Change search
Refine search result
1 - 27 of 27
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
Rows per page
  • 5
  • 10
  • 20
  • 50
  • 100
  • 250
Sort
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
  • Standard (Relevance)
  • Author A-Ö
  • Author Ö-A
  • Title A-Ö
  • Title Ö-A
  • Publication type A-Ö
  • Publication type Ö-A
  • Issued (Oldest first)
  • Issued (Newest first)
  • Created (Oldest first)
  • Created (Newest first)
  • Last updated (Oldest first)
  • Last updated (Newest first)
  • Disputation date (earliest first)
  • Disputation date (latest first)
Select
The maximal number of hits you can export is 250. When you want to export more records please use the Create feeds function.
  • 1.
    Cardenas, Edgar
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Aguilar, Wilson
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Zhou, Ming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering. Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering. Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Mouzon, Johanne
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Influence of the internal structure of the gel on Al-zoning in NBA-ZSM-5 crystalsIn: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093Article in journal (Other academic)
    Abstract [en]

    The crystallization of ZSM-5 from a gel comprising n-butylamine as structure directing agent was investigated. The samples were characterized by X-ray diffraction, nitrogen gas adsorption, extreme high-resolution transmission and scanning electron microscopy, and energy dispersive spectroscopy. The gel was found to be composed by a silica-rich matrix embedded in a skeleton of alumina-rich nanoparticles. During growth of the crystals, the silica-rich matrix is consumed first, and an increasing fraction of the alumina-rich nanoparticles are utilized later in the growth process. This leads to a non-uniform consumption of the gel walls during crystal growth. Consequently, the Si/Al ratio of the gel is steadily decreasing, which is accompanied by a corresponding decrease in the Si/Al ratio from the center to the outer surface of the crystals, i.e. Al-zoning of the ZSM-5 crystals.

  • 2.
    Du, Cuihua
    et al.
    State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China.
    Zhang, Xi
    State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China.
    Wang, Xiaodong
    State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China.
    Huang, Wei
    State Key Laboratory of Clean and Efficient Coal Utilization, Taiyuan University of Technology, Taiyuan 030024, Shanxi, China.
    Zhou, Ming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Preparation of PDA@PEBA2533 membranes for C3H6/N2 separation2024In: Huagong Jinzhan/Chemical Industry and Engineering Progress, ISSN 1000-6613, Vol. 43, no 1, p. 437-446Article in journal (Refereed)
  • 3.
    Faisal, Abrar
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Zhou, Ming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Recovery of butanol from model ABE fermentation broths using MFI adsorbent: a comparison between traditional beads and a structured adsorbent in the form of a film2016In: Adsorption, ISSN 0929-5607, E-ISSN 1572-8757, Vol. 22, no 2, p. 205-214Article in journal (Refereed)
    Abstract [en]

    Butanol, a promising biofuel, can be produced by ABE (acetone, butanol and ethanol) fermentation using e.g. Clostridium acetobutylicum. However, the butanol concentration in the resulting broth is limited to only ca. 20 g/L due to the toxicity for the microorganisms. This low product concentration demands an efficient recovery process for successful commercialization of this process. In this study, a structured adsorbent in the form of steel monolith coated with a silicalite-1 film was prepared using the in situ growth method. The adsorbent was carefully characterized by SEM and XRD. The performance of the adsorbent was evaluated by performing breakthrough experiments at room temperature using model ABE fermentation broths and the performance was compared with that of traditional adsorbents in the form of beads. The structured silicalite-1 adsorbent showed less saturation loading time as compared to commercial binder free silicalite-1 beads, reflecting the different dimensions of the columns used, set by experimental constraints. Studies of the desorption process showed that by operating at appropriate conditions, butanol with high concentration i.e. up to 95.2 wt% for butanol–water model system and 88.5 wt% for ABE fermentation broth can be obtained using the structured silicalite-1 adsorbent. Commercial silicalite-1 beads also showed good selectivity but the concentration of butanol in the desorbed product was limited to 70 % for the butanol–water model system and 69 % for ABE fermentation broth, probably as a result of entrained liquid between the beads.

  • 4.
    Faisal, Abrar
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Department of Chemical Engineering COMSATS Institute of Information Technology Lahore.
    Zhou, Ming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Zeolite MFI adsorbent for recovery of butanol from ABE fermentation broths produced from an inexpensive black liquor-derived hydrolyzate2018In: Biomass Conversion and Biorefinery, ISSN 2190-6815, E-ISSN 2190-6823, Vol. 8, no 3, p. 679-687Article in journal (Refereed)
    Abstract [en]

    In this work, high-silica MFI zeolite adsorbent was evaluated for selective recovery of butanol from a real ABE (acetone, butanol, and ethanol) fermentation broth by batch adsorption measurements. The fermentation broth was produced using a hydrolyzate originating from Kraft black liquor, an internal stream in pulp mills, i.e., a low-cost substrate. The adsorbent was very selective towards butanol and butyric acid and became nearly saturated with a mixture of butanol and butyric acid with relative amounts of butanol and butyric acid depending on the pH. The presence of phenolic compounds in significant amounts in the fermentation broths, originating from the black liquor hydrolyzate, did not affect the adsorption of butanol and butyric acid.

  • 5.
    Farzaneh, Amirfarrokh
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Zhou, Ming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Antzutkin, Oleg
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Bacsik, Zoltan
    Department of Materials and Environmental Chemistry, Stockholm University.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Adsorption of Butanol and Water Vapors in Silicalite‑1 Films with a Low Defect Density2016In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 32, p. 11789-11798Article in journal (Refereed)
    Abstract [en]

    Pure silica zeolites are potentially hydrophobic and have therefore been considered to be interesting candidates for separating alcohols, e.g., 1-butanol, from water. Zeolites are traditionally synthesized at high pH, leading to the formation of intracrystalline defects in the form of silanol defects in the framework. These silanol groups introduce polar adsorption sites into the framework, potentially reducing the adsorption selectivity toward alcohols in alcohol/water mixtures. In contrast, zeolites prepared at neutral pH using the fluoride route contain significantly fewer defects. Such crystals should show a much higher butanol/water selectivity than crystals prepared in traditional hydroxide (OH−) media. Moreover, silanol groups are present at the external surface of the zeolite crystals; therefore, minimizing the external surface of the studied adsorbent is important. In this work, we determine adsorption isotherms of 1-butanol and water in silicalite-1 films prepared in a fluoride (F−) medium using in situ attenuated total reflectance−Fourier transform infrared (ATR−FTIR) spectroscopy. This film was composed of well intergrown, plate-shaped b-oriented crystals, resulting in a low external area. Single-component adsorption isotherms of 1-butanol and water were determined in the temperature range of 35− 80 °C. The 1-butanol isotherms were typical for an adsorbate showing a high affinity for a microporous material and a large increase in the amount adsorbed at low partial pressures of 1-butanol. The Langmuir−Freundlich model was successfully fitted to the 1-butanol isotherms, and the heat of adsorption was determined. Water showed a very low affinity for the adsorbent, and the amounts adsorbed were very similar to previous reports for large silicalite-1 crystals prepared in a fluoride medium. The sample also adsorbed much less water than did a reference silicalite-1(OH−) film containing a high density of internal defects.The results show that silicalite-1 films prepared in a F− medium with a low density of defects and external area are very promising for the selective recovery of 1-butanol from aqueous solutions.

  • 6.
    Farzaneh, Amirfarrokh
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Zhou, Ming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Potapova, Elisaveta
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Bacsik, Zoltan
    Department of Material and Environmental Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden.
    Ohlin, Lindsay
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Adsorption of Water and Butanol in Silicalite-1 Film Studied with in-situ ATR-FTIR Spectroscopy2015In: Langmuir, ISSN 0743-7463, E-ISSN 1520-5827, Vol. 31, no 17, p. 4887-4894Article in journal (Refereed)
    Abstract [en]

    Biobutanol produced by, e.g., acetone–butanol–ethanol (ABE) fermentation is a promising alternative to petroleum-based chemicals as, e.g., solvent and fuel. Recovery of butanol from dilute fermentation broths by hydrophobic membranes and adsorbents has been identified as a promising route. In this work, the adsorption of water and butanol vapor in a silicalite-1 film was studied using in situ attenuated total reflectance–Fourier transform infrared (ATR–FTIR) spectroscopy to better understand the adsorption properties of silicalite-1 membranes and adsorbents. Single-component adsorption isotherms were determined in the temperature range of 35–120 °C, and the Langmuir model was successfully fitted to the experimental data. The adsorption of butanol is very favorable compared to that of water. When the silicalite-1 film was exposed to a butanol/water vapor mixture with 15 mol % butanol (which is the vapor composition of an aqueous solution containing 2 wt % butanol, a typical concentration in an ABE fermentation broth, i.e., the composition of the gas obtained from gas stripping of an ABE broth) at 35 °C, the adsorption selectivity toward butanol was as high as 107. These results confirm that silicalite-1 quite selectively adsorbs hydrocarbons from vapor mixtures. To the best of our knowledge, this is the first comprehensive study on the adsorption of water and butanol in silicalite-1 from vapor phase.

  • 7.
    Grahn, Mattias
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Faisal, Abrar
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Department of Chemical Engineering, COMSATS University Islamabad, Lahore Campus, Lahore, Pakistan.
    Öhrman, Olov G.W
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. RISE ETC - Energy Technology Center, SE-941 28 Piteå, Sweden.
    Zhou, Ming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Signorile, Matteo
    Department of Chemistry, NIS and INSTM Reference Centre, Università di Torino, Torino, Italy.
    Crocellà, Valentina
    Department of Chemistry, NIS and INSTM Reference Centre, Università di Torino, Torino, Italy.
    Nabavi, Mohammad Sadegh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Small ZSM-5 crystals with low defect density as an effective catalyst for conversion of methanol to hydrocarbons2020In: Catalysis Today, ISSN 0920-5861, E-ISSN 1873-4308, Vol. 345, p. 136-146Article in journal (Refereed)
    Abstract [en]

    This work presents the synthesis of nearly defect-free ZSM-5 nanosized crystals, prepared in fluoride medium by seeding with silicalite-1. This material was carefully characterized and its catalytic performances in the methanol to hydrocarbons (MTH) reaction were assessed. Such fluoride-based material was compared to a reference ZSM-5, produced through a conventional alkaline synthesis but from the same seeding. Despite both the materials show closely identical morphology and they have a comparable acid site population, the catalyst prepared using the fluoride route showed significantly longer lifetime in MTH compared to the catalyst prepared using conventional synthesis at high pH. The slower deactivation for the samples prepared using the fluoride route was ascribed, thanks to a thorough in situ IR spectroscopy study, to its lower density of internal defects. According to the UV-Raman characterization of coke on the spent catalyst, the fluoride-based ZSM-5 catalyst produces less molecular coke species, most probably because of the absence of enlarged cavities/channels as due to the presence of internal defects. On the basis of these observations, the deactivation mechanism in the ZSM-5 synthesized by fluoride medium could be mostly related to the deposition of an external layer of bulk coke, whereas in the alkali-synthesized catalyst an additional effect from molecular coke accumulating within the porous network accelerates the deactivation process.

  • 8.
    Hedlund, Jonas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Garcia, Gustavo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Balsamo, Marco
    Dipartimento di Scienze Chimiche, Università degli Studi di Napoli Federico II, Complesso Universitario di Monte Sant’ Angelo, 80126 Napoli, Italy.
    Zhou, Ming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Mouzon, Johanne
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Microchannel Zeolite 13X Adsorbent with High CO2 Separation Performance2021In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 277, article id 119483Article in journal (Refereed)
    Abstract [en]

    Uniform 13X films with thicknesses of 3 and 11 µm were grown on supports in the form of steel monoliths with a cell density of 1600 cpsi and microchannels width of 0.5 mm. Sharp breakthrough fronts and a dynamic uptake of 3.4 mmol CO2 g-1 zeolite were observed in the forwarding step of breakthrough experiments for a feed of 10 % CO2 in N2 with a high flow rate at 293 K and 1 bar. Numerical modeling showed that the adsorption process was very fast and that the transport of CO2 in the thin zeolite layer was the rate-limiting step, the mass transfer resistance for the 11 µm film is 2.2 times lower than zeolite 13X pellets and 100 times lower than zeolite 4A beads. Axial dispersion, pressure drop, and gas film resistance were shown to be negligible. The steel monolith support provides good mechanical strength and excellent thermal conductivity for the 13X films. The combination of properties makes this adsorbent a good performer when compared with other types of structured zeolite adsorbents in reported literatures. This microchannel adsorbent is a promising alternative to traditional adsorbents in processes of fast CO2 separation with short cycle times.

  • 9.
    Hedlund, Jonas
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Zhou, Ming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Faisal, Abrar
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Öhrman, Olov G.W.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. RISE Energy Technology Center, Box 726, 941 28, Piteå, Sweden.
    Finelli, Valeria
    Department of Chemistry, NIS and INSTM Reference Centre, Università di Torino, Via G. Quarello 15, I-10135 and Via P. Giuria 7, I-10125, Torino, Italy.
    Signorile, Matteo
    Department of Chemistry, NIS and INSTM Reference Centre, Università di Torino, Via G. Quarello 15, I-10135 and Via P. Giuria 7, I-10125, Torino, Italy.
    Crocellà, Valentina
    Department of Chemistry, NIS and INSTM Reference Centre, Università di Torino, Via G. Quarello 15, I-10135 and Via P. Giuria 7, I-10125, Torino, Italy.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Controlling diffusion resistance, selectivity and deactivation of ZSM-5 catalysts by crystal thickness and defects2022In: Journal of Catalysis, ISSN 0021-9517, E-ISSN 1090-2694, Vol. 410, p. 320-332Article in journal (Refereed)
    Abstract [en]

    A systematic investigation of two sets of defect free and defective ZSM-5 crystals with controlled thickness (T) between 30 and 400 nm and of their performances in methanol conversion was reported for the first time in the present work. The defect free ZSM-5 crystals with a thickness of 35 nm are by far the smallest ever reported and displayed superior activity, stability and selectivity to slower diffusing compounds, which resulted in high yield of e.g. gasoline and the 1,2,4-trimethylbenzene isomer with high octane number, as compared to the other studied catalysts. Almost only products forming in the zeolite pores were detected and consequently, the external surface must be nearly inactive. Strong correlations between T and deactivation rate were observed. Thick crystals deactivated much faster than thin crystals, probably due to formation of carbon species in the zeolite pores, which results in pronounced percolation effects and faster deactivation of the former. At comparable thickness, crystals with defects deactivated much faster than defect free crystals, due to formation of additional small molecular coke species in the former. Strong correlations between T and selectivity were also observed and assigned to control of diffusion resistance by crystal thickness.

  • 10.
    Korelskiy, Danil
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Ye, Pengcheng
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Zhou, Ming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    A study of CO2/CO separation by sub-micron b-oriented MFI membranes2016In: RSC Advances, E-ISSN 2046-2069, Vol. 6, no 70, p. 65475-65482Article in journal (Refereed)
    Abstract [en]

    Separation of CO2 and CO is of great importance for many industrial applications. Today, CO2 is removed from CO mainly by adsorption or physical or chemical absorption systems that are energy-intensive and expensive. Membranes are listed among the most promising sustainable and energy-efficient alternatives for CO2 separation. Here, we study CO2/CO separation by novel sub-micron b-oriented MFI zeolite membranes in a temperature range of 258-303 K and at a feed pressure of 9 bar. Under all experimental conditions studied, the membranes were CO2-selective and displayed high CO2 permeance ranging from 17 000 to 23 000 gpu. With decreasing temperature, the CO2/CO selectivity was increasing, reaching a maximum of 26 at 258 K. We also developed a mathematical model to describe the membrane process, and it indicated that the membrane separation performance was a result of selective adsorption of CO2 on the polar zeolite. The heat of adsorption of CO2 on the zeolite is more negative due to the high quadrupole moment and polarisability of the molecule as compared to CO. At the same time, diffusional coupling (correlation effects) at high adsorbed loadings was found to favour the overall CO2/CO selectivity of the membranes by reducing the diffusivity of the lighter CO molecule in the ca. 0.55 nm pores in the zeolite. The model also indicated that the separation performance was limited by the mass transfer resistance in the support and concentration polarisation on the feed side of the membrane.

  • 11.
    Nabavi, Mohammad Sadegh
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Mouzon, Johanne
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Zhou, Ming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Akhtar, Farid
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    MFI crystal and film growth and defects evolution: Revealed by high resolution electron microscopy: [Crecimiento de películas y cristales de MFI y evolución de defectos; revelado por microscopía electrónica de alta resolución]2022In: Boletín de la Sociedad Espanola de Ceramica y Vidrio, ISSN 0366-3175, E-ISSN 2173-0431, Vol. 61, no 5, p. 439-452Article in journal (Refereed)
    Abstract [en]

    Mechanism of MFI film growth from seed crystals and evolution of defects during the film growth were investigated. The hydrothermal growth of colloidal silicalite-1 crystals of 50 nm on silicon substrate was used to reveal the MFI film formation mechanism at different time intervals using high resolution-transmission electron microscopy (HR-TEM) and extreme high resolution-scanning electron microscopy (XHR-SEM). It was found that the MFI seeds started to grow in the early stages of hydrothermal treatment from 50 nm to 75 nm in size and connect to the crystals in the vicinity, showing the onset of film formation. The film growth mechanism was led by the sub-colloidal particles in the synthesis solution arriving at the crystal surfaces contributing to the film growth. A continuous film with a thickness of 100 nm was formed after 12 h of hydrothermal treatment containing pinhole defects. Pinhole defects disappeared after 24 h of hydrothermal treatment with a film thickness of 200 nm and grain boundaries thickness of 2 nm were formed. Furthermore, mesoporous defects were found in the grains of the film, which appeared due to the film growth by sub-colloidal particles of synthesis solution. The growth rate of the MFI film was calculated to 0.007 (μm/h) and compared with the crystal growth inside the synthesis solution.

    Download full text (pdf)
    fulltext
  • 12.
    Nabavi, Mohammad Sadegh
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Zhou, Ming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Mouzon, Johanne
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Stability of colloidal ZSM-5 catalysts synthesized in fluoride and hydroxide media2019In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 278, p. 167-174Article in journal (Refereed)
    Abstract [en]

    ZSM-5 zeolite crystals with carefully controlled thicknesses in the range 20–110 nm, i.e. in the colloidal domain, were synthesized in fluoride and hydroxide media. The crystals were treated in steam at high temperature to evaluate the stability and evaluated by SEM, XRD, NMR and NH3-TPD. The results showed that the framework of crystals synthesized in fluoride media was more stable than the framework of crystals synthesized in hydroxide media. This should be an effect of lower concentration of structural defects and silanol groups in the former zeolites as reported by other groups. However, independently of the synthesis conditions, all crystals dealuminated rapidly when treated with steam at the conditions investigated in the present work.

  • 13.
    Thoresen, Petter Paulsen
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Fahrni, Jonas
    RISE Processum AB, Department Biorefinery and Energy, Division of Bioeconomy and Health, Research Institute of Sweden, 981 22 Örnsköldsvik, Sweden.
    Lange, Heiko
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering. Department of Earth and Environmental Sciences, University of Milano-Bicocca, Piazza della Scienza 1, 20126 Milan, Italy; NBFC – National Biodiversity Future Center, 90133 Palermo, Italy.
    Hertzog, Jasmine
    Université de Lorraine, LCP-A2MC, 57000 Metz, France.
    Carre, Vincent
    Université de Lorraine, LCP-A2MC, 57000 Metz, France.
    Zhou, Ming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Trubetskaya, Anna
    Department of Bioscieces, Nord University, 7713 Steinkjer, Norway.
    Aubriet, Frederic
    Université de Lorraine, LCP-A2MC, 57000 Metz, France.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Gustafsson, Tomas
    RISE Processum AB, Department Biorefinery and Energy, Division of Bioeconomy and Health, Research Institute of Sweden, 981 22 Örnsköldsvik, Sweden.
    Rova, Ulrika
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Christakopoulos, Paul
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Matsakas, Leonidas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    On the understanding of bio-oil formation from the hydrothermal liquefaction of organosolv lignin isolated from softwood and hardwood sawdust2023In: Sustainable Energy & Fuels, E-ISSN 2398-4902, Vol. 7, no 22, p. 5361-5373Article in journal (Refereed)
    Abstract [en]

    Conversion of organosolv lignins isolated with and without an inorganic acid catalyst (H2SO4) from hard- and softwood (birch and spruce) into bio-oil through hydrothermal liquefaction has been investigated. Furthermore, fractions of the isolated bio-oils were catalytically deoxygenated to improve the bio-oil properties. As elucidated through NMR, both biomass source and extraction mode influence the bio-oil product distribution. Depending on whether the lignins carry a high content of native structures, or are depolymerized and subsequently condensed in the presence of sugar dehydration products, will dictate heavy oil (HO) and light oil (LO) distribution, and skew the HO product composition, which again will influence the requirements upon catalytical deoxygenation.

    Download full text (pdf)
    fulltext
  • 14.
    Yu, Liang
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Zhou, Ming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Highly permeable CHA membranes prepared by fluoride synthesisfor efficient CO2/CH4 separation2018In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 6, no 16, p. 6847-6853Article in journal (Refereed)
    Abstract [en]

    All-silica CHA nanocrystals, much smaller (20–200 nm) than previously reported, were prepared by an improved method developed in the present work. The nanocrystals are prepared by adding milled crystals to a fluoride synthesis mixture and we observed that much smaller crystals are obtained by adding a much higher fraction of milled crystals. In the next step, CHA membranes with a thickness of ca. 1.3 μm were prepared by hydrothermal treatment of a monolayer of nanocrystals supported on porous graded alumina discs in a fluoride synthesis gel. Finally, the membranes were calcined at 480 °C. The highest measured single gas CO2 permeance was 172 × 10−7 mol m−2 s−1 Pa−1 at room temperature. The highly permeable membranes were evaluated for separation of CO2 from an equimolar mixture with CH4 at varying temperatures. The highest observed CO2 mixture permeance was 84 × 10−7 mol m−2 s−1 Pa−1 at 276 K with a separation selectivity of 47 at 9 bar feed pressure and atmospheric permeate pressure. At room temperature, the CO2 mixture permeance was also as high as 78 × 10−7 mol m−2 s−1 Pa−1 with a separation selectivity of 32. To the best of our knowledge, these CO2 permeances are by far the highest reported for CHA membranes, while the selectivity is similar to that reported previously at comparable test conditions.

  • 15.
    Yu, Liang
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Kyriazidou, Iliana
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Zhou, Ming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Highly permeable DDR membranes2023In: Journal of Membrane Science, ISSN 0376-7388, E-ISSN 1873-3123, Vol. 687, article id 122039Article in journal (Refereed)
    Abstract [en]

    In this study, DDR membranes with a layer thickness of approximately 700 nm were studied for separation feeds comprising mixtures of CO2 and CH4. The membranes displayed the highest CO2 over CH4 permselectivity and CO2 permeability reported in literature. This was ascribed to a defect-free and ultra-thin zeolite film as well as an open and highly permeable support. For equimolar mixtures, the highest CO2 over CH4 permselectivity of 727 was observed when the pressure at the feed side was 5 bar(a) and the permeate pressure was 1 bar(a) at 25 °C. At these conditions, the CO2 permeability was very high at 45 × 10−7 mol/(m2 s Pa). Separation experiments for 80/20 and 20/80 mixtures were also performed, and in these cases, CO2 over CH4 permselectivities of 1011 and 622 were observed, respectively. For all feeds, the membrane permselectivity decreased slightly at higher temperature and in all cases, higher permselectivity was observed when vacuum was applied at the permeate side. One-stage membrane processes for upgrading biogas to biomethane at three different operating pressures were designed based on the experimental data. In all cases, a quite low membrane area, methane slip and power need were observed.

    Download full text (pdf)
    fulltext
  • 16.
    Zhang, Qian
    et al.
    State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, 135 Ya Guan Road, Jinnan District, Tianjin, 300350, China.
    Zhou, Ming
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Liu, Xiufeng
    State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, 135 Ya Guan Road, Jinnan District, Tianjin, 300350, China.
    Zhang, Baoquan
    State Key Laboratory of Chemical Engineering, School of Chemical Engineering and Technology, Tianjin University, 135 Ya Guan Road, Jinnan District, Tianjin, 300350, China.
    Pebax/two-dimensional MFI nanosheets mixed-matrix membranes for enhanced CO2 separation2021In: Journal of Membrane Science, ISSN 0376-7388, E-ISSN 1873-3123, Vol. 636, article id 119612Article in journal (Refereed)
    Abstract [en]

    Zeolite crystals as inorganic fillers were widely applied in fabricating mixed matrix membranes (MMMs) for CO2 separation. The poor filler-matrix interaction and the aggregation of high-loaded fillers in MMMs restrict their advantage of overcoming the trade-off limitation between permeability and selectivity. The novel MMMs with two-dimensional (2D) MFI nanosheets as inorganic fillers and Pebax MH 1657 as the matrix were synthesized and applied to achieve an efficient separation of CO2/CH4 gas mixture for the first time. The large interfacial contact areas between MFI nanosheets and Pebax matrix improve their compatibility to form defect-free MMMs with better mechanical properties. The high-aspect-ratio MFI nanosheets function as solid and selective barriers to make MMMs possess a significant promotion in both CO2 permeability and CO2/CH4 selectivity without the trade-off limitation. The MMM containing 5 wt% of MFI nanosheets exhibited the optimum performance with CO2 permeability of 159.1 Barrer and CO2/CH4 selectivity of 27.4. The as-prepared MMMs showed an improvement of 63.5% in CO2 permeability and 76.4% in CO2/CH4 selectivity, compared to pristine Pebax membranes.

  • 17.
    Zhou, Ming
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Bodenmuller, Niklas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Enhanced bio-oil upgrading by sub-microscale dispersed silanol-free ZSM-5 nanosheets and evidence for revealing an unconventional mechanism2023In: Chemical Engineering Journal, ISSN 1385-8947, E-ISSN 1873-3212, Vol. 478, article id 147457Article in journal (Refereed)
    Abstract [en]

    Silanol-free ZSM-5 nanosheet with merely 35 nm thickness in the b-axis was synthesized by seeded growth from defect-free 10 nm silicalite-1 in a fluoride medium (denoted as F35). Submicron-scaled stöber sol silica beads were introduced into the gap between nanosheets to serve as a spacer for the prevention of neighboring crystals' close contact with each other, which can improve the heat and mass transportation during the catalytic reactions when compared to the aggregated zeolite crystals. Methanol-to-hydrocarbons (MTH) and model bio-oil upgrading were conducted by using dispersed F35, respectively, and the results were compared to the aggregated ZSM-5. The effluent from bio-oil upgrading through dispersed F35 contains no heavier compound, which was considered as the coke precursor, and significantly reduced amount of unreacted feeding molecule. GC–MS revealed that the coke solution from dispersed F35 contains a considerably reduced (61 %) amount of heavier carbon species. Among them, some species have molecular configurations highly consistent with the zeolite channel structure. The dispersed F35 shows a 33 % longer life in catalytic reactions and a 60 % decreased amount of external thermal cock. An unconventional ‘temperature-determined flexible channel’ mechanism that explains the ‘host–guest’ interactive behavior under catalytic reaction was proposed.

    Download full text (pdf)
    fulltext
  • 18.
    Zhou, Ming
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Zhou, Han
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Holmgren, Allan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    The facile assembly of nanocrystals by optimizing humidity2014In: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, Vol. 50, no 91, p. 14261-14264Article in journal (Refereed)
    Abstract [en]

    The ambient humidity and the nature of substrates are considered coordinately in the assembly of nano-sized crystals. The nanocrystal monolayers show large-area uniformity without any aggregates. Zeolite and hematite monolayers with thicknesses of 20–100 nm and excellent orientations are produced.

  • 19.
    Zhou, Ming
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Assembly of oriented iron oxide and zeolite crystals via biopolymer films2012In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 22, no 47, p. 24877-24881Article in journal (Refereed)
    Abstract [en]

    Biopolymers are developed as functional intermediate linkers for the assembly of nano and submicron-sized crystals. Mediated by the interlayers, iron oxide and zeolite crystals with varied shapes (cubic, ellipsoidal, and discoidal) are organized into uniformly oriented monolayers on glass plates and macroporous alumina supports. The crystal monolayers can be near-perfect transferred onto the substrate upon calcination, which are suitable for further growth. The assembled crystals display a range of colors, and important mechanisms with direct evidence for explaining this optical appearance are proposed.

  • 20.
    Zhou, Ming
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Facile Preparation of Hydrophobic Colloidal MFI and CHA Crystals and Oriented Ultra-thin Films2018In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 130, no 34, p. 11132-11136Article in journal (Refereed)
    Abstract [en]

    We report novel routes for synthesis of defect-free, hydrophobic and monodispersed 10 nm (5 unit cells) thick MFI crystals and 100 nm CHA crystals. The crystals are obtained in high yield and display very high 1-butanol adsorption from aqueous solution. These crystals are assembled in monolayers for the growth of ultra-thin and uniformly oriented films with thicknesses of 36 nm and 330 nm, respectively, using a synthesis gel in the form of a powder. This method is very simple and may open up for industrial preparation of materials with improved performances.

  • 21.
    Zhou, Ming
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Oriented monolayers of submicron crystals by dynamic interfacial assembly2012In: Journal of Materials Chemistry, ISSN 0959-9428, E-ISSN 1364-5501, Vol. 22, no 8, p. 3307-3310Article in journal (Refereed)
    Abstract [en]

    Large-area, void-free monolayers of oriented submicron crystals (silicalite-1, 800 nm and hematite, 400 nm) were fabricated on an air-water interface by dynamic interfacial assembly and were transferred onto solid substrates with different properties (porous, hydrophobic, conductive

  • 22.
    Zhou, Ming
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Khokarale, Santosh Govind
    Department of Chemistry, Chemical-Biological Centre (KBC), Umeå University, Umeå, Sweden.
    Balsamo, Marco
    Dipartimento di Scienze Chimiche, Università degli Studi di Napoli Federico II, Napoli, Italy.
    Mikkola, Jyri-Pekka
    Department of Chemistry, Chemical-Biological Centre (KBC), Umeå University, Umeå, Sweden. Industrial Chemistry & Reaction Engineering, Johan Gadollin Process Chemistry Centre, Åbo Akademi University, Åbo-Turku, Finland.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Oligoamine ionic liquids supported on mesoporous microspheres for CO2 separation with good sorption kinetics and low cost2020In: Journal of CO2 Utilization, ISSN 2212-9820, E-ISSN 2212-9839, Vol. 39, article id 101186Article in journal (Refereed)
    Abstract [en]

    Ionic liquids display good CO2 absorption capacity but poor absorption kinetics and high costs. In the present work, we show that these problems can be solved by impregnating the new low cost ionic liquid pentaethylenehexammonium chloride [PEHA][Cl] and the corresponding amine precursor on a low cost mesoporous microsphere support. Nitrogen adsorption/ desorption, high-resolution SEM and thermogravimetric analysis were employed to analyze the structural and thermal properties of the prepared sorbents. The CO2 adsorption and desorption performance was studied by column experiments and mathematical models were fitted to the data. The results showed that sorbents displayed excellent sorption kinetics and capacity, comparable to the best reports in the literature. In addition, the sorbents could be regenerated and displayed high thermal stability. Finally, the costs of the sorbents developed in the present work is much lower than previously reported sorbents. Therefore this novel supported IL system could be promising for industrial CO2 removal and recovery applications.

  • 23.
    Zhou, Ming
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Korelskiy, Danil
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Ye, Pengcheng
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    A Uniformly Oriented MFI Membrane for Improved CO2 Separation2014In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 53, no 13, p. 3492-3495Article in journal (Refereed)
    Abstract [en]

    Membrane separation of CO2 from natural gas, biogas, synthesis gas, and flu gas is a simple and energy-efficient alternative to other separation techniques. But results for CO2-selective permeance have always been achieved by randomly oriented and thick zeolite membranes. Thin, oriented membranes have great potential to realize high-flux and high-selectivity separation of mixtures at low energy cost. We now report a facile method for preparing silica MFI membranes in fluoride media on a graded alumina support. In the resulting membrane straight channels are uniformly vertically aligned and the membrane has a thickness of 0.5m. The membrane showed a separation selectivity of 109 for CO2/H-2 mixtures and a CO2 permeance of 51x10(-7)molm(-2)s(-1)Pa(-1) at -35 degrees C, making it promising for practical CO2 separation from mixtures

  • 24.
    Zhou, Ming
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Korelskiy, Danil
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Ye, Pengcheng
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    A Uniformly Oriented MFI Membrane for Improved CO2 Separation2014In: Angewandte Chemie, ISSN 0044-8249, Vol. 126, no 13, p. 3560-3563Article in journal (Refereed)
    Abstract [en]

    Membrane separation of CO2 from natural gas, biogas, synthesis gas, and flu gas is a simple and energy-efficient alternative to other separation techniques. But results for CO2-selective permeance have always been achieved by randomly oriented and thick zeolite membranes. Thin, oriented membranes have great potential to realize high-flux and high-selectivity separation of mixtures at low energy cost. We now report a facile method for preparing silica MFI membranes in fluoride media on a graded alumina support. In the resulting membrane straight channels are uniformly vertically aligned and the membrane has a thickness of 0.5 μm. The membrane showed a separation selectivity of 109 for CO2/H2 mixtures and a CO2 permeance of 51×10−7 mol m−2 s−1 Pa−1 at −35 °C, making it promising for practical CO2 separation from mixtures

  • 25.
    Zhou, Ming
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Nabavi, Mohammad Sadegh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Influence of support surface roughness on zeolite membrane quality2020In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 308, article id 110546Article in journal (Refereed)
    Abstract [en]

    Two main types of morphological features resulting in surface roughness were observed on alumina discs used as supports for zeolite membranes. These features can be described as hills and pits and it was shown that defects as cracks formed in the zeolite film at these locations of the support. It was demonstrated that the roughness of the support can be reduced significantly by a polishing strategy developed in this paper. Finally, zeolite MFI membranes grown on the polished support shows remarkably improved quality as compared to films grown on non-polished supports.

  • 26.
    Zhou, Ming
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Rownaghi, Ali
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Synthesis of mesoporous ZSM-5 zeolite crystals by conventional hydrothermal treatment2013In: RSC Advances, E-ISSN 2046-2069, Vol. 3, no 36, p. 15596-15599Article in journal (Refereed)
    Abstract [en]

    Well-defined ZSM-5 crystals with tablet habit, uniform size, controllable silica/alumina ratio, and high mesoporosity were prepared using conventional hydrothermal treatment under stirring. The key to obtaining high mesoporosity of the crystals was to stir a synthesis mixture containing a relatively high concentration of alumina

  • 27.
    Zhou, Ming
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Yu, Liang
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Ultrathin DDR Films with Exceptionally High CO2 Flux and Uniformly Adjustable Orientations2022In: Advanced Functional Materials, ISSN 1616-301X, E-ISSN 1616-3028, Vol. 32, no 18, article id 2112427Article in journal (Refereed)
    Abstract [en]

    Thin and oriented zeolite films are important for advanced separations, catalysis, and sensing. Strategies for tailoring zeolites for applications include controlling their crystal size, shape, and orientation. Here, three siliceous DDR zeolite ultrathin films with different orientations achieved by homoepitaxial growth from 60 nm-sized seed particles are reported. The 0.5 µm thick membrane shows a separation selectivity of 400 for CO2–CH4 mixtures and CO2 permeance of 25 × 10-7 mol m-2 s-1 Pa-1 at 20 °C and 1 bar, leading to a record-high performance among all reported DDR membranes. Furthermore, the seed nanoparticles are grown into mono-dispersed DDR sub-micron crystals with trigonal and tabular habits. These crystals are assembled in monolayers for the growth of ultrathin and uniformly (h0h)-oriented and c-oriented films with maximum surface pore diameter of 0.365 and 0.263 nm, respectively, by using the 1-adamantanamine template in fluoride medium. The novel strategy not only provides high-performance membrane candidates for industrial CO2 separation, but also inspires interfacial engineering, pore size, and orientation controlling for other microporous crystals, and their membranes.

1 - 27 of 27
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association-8th-edition
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf