Change search
Refine search result
1 - 10 of 10
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • 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.
    Abdel-Magied, Ahmed F.
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Nasser Abdelhamid, Hani
    Ashour, Radwa M.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering.
    Zou, Xiaodong
    Forsberg, Kerstin
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Resource recovery.
    Hierarchical porous zeolitic imidazolate framework nanoparticles for efficient adsorption of rare-earth elements2019In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 278, p. 175-184Article in journal (Refereed)
    Abstract [en]

    Hierarchical porous zeolitic imidazolate frameworks nanoparticles (ZIF-8 NPs) were synthesized at room temperature via a template-free approach under dynamic conditions (stirring) using water as a solvent. The ZIF-8 NPs were evaluated as adsorbents for rare earth elements (La3+, Sm3+ and Dy3+). Adsorption equilibrium was reached after 7h and high adsorption capacities were obtained for dysprosium and samarium (430.4 and 281.1 mg g(-1), respectively) and moderate adsorption capacity for lanthanum (28.8 mg g(-1)) at a pH of 7.0. The high adsorption capacitiese, as well as the high stability of ZIF-8 NPs, make the hierarchical ZIF-8 materials as an efficient adsorbent for the recovery of La3+, Sm3+ and Dy3+ from aqueous solution.

  • 2.
    Al-Soubaihi, Rola
    et al.
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Saoud, K. M.
    Virginia Commonwealth University in Qatar, Libral Arts and Sciences Program, P.O. Box 8095, Doha, Qatar.
    Fei, Ye
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Zar Myint, M. T.
    Department of Physics, College of Science, Sultan Qaboos University, P.O. Box 36, Muscat, PC 123, Oman.
    Saeed, S.
    Department of Chemistry, Paksitan Institute of Engineering and Applied Sciences (PIEAS), PO Nilore, Islamabad, 45650, Pakistan.
    Dutta, Joydeep
    KTH, School of Engineering Sciences (SCI), Applied Physics.
    Synthesis of hierarchically porous silica aerogel supported Palladium catalyst for low-temperature CO oxidation under ignition/extinction conditions2020In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 292, article id 109758Article in journal (Refereed)
    Abstract [en]

    Synthesis of well-dispersed palladium nanoparticles within silica aerogel pores with controlled size was carried out using sol-gel synthesis under supercritical ethanol drying. The high concentration of silanol groups on silica (SiO2) surface facilitated a superior palladium (Pd) loading up to 10 wt %. The synthesized Pd/SiO2 nanocomposite aerogels were characterized by X-ray diffraction (XRD), N2 adsorption-desorption, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and Fourier transform infrared (FTIR) spectroscopic methods. The silica aerogel supported catalysts were found to have a wide pore size distribution. TEM investigations confirmed that Pd nanocrystals were located within the SiO2 microspores and mesopores. The catalyst was evaluated for carbon monoxide (CO) oxidation reaction under ignition/extinction conditions. The synthesized catalyst demonstrated a high catalytic activity at low operating temperatures (<200 °C) compared to unsupported Pd nanoparticles or bare SiO2 aerogels. This enhancement in CO oxidation activity with Pd/SiO2 aerogel catalysts are attributed to the small Pd particles, Pd interaction with the surface of the underlying SiO2 and the better dispersion of Pd particles within the SiO2 pores. Porosity played a more important role during the extinction cycle as a result of the slow dissipation of the heat leading to hysteresis. We demonstrate the influence of porosity of catalyst supports on the size, dispersion, and catalytic activity of Pd nanoparticles.

  • 3. Filippov, Andrei
    et al.
    Azancheev, Nail
    Shah, Faiz Ullah
    Glavatskih, Sergei
    KTH, School of Industrial Engineering and Management (ITM).
    Antzutkin, Oleg N.
    Self-diffusion of phosphonium Bis(Salicylato)Borate ionic liquid in pores of Vycor porous glass2016In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 230, p. 128-134Article in journal (Refereed)
    Abstract [en]

    H-1 NMR pulsed field gradient was used to study self-diffusion of a phosphonium bis(salicylato)borate ionic liquid ([P6,6,6,14][BScB]) in the pores of Vycor porous glass at 296 K. Confinement in pores increases diffusion coefficients of the ions by a factor of 35. However, some [P6,6,634][BScB] ions demonstrated apparent diffusion coefficients much lower than their mean values, which may be due to partially restricted diffusion of the ions. We suggest that this fraction corresponds to areas where ions are confined by pore 'necks' (micropores) and empty voids. Heating of the ionic liquid/Vycor system at 330 K led to a change in the diffusivity of the ions, because of their redistribution in the pores. The size of the bounded regions is on the order of 1 mu m, as estimated from the dependence of the ion diffusivity on the diffusion time.

  • 4.
    Hussami, Linda
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Inorganic Chemistry.
    Corkery, Robert W.
    Institute for Surface Chemistry.
    Kloo, Lars
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Inorganic Chemistry.
    Study of [Dy(eta(6)-p-xylene)(GaCl4)(3)]-incorporated polyhedral silica nanofoam2010In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 132, no 3, p. 480-486Article in journal (Refereed)
    Abstract [en]

    Preparation and characterization of organometallic dysprosium complex embedded polyhedral silica nanofoam (PNE-SiO2) is reported. The nanoporous solid was obtained via a sol-gel process involving precipitation of polymer micelles, hydrolysis and condensation of silica by swelling of triblock copolymer template micelles of PEO-PPO-PEO at acidic pH using high oil concentration and fast stirring. Metal-complex incorporation was performed via wet impregnation (WI) at higher temperature, where the dysprosium complex is chemically bound to the silanol groups of the silica foam surface. Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS) revealed that the particles of the organometallic complex are evenly distributed on the walls of the polyhedral cells, while nitrogen adsorption/desorption measurements (BET) verified that the characteristic meso- and macrocell structure of PNE-SiO2 composed of polyhedral cells of silica joined at mesosized windows are preserved also after incorporation.

  • 5.
    Kaali, Peter
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Strömberg, Emma
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Aune, Ragnhild E.
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Materials Process Science.
    Karlsson, Sigbritt
    KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
    Czel, Gyorgy
    Modelling the ion distribution in single, binary and ternary ion exchanged Azeolite2011In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093Article in journal (Other academic)
  • 6.
    Najmoddin, Najmeh
    et al.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Beitollahi, Ali
    Devlin, Eamonn
    Kavas, Huseyin
    Mohseni, Seyed Majid
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics.
    Åkerman, Johan
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Material Physics, MF.
    Niarchos, Dimitris
    Rezaie, Hamidreza
    Muhammed, Mamoun
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Toprak, Muhammet S.
    KTH, School of Information and Communication Technology (ICT), Materials- and Nano Physics, Functional Materials, FNM.
    Magnetic properties of crystalline mesoporous Zn-substituted copper ferrite synthesized under nanoconfinement in silica matrix2014In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 190, p. 346-355Article in journal (Refereed)
    Abstract [en]

    A series of ordered mesoporous single phase Cu1-xZnxFe2O4 spinel ferrites, with x ranging from 0.00 to 0.75 with a step increment of 0.25, are prepared by a novel nanocasting route with the aid of vinyl-functionalized mesoporous silica as a hard template. All samples display a relatively high surface area and narrow pore size distribution from nitrogen sorption analysis. The magnetic hysteresis loops of these samples measured at 300 K, the temperature dependence of the zero field cooled (ZFC) and field cooled (FC) magnetization curves and the Mossbauer Spectra show the presence of superparamagnetic nanopartides in all samples. The hysteresis data indicate that the maximum saturation magnetization of 52 emu g(-1), is obtained for the composition with x = 0.25. For x >= 0.5, the saturation magnetization decreases as a result of the cation redistribution within tetrahedral (A) and octahedral (B) sites which weakens the A-B interactions due to triangular Yafet-Kittel spin arrangement on the B-sublattice. The observed magnetic features are attributed to the confined spaces of the host material which acts as a nanoreactor, limiting the growth of the embedded oxide phase and significantly influencing the cation distribution of copper-zinc ferrite on the A and B sites.

  • 7.
    Petrov, Oleg
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Industrial NMR Centre.
    Furó, Istvan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Industrial NMR Centre.
    A study of freezing-melting hysteresis of water in different porous materials. Part I: Porous silica glasses2011In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 138, no 1-3, p. 221-227Article in journal (Refereed)
    Abstract [en]

    The freezing and melting temperature hysteresis of water in Vycor porous glass and controlled pore glass (CPG) with the nominal pore diameters 7.0 and 7.5 nm, respectively, has been explored by NMR cryoporometry and NMR relaxometry techniques. The freezing branch of the hysteresis in Vycor was found to be much steeper than the melting one, presumably due to the pore blocking on freezing. This is not observed in CPG, which exhibits parallel freezing and melting branches. Sub-loops recorded starting from partially frozen states are self-similar with respect to the amount of unfrozen water, in both CPG and Vycor. On the other hand, sub-loops starting from partially molten states are self-similar only in CPG, while in Vycor, their shape does depend on the amount of unfrozen water. T-2 relaxation measurements undertaken along the freezing branch reveal in both glasses a slow (on an NMR timescale) exchange of water molecules between frozen and unfrozen pore domains, indicating a good segregation of those domains on freezing. On melting, however, the regime of slow exchange persists only for CPG, while in Vycor, a quasi-exponential T-2 relaxation is observed, characteristic of fast exchange. This suggests that frozen and molten regions in Vycor are well dispersed on melting, while in CPG they present extended domains. We explain such a difference assuming a worse interconnection of a Vycor's pore space as compared to CPG, taking into account its essentially lower porosity (0.28 versus 0.51 in CPG).

  • 8.
    Petrov, Oleg V.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Industrial NMR Centre.
    Furo, Istvan
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Physical Chemistry. KTH, School of Chemical Science and Engineering (CHE), Centres, Industrial NMR Centre.
    A joint use of melting and freezing data in NMR cryoporometry2010In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 136, no 1-3, p. 83-91Article in journal (Refereed)
    Abstract [en]

    Freezing and melting behaviour of water, benzene, cyclooctane and cyclohexane confined in different-sized controlled pore glasses (CPG's) has been studied by NMR cryoporometry technique. It was found that the freezing (Delta Tf) and melting (Delta Tm) temperature shifts correlate linearly, giving a constant ratio AT, Delta Tm/Delta Tf over different fluids. This suggests that the ratio is a measure of pore morphology rather than fluid's properties. The suggestion is supported by the theoretical treatment that predicts for Delta Tf to be controlled by the surface-to-volume ratio (S/V) and Delta Tm, by the pore curvature (dS/dV). Therefore, the ratio Delta Tm/Delta Tf provides one with the information on the pore shape, unavailable from Delta Tf or AT, measurements alone. For CPG samples under study, this ratio decreases from 0.67 in 7.5 nm pores, which is expected for spherical geometry, to 0.57 in 27.3 and 72.9 nm pores, which is closer to what is expected for cylindrical, or tubular, pores. The pore size distribution functions obtained from the freezing and melting data were found to be similar in shape and width, which indicates that melting and freezing processes occur in CPG on the same length scale of the pore structure.

  • 9. Sörensen, Malin H.
    et al.
    Corkery, Robert W.
    Alberius, Peter C. A.
    Control of internal (2D and 3D hexagonal) mesostructure andparticle morphology of spherical mesoporous silica particlesusing the emulsion and solvent evaporation (ESE) method2009In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 120, p. 359-367Article in journal (Refereed)
    Abstract [en]

    In this study we demonstrate the opportunities controlling internal structure as well as exterior morphology of surfactant templated mesostructured materials through the newly developed emulsion and solvent evaporation (ESE) method. In particular, we consider the control of synthesis temperature and map the influence upon both internal structure and surface morphology of particles templated by the temperature sensitive Pluronic block copolymer F127. Furthermore, we vary compositions, by adding poly(propylene glycol) acting as a swelling agent, as well as by controlling the moisture content. Both of these are having an impact on the internal mesostructure as well as the pore size. Apart from probing internal structure by scattering techniques, the accessibility of the mesoscopic pores of these materials are investigated by measuring the adsorption of a cationic dye, Janus Green B, into the materials. This method shows that accessibility varies dramatically with internal structure.Further, by carefully controlling the moisture content when using the cationic surfactant C(16)TAB as template, a well ordered 3D hexagonal closed packed (P6(3)/mmc) material with large surface area as well as pore volume was prepared. This further indicates the versatility of the new preparation technique.

  • 10.
    Sörensen, Malin H.
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemistry, Surface Chemistry (closed 20081231).
    Crokery, Robert W.
    YKI, Ytkemiska Institutet.
    Pedersen Skov, Jan
    Rosenholm, Jessica
    Alberius, Peter C.
    Expansion of the F127-templated mesostructure in aerosolgeneratedparticles by using polypropylene glycol as a swelling agent2008In: Microporous and Mesoporous Materials, ISSN 1387-1811, E-ISSN 1873-3093, Vol. 113, p. 1-13Article in journal (Refereed)
    Abstract [en]

    Expansion of the mesostructure in aerosol-generated particles was performed through incorporation of polypropylene glycol (PPG), a non-volatile swelling agent. TEOS was used as silica source and the Pluronic block copolymer, F127, as template. The ratio of TEOS to F127 was kept constant during synthesis, while varying the weight ratio of PPG to F127 systematically. The impact of the PPG on the expansion of the structure was characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and nitrogen adsorption. Different methods were used to calculate the pore size distributions, the BJH, the BdB-FHH, the KJS and the NLDFT method. Simple geometrical models of the expansion were derived to interpret the experimental data and establish their accuracy. Experimental data showed a roughly linear expansion of the unit cell and pore size, consistent with that expected by modelling the swelling of a hexagonal (p6mm) structure assuming constant wall thickness. The expansion is increasing as a function of increasing PPG/F127 ratio by about 25 Å. An expression of the density of the silica wall was calculated from the models resulting in a density of 1.95 ± 0.2 g/cm3. At a PPG/F127 ratio of approximately 0.31, the p6mm structure (found at lower PPG/F127 ratios) transforms to a microemulsion-templated foam structure. At an even higher PPG/F127 ratio (0.63–1.56), phase separation of the oil from the swollen template occurred, yielding a two-phase system of coexisting foam and large vesicles.

1 - 10 of 10
CiteExportLink to result list
Permanent link
Cite
Citation style
  • apa
  • harvard1
  • 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