2. These results showed that the quadrupole moment of the O2 does not play an important role in the interaction with surface silanol groups present in the samples, making oxygen at 77 K a potential and reliable adsorptive to determine the specific surface area of silica materials.
      PubDate: 2021-09-20
       
  • The binding interaction of protein on a charged surface using
           Poisson–Boltzmann equation: lysozyme adsorption onto SBA-15

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      Abstract: A modified Poisson–Boltzmann model (PBEm) can be successfully used to determine the binding strength parameter, i.e., (Henry constant, K), for the protein adsorbent interaction in ion-exchanger columns. Lysozyme has been employed as a standard protein for the adsorption in a mesoporous silica adsorbent. The density of aminoacid groups and silanol groups were used as inputs to calculate the protein charge density as a function of pH, salt concentration, and type of salt. Using the electrostatic potential provided as solving the PBEm with the protein charge surface and silanol wall as boundaries conditions, we calculated the K through the potential of mean force to describe the whole set of experimental data. The unique estimated parameter in this work was the volumetric accessible surface area from isotherm data for different electrolyte conditions. The results show that the protocol applied includes a pH and ionic strength dependence in the Langmuir isotherm. A sensibility test with different anions ( \(\text {Cl}^{-}\) , \(\text {Br}^{-}\) , and \(\text {I}^{-}\) ) showed an agreement with the Hofmeister series for the protein/adsorbent interaction. A modification in the electrolyte concentration and pH can change the behavior of the isotherm profile for a fixed value of saturation capacity, independently calculated for spheres packed in cylinders. The calculations provide here can be helpful for the optimization of the best condition for protein adsorption.
      PubDate: 2021-09-17
       
  • Mesoporous metal–organic framework MIL-100(Fe) as drug carrier

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      Abstract: The use of hybrid nanomaterials for the controlled delivery of drugs in the body has attracted great scientific attention. Indeed, much effort has been put in the experimental or theoretical screening of drug loading in different biocompatible frameworks, however, full molecular-level investigations of drug adsorption in porous structures are still scarce. Herein we aim to understand the molecular mechanisms behind the good performance of the mesoporous metal–organic framework MIL-100(Fe) with respect to the adsorption of a wide range of therapeutical drugs. To this purpose, a microscopic model was developed and further validated by comparing theoretical and experimental water isotherms and the maximum uptake of two model drugs (ibuprofen and caffeine). We have found that MIL-100(Fe) has an excellent mass uptake for the 5-fluorouracil (5-FU) anti-tumoral drug molecule despite presenting a relatively weak drug/MOF interaction. We also perform detailed studies in the adsorption mechanism and sitting of the doxorubicin (DOX) molecule and how the presence of water in the structure affects the DOX-framework interactions. The good performance of the MOF MIL-100(Fe) is closely related to the diversity of interaction sites, both hydrophobic and hydrophilic. This is a desirable feature to maximize the potential of any candidate for drug carrier.
      PubDate: 2021-09-03
       
  • Adsorption kinetics and equilibria of two methanol samples with different
           water content on activated carbon

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      Abstract: To investigate the influence of fluid purity on the adsorption properties, adsorption kinetics and adsorption equilibria of two methanol samples with different water content on an activated carbon were studied. The purity of the methanol samples was 98.5% and 99.9%. Measurements were conducted at 298 K and 318 K using a magnetic suspension balance and cover a wide p/p0 range. To determine effective diffusion time constants and mass transfer coefficients, adsorption kinetics were evaluated using an isothermal and a nonisothermal Fickian diffusion model, and the linear driving force model. The pressure dependence of the kinetic parameters was studied and discussed. A small influence of sample purity on the adsorption equilibria was observed, as the purer methanol sample showed slightly higher equilibrium loadings than the less pure sample. However, significantly faster adsorption kinetics were observed for the purer sample at all temperature and pressure conditions. Compared to the less pure sample, the determined effective diffusion time constants and the mass transfer coefficients were up to 98% and 35% higher, respectively.
      PubDate: 2021-09-03
       
  • Characterization of mesoporous region by the scanning of the hysteresis
           loop in adsorption–desorption isotherms

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      Abstract: The scanning hysteresis loop provides information about the correlation of the pore network, its connectivity and pore size distribution; nonetheless, this correlation cannot be revealed from the complete isotherm. To analyze the connectivity of the porous network in ordered mesoporous materials modified with iron and cobalt oxides, Ar adsorption–desorption isotherms and their corresponding scanning of the hysteresis loops at three temperatures (65, 77, and 87 K) were measured. Two mathematical models based on the independent domains theory (i.e. Uncorrelated Model (UM) and Partial Correlated Model (PCM)) were applied to adjust the desorption branches in the hysteresis loops associating these results to the connectivity in the porous network and the presence of pore-blocking effects.
      PubDate: 2021-09-01
       
  • In-situ cost-effective synthesis of zeolite A in Al2O3–SiO2 glass fibers
           for fixed bed adsorption of Cu2+, Cd2+ and Pb2+

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      Abstract: The in-situ coating of zeolite crystals on Al2O3–SiO2 glass fiber was investigated using two commercial fibers (FB1 and FB2). The fibers were submitted to hydrothermal treatment at different temperatures, resulting in the crystallization of zeolite on their surfaces. The materials obtained were characterized by X-ray fluorescence, X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy. Batch and fixed bed essays were carried out to evaluate the performance of the materials in the adsorption Cu2+, Cd2+ and Pb2+ from aqueous solutions, at 28 ± 2 °C. The syntheses in which the FB1 sample was employed resulted in zeolite A as the only crystalline phase. The exception was the FB1-100 material which sodalite was also formed. When FB2 samples were used, only the FB2-85 material indicated resulted in zeolite A without secondary phases, while the other materials presented a mixture of phases. The materials FB1-95 and FB2-95 presented better performance in batch adsorption experiments than the other samples, with Qe for FB1-95 being 0.049 mmol g−1 for the three metal ions, and Qe for FB2-95 being 0.043, 0.047, and 0.049 mmoL g−1 for Cu2+, Cd2+ and Pb2+, respectively. Therefore, these samples were selected for the study of fixed bed adsorption. The following adsorption order was verified: Pb2+  > Cd2+  > Cu2+. Linear Driving Force (LDF) model proved to be suitable for the adsorption experimental data, confirming the high potential of the FB1-95 and FB2-95 materials for the adsorption of Cu2+, Cd2+ and Pb2+ in aqueous solution.
      PubDate: 2021-08-25
       
  • Multiscale design of a pressure swing adsorption process for natural gas
           purification

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      Abstract: Adsorption processes with activated carbons can be used to remove heavy hydrocarbons from a natural gas flow. Using the Pressure Swing Adsorption (PSA) technology, one can introduce a flexible solution in pre-existing gas-processing units to deal with new marked demands, as for example a C3+ free gas composition to be used as adsorbed natural gas to vehicles fuel tanks. However, designing a PSA process is a laborious task because several cycle configurations and materials are available to perform the separation. To fulfill such task, a multiscale procedure is proposed. Molecular simulation, through Grand Canonical Monte Carlo (GCMC) method, was used to obtain adsorption isotherms for natural gas components in three different carbons: WV-1050, NORIT R1 and MAXSORB. Bed geometry was set based on the minimum fluidization velocity and on the working capacity of the adsorbents. Working capacities were calculated using Langmuir Isotherm applied to Ideal Adsorbed Solution Theory (IAST) to represent the mixture. Each PSA column was simulated in Aspen Adsorption® and operates according to a four steps cycle (Skarstrom cycle): pressurization, adsorption at 40 bar, blowdown, and purge at 1 bar. The operating conditions of the process (such as flowrates, bed geometry and step times) were optimized, seeking the maximization of the process performance parameters: purity, recovery and productivity. A preliminary design of the PSA unit indicates the carbon WV1050 as the best adsorbent to produce C3+ free gas fuel, ideal for storage by adsorption.
      PubDate: 2021-08-25
       
  • Saturation loadings on 5A zeolite above and below the critical conditions:
           monatomic species data evaluation and modeling

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      Abstract: Isotherms for monatomic species (He, Ne, Ar, Kr and Xe) adsorption on 5A zeolite are extracted from the literature and analyzed for consistency and saturation. The saturation data below the critical adsorbate reduced temperature, TCAR, is modeled using the Rackett equation and the zeolite structure. Consideration is made regarding whether adsorbates can enter β cage in addition to the α cage. The data for argon and krypton suggest that both species may also enter the β cage, although there is not enough information to be conclusive. Xenon does not enter the β cage. The limited data establishes the need for further study on this point. The subTCAR data for both 5A and 13X are relatively consistent with the proposed subTCAR model. Although there is not sufficient data to determine this for helium or neon, their size and the literature suggest that both molecules enter the β cage. The data are divided into subTCAR and superTCAR regions, where TCAR is the critical reduced temperature for the adsorbed species, which often differs from 1. The subTCAR model predictions for argon and krypton are excellent, while that for xenon requires a steric factor of 0.76. For superTCAR data, helium has only one data point. The superTCAR data for argon, krypton and xenon are linear with excellent regression coefficients. Intersection of the linear superTCAR plots with the subTCAR model prediction curves gave TCAR’s of 0.996 for argon, 0.80 for krypton and 0.66 to 0.86 for xenon. Literature models Ruthven et al. (Chem Eng Sci 28:701–709, 1973), Ozawa et al. (J Colloid Interface Sci 56(1):83–91, 1976), and Dubinin (in: Caldenhead (ed) Prog. surface and membrane science, Academic Press, New York, 1975) expressed in terms of qmax are also fitted to the data with some success. A modified Ozawa et al. model fits the data reasonably well. Data for 4A, 5A and 13X are observed to be very similar.
      PubDate: 2021-08-24
       
  • CO2 capture by ethanolamines functionalized resins: amination and kinetics
           of adsorption in a fixed bed

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      Abstract: The main aim of this manuscript was to investigate the effect of amine (MEA, DEA and TEA) functionalization of high surface area supports (Amberlite IR120H, Ambersep 252H, Amberlite 200CNa and Amberlite XAD7HP) on adsorption of CO2 from gases streams. A saturated factorial design of experiments was initially applied to determine the influence of four amine impregnation variables on amine loading. Except for the amine concentration whose effect was significantly positive on the amount of ethanolamine impregnated in Amberlite XAD7HP (p ≤ 0.05), the other factors had negligible importance. Kinetic experiments of CO2 adsorption were performed in a fixed bed at different inlet concentrations of CO2 and temperatures. The amounts of adsorbed CO2 on the DEA enriched Ambersep 252H, Amberlite 200CNa and Amberlite XAD7HP at bed saturation were ~ 40–400 times as high as those obtained with the same adsorbents without impregnation. DEA enriched Amberlite IR120H and TEA functionalized resins presented small capacities to adsorb CO2 at the investigated conditions, while MEA enriched resins were effective as CO2 adsorbents in the case of impregnation in Amberlite 200CNa. A classical fundamental model described correctly the breakthrough curves for CO2 adsorption–desorption at concentrations of CO2 in the gas feed stream of 1%, 3% and 5% at 40 °C and 60 °C.
      PubDate: 2021-08-21
       
  • Impact of heteroatom addition into mesoporous silica for water adsorption
           in the low partial pressure range

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      Abstract: Mesoporous silicas are known to be high-performing water adsorbents in high humidity levels due to their large pore volumes. However, for low humidity conditions, these materials typically present a less expressive performance, which is a drawback for many applications. In the present report, mesoporous silica SBA-15 was functionalized with Al, Ti, Zr and Li in order to improve their performance in this condition. The influence of functionalization in porosity, morphology and acidic sites was investigated. Samples with an increased number of acidic sites and with higher microporosity when compared to pure silica were produced. This was responsible for their enhanced performance for water adsorption in low moisture conditions. Sample functionalized with zirconium in SBA-15 synthesis improved the water adsorption capacity of pure silica by three times, reaching up to 127 g kg−1 at a relative pressure of 0.2 and 570 g kg−1 close to saturation pressure. This sample was found to be a promising material to be applied in processes which require high adsorption capacities in both low and high water partial pressure ranges. Moreover, the understanding of the mechanisms behind the heteroatom functionalization can be applied to any silica material in order to enhance its attractiveness towards any polar molecule.
      PubDate: 2021-08-17
       
  • Thermodynamics of methane adsorption on carbon adsorbent prepared from
           mineral coal

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      Abstract: Methane adsorption on a recuperated activated carbon, AR-V, was studied over the temperature range of 213–393 K and at pressures up to 10 MPa from the perspective of its potential application for adsorption-based storage and separation technologies. The porous structure, phase and chemical compositions of AR-V were examined by nitrogen adsorption at 77 K, x-ray diffraction, and scanning electron microscopy. The amount of adsorbed methane increased with pressure up to 6.3 mmol/g at 243 K and fell dramatically to ~ 1 mmol/g with a temperature rise to 393 K. The molar differential isosteric heat of methane adsorption on AR-V was evaluated from the linear isosteres within the studied P,T-range; the effects from the non-ideality of a gaseous phase and the AR-V non-inertness were considered. The maximal summarized contribution from the AR-V thermal expansion and directly measured adsorption-induced deformation to the molar differential isosteric heat of methane adsorption turned out to be less than that from the gas compressibility. The initial drastic changes in the thermodynamic state functions of the adsorption system were attributed to the binding methane molecules with non-uniformly distributed high-energy adsorption sites. When methane molecules occupied all high-energy adsorption sites, the subsequent variations in the thermodynamic functions were governed by the intensifying attractive forces between methane molecules upon methane adsorption resulting in the formation of adsorption clusters. The temperature dependence of the isosteric heat capacity of the methane/AR-V system varied during adsorption; its value exceeded 2–3 times the isochoric heat capacity of the equilibrium methane gaseous phase.
      PubDate: 2021-08-17
       
  • Water adsorption in fresh and thermally aged zeolites: equilibrium and
           kinetics

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      Abstract: Zeolites are widely employed in the industrial drying of gases by Temperature Swing Adsorption (TSA). In a typical TSA process, the adsorbent is packed in a fixed bed, which is sequentially subjected to a “cold” feed (adsorption) and a hot flush (desorption). Due to the hydrothermal stress, adsorbents may suffer from reduced drying capacity in long-term service. The aim of this work is to assess the impact of thermal aging of two zeolite materials (LTA and CHA) having similar pore openings but different Si/Al ratios. We examined how simulated thermal aging affected porous texture, coke deposition and water vapor adsorption equilibrium and kinetics. Both zeolites showed reduced uptake of probe molecules (N2 at 77 K and CO2 at 273 K) and water vapor (303 K) when subjected to simulated thermal aging. In Fourier-Transform Infrared Spectroscopy (FTIR) analyses, only the aged LTA zeolite showed bands related to the presence of aromatic compounds. Water vapor adsorption uptake decreased 28.6% and 18.4% for LTA and CHA at 30 mbar, respectively. Kinetic studies indicate a reduction in water diffusion coefficient after the aging cycles. Although LTA has a significantly higher affinity for water as compared to CHA, the latter is much more resistant to hydrothermal aging with comparatively faster water diffusion.
      PubDate: 2021-08-11
       
  • Performance of adsorption isotherms kernels of CO2 models for
           γ-alumina characterization

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      Abstract: γ-alumina is the most studied metastable phase of the alumina. It is recognized as a strategic material in many industrial processes, acting as adsorbent, catalyst or support due to its high surface area, thermal and chemical stability. Its heterogeneous surface imposes a challenge for characterization by adsorption. The use of experimental adsorption data, combined with the theoretical approach of molecular simulation is becoming the standard adsorption-based technique to characterization. Therefore, this study aims to launch a first insight in the performance of the atom–atom (AA) and united-atom (UA) molecular models of the CO2, a probe gas less prone to diffusion limitations, given the lack of an appropriate kernel for the γ-alumina characterization. A detailed experimental isotherm of CO2 in γ-alumina was performed and a collection of isotherms was calculated applying Monte Carlo method in the grand canonical ensemble. To build the kernel, isotherm in 10 different slit-pore sizes were calculated. The different pore filing regimes result in a kernel with good reliability window. With these CO2 kernels (AA and AU models), reasonable pore size distributions were predicted, capturing the low range of microporosity. Additional assessment with others probes gas is recommended to confirm the feasibility of CO2 as a characterizing molecule.
      PubDate: 2021-08-11
       
  • Influence of functionalization method on isomorphic substitution and
           formation of extra-framework oxides in silica for water vapor adsorption

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      Abstract: Water vapor adsorption is a process of great importance for several industries. Because of that, new materials formed by mesoporous silica with metallic heteroatom functionalization have been studied for water adsorption. This functionalization process is still little studied in the literature, with many topics remaining to be evaluated. One of them is how each functionalization method (grafting and co-condensation) influences the generation of isomorphic substitution or extra-framework oxides. Another is which of these configurations is most interesting for water adsorption. This work aims to address both questions. For this, two groups of samples were synthesized using grafting and co-condensation for the insertion of Al, Ti, Zr and Li into mesoporous silica SBA-15. These samples were analyzed using nitrogen adsorption, high resolution scanning microscopy, energy dispersive X-ray spectroscopy, magic angle spinning nuclear magnetic resonance, Fourier transform infrared spectroscopy, pyridine adsorption and water adsorption. These techniques revealed that the co-condensation approach used in this work was most interesting for water adsorption at low partial pressures. This occurred because it generated a higher degree of isomorphic substitution, which was found to be the most active configuration of heteroatoms for this application.
      PubDate: 2021-08-09
       
  • Letter to the editor

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      PubDate: 2021-08-07
       
  • Martin Bülow: response

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      PubDate: 2021-08-01
       
  • Correction to: The effect of atomic point charges on adsorption isotherms
           of CO2 and water in metal organic frameworks

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      Abstract: Recently, we presented a detailed and systematic molecular simulation study of the effect of point charges on adsorption of carbon dioxide and water in a series of typical MOF materials [1]. Unfortunately, we have since detected a mistake in one of the input files pertaining to water adsorption isotherm simulations—concretely, the structure of the water molecule was modelled as linear instead of obeying the correct H-O-H angle of 109.47º for the SPC/E model [2]. As we later found out, this led to a significant underestimation of the amount adsorbed in all water isotherms reported in our original paper, although the relative differences between isotherms obtained using different charge sets are qualitatively the same. We have repeated all the water adsorption simulations, and report the new results here in graphical format. With the exception of a few minor statements, which we also correct below, the conclusions of the original work remain unchanged.
      PubDate: 2021-08-01
       
  • Letter to the editor

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      PubDate: 2021-08-01
       
  • Prediction of affinity coefficient for estimation of VOC adsorption on
           activated carbon using V-matrix regression method

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      Abstract: Volatile organic compounds (VOCs) pose an ever-growing threat on human health and environment. Predicting VOC affinity coefficient and consequently estimating activated carbon adsorption requires fundamental understanding of adsorbate-adsorbent interaction, shape and hydrophilicity effects. Hence, a model which expressed these three factors with molecular descriptors was investigated with Ridge and V-matrix regression methods in two cases, k-fold cross-validation and random sampling technique. The results showed, the sole interaction term and the complete model decreased the root mean square error (RMSE) of polarizability ratio by approximately 19% and 26% respectively. The V-matrix regression, reduced the average Ridge RMSE by 9 and 19% for the first and second case. Lower than 10% errors were displayed by 104 out of 155 data and only 4 data which were small molecules with very high polarity had more than 30% error. For both cases the proposed model with V-matrix regression had better or similar results compared to previous research. However, the effect of reference compounds on highly polar VOCs requires further investigation. From the VOC adsorption estimation, it was evident that affinity and adsorption errors were in the same magnitude. Hence, with accurate prediction of affinity coefficient, adsorption isotherms of any VOC can be calculated.
      PubDate: 2021-08-01
       
 
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