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  • 1.
    Butylina, Svetlana
    et al.
    Department of Chemical Technology, Lappeenranta University of Technology.
    Shataeva, Larisa K.
    bInstitute of Macromolecular Compounds, Russian Academy of Science.
    Nyström, Marianne
    Department of Chemical Technology, Lappeenranta University of Technology.
    Separation of nucleoprotein complexes with antioxidant activity from yeast Saccharomyces cerevisiae2007In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 53, no 1, p. 64-70Article in journal (Refereed)
    Abstract [en]

    In this study, complexes of nucleic acids and acidic nuclear proteins were isolated from baker's yeast cells of Saccharomyces cerevisiae by mild alkaline extraction followed by precipitation with acetic acid. The optimal composition of the buffer applied for extraction of nucleoprotein complexes was determined. The high and low molar mass fractions of the nucleoprotein complexes were separated using cross-flow microfiltration through track-etched membranes. The molar masses were determined by intrinsic viscosity measurements and the molar mass distribution in nucleoprotein complexes was studied by gel permeation chromatography. The protein component of the nucleoprotein complexes was purified on a strongly basic anion exchange resin. The high molar mass nucleoprotein complexes could induce the growth of culture cells of S. cerevisiae exposed to ultraviolet irradiation or treated with hydrogen peroxide

  • 2.
    Jareman, Fredrik
    et al.
    Luleå University of Technology.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Sterte, Johan
    Effects of aluminum content on the separation properties of MFI membranes2003In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 32, no 1-3, p. 159-163Article in journal (Refereed)
    Abstract [en]

    MFI membranes with almost identical film thickness and defect distribution but different Si/Al ratio were evaluated by separation of butane and hexane isomers. Film thickness was evaluated by SEM and defect distribution by porosimetry. When the temperature was varied, the membranes showed similar separation trends for butanes, but clear differences were observed for hexane separation. The hexane separation factor varied with temperature for the silicalite-1 membrane but was constant for the ZSM-5 membrane. It is believed that this difference may be a result of differences in adsorption properties.

  • 3.
    Li, Biao
    et al.
    Key Laboratory of Material-Oriented and Chemical Engineering, Nanjing Tech University.
    Chen, Yifeng
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. Key Laboratory of Material and Chemical Engineering, Nanjing Tech University, Nanjing .
    Yang, Zhuhong
    Key Laboratory of Material and Chemical Engineering, Nanjing Tech University, Nanjing .
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Lu, Xiaohua
    Key Laboratory of Material and Chemical Engineering, Nanjing Tech University, Nanjing .
    Thermodynamic study on carbon dioxide absorption in aqueous solutions of choline-based amino acid ionic liquids2019In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 214, p. 128-138Article in journal (Refereed)
    Abstract [en]

    Five choline-based amino acid ionic liquids ([Cho][AA]s) are prepared by neutralization between choline hydroxide and amino acids with different molecular weight and alkalinity. Solubility of CO2 in 30 wt% aqueous solutions of these five [Cho][AA]s has been measured at temperatures from 303.15 to 333.15 K and pressures up to 7 bar. Based on the zwitterion mechanism, the solubility of CO2 in aqueous [Cho][AA]s solutions is correlated with a reaction equilibrium thermodynamic model (RETM). The corresponding thermodynamic parameters, such as Henry’s law constants, reaction equilibrium constants, and enthalpy of physical dissolution and chemical reaction are all calculated and compared to evaluate the CO2 absorption performance in aqueous solutions of five [Cho][AA]s. Meanwhile, the recyclability of the aqueous solution with 30 wt% [Cho][Lys] has been also investigated.

  • 4.
    Misiulia, Dzmitry
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Elsayed, Khairy
    Mechanical Power Engineering Department, Faculty of Engineering, El-Mattaria, Helwan University.
    Andersson, Anders Gustav
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Fluid and Experimental Mechanics.
    Geometry optimization of a deswirler for cyclone separator in terms of pressure drop using CFD and artificial neural network2017In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 185, p. 10-23Article in journal (Refereed)
    Abstract [en]

    Four main geometrical parameters of a deswirler (core diameter, number of vanes, height of vanes and leading edge angle) for cyclone separators have been optimized using CFD and artificial neural network. The results indicated that the most significant geometrical parameters of the deswirler are the number of vanes, the vane angle and the vane height. A new optimized deswirler geometry was obtained using the genetic algorithms and its effects on the flow field, pressure losses and cyclone collection efficiency were numerically investigated. The deswirler positively affects the flow field within a cyclone. It dramatically reduces tangential velocities in the vortex finder and only slightly (by 4.5%) decreases maximum tangential velocities in the separation zone. The deswirler also reduces the length of the inner vortex, redistributes uniformly axial velocities at the vortex finder outlet and prevents backward flow. Additionally, the deswirler converts the dynamic energy of the swirling flow into pressure and allows pressure recovery. It reduces pressure losses in the vortex finder by 95.67% that leads to 43.17% reduction in total pressure drop and slightly decreases the separation efficiency for some particle diameters, increasing the cyclone cut size from 1.5 to 1.72 μm.

  • 5.
    Nazari, S.
    et al.
    University of Tehran, Tehran, Iran.
    Chelgani, Saeed Chehreh
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Minerals and Metallurgical Engineering.
    Shafaei, S.Z.
    University of Tehran, Tehran, Iran.
    Shahbazi, B.
    Tarbiat Modares University, Tehran, Iran.
    Matin, S.S.
    University of Technology Sydney, Sydney, Australia.
    Gharabaghi, A.
    University of Tehran, Tehran, Iran.
    Flotation of coarse particles by hydrodynamic cavitation generated in the presence of conventional reagents2019In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 220, p. 61-68Article in journal (Refereed)
    Abstract [en]

    Hydrodynamic cavitation (HC) (typically used to generate submicron bubbles) are frequently examined to improve froth flotation efficiency of ultrafine particles (−38 µm); however, the study of their effects on flotation parameters during the process of coarse particles (+100 µm) was not significantly explored. The main aim of this investigation is to discover the impacts of HC on effective flotation variables and flotation recovery of coarse particles (FRCP). Various surfactants (frothers: Methyl isobutyl carbinol (MIBC) and pine oil (PO), and dodecyl amine (DDA)) were used for the HC conditions. For comparison purposes, two series of flotation experiments in the absence and presence of HC were conducted by using coarse pure quartz particles (−425 + 106 µm). Variable importance measurements (VIMs) of random forest were applied to compare and assess impacts of flotation parameters (particle size, flotation conventional bubble (CB) size, impeller speed, and air flow rate) on FRCP in the absence and presence of HC. Outputs of VIMs indicated that the negative effect of particle size on FRCP was decreased and the capability of CB for floating coarse particles was improved in the presence of HC. Moreover, VIM results showed that in the presence of HC, the highest FRCP can be achieved when turbulent is lower. Generally, variations in the airflow rate had negligible impacts on FRCP. Flotation experiments suggested that HC in the presence of the collector can overcome the absence of frothers in a flotation system. These results can be used for enhancement of selective separation via froth flotation.

  • 6.
    Rezaei, Fateme
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Mosca, Alessandra
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Webley, P.A.
    Monash University, Melbourne, VIC.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Mouzon, Johanne
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    The effect of wall porosity and zeolite film thickness on the dynamic behavior of adsorbents in the form of coated monoliths2011In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 81, no 2, p. 191-199Article in journal (Refereed)
    Abstract [en]

    The effects of wall porosity, channel width distribution and zeolite film thickness on the performance of 400 and 1200 cells per square inch (cpsi) cordierite monoliths coated with zeolite X films with thicknesses of 1.5 and 2.5 μm were examined. To investigate the effect of wall porosity and restrict growth of zeolite to the external surface of the monolith channels, the macro pores in the walls of the 1200 cpsi cordierite monoliths were filled with colloidal α-alumina particles. The adsorbents were characterized by Scanning Electron Microscopy, Mercury Intrusion Porosimetry and carbon dioxide breakthrough experiments and a mathematical model describing the diffusion and adsorption in the system was fitted to the data. The model accounted for carbon dioxide uptake by filling the pores in the support by carbon dioxide gas and adsorption of carbon dioxide on cordierite, alumina and zeolite. The model indicates that the uptake of carbon dioxide by adsorption on cordierite is much slower than by pore filling and too slow to influence the very fast breakthrough experiments with monoliths without zeolite film that are over in less than 1 minute. It was shown that the pores in the cordierite monolith result in dispersion by pore filling with carbon dioxide gas, not adsorption. The CO2 adsorption capacity of a 1200 cpsi monolith coated with a 2.5 μm film was 0.13 mmol/cm3 adsorbent, which should be compared to the adsorption capacity of zeolite X beads, which is about 2.3 mmol/cm3 adsorbent. To increase adsorption capacity of a non-porous zeolite coated monolith, film thickness could be increased. The model indicated that the film thickness could be increased up to about 10 μm without increasing the dispersion and thereby approach the adsorption capacity for beads. However, simulation of the whole cycle must be performed in order to find the optimum film thickness for a real cyclic process. This work has lead to better understanding of the role of the support porosity and pore size distribution and film thickness for coated monolith adsorbents.

  • 7. Rezaei, Fateme
    et al.
    Webley, Paul
    Monash University, Melbourne, VIC.
    Structured adsorbents in gas separation processes2010In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 70, p. 243-256Article in journal (Refereed)
  • 8.
    Yu, Liang
    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.
    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.
    Very High Flux MFI Membranes for Alcohol Recovery via Pervaporation at High Temperature and Pressure2015In: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 153, p. 138-145Article in journal (Refereed)
    Abstract [en]

    Ultra-thin MFI membranes (0.5 μm) were evaluated for recovery of alcohols from dilute aqueous mixtures by pervaporation at high temperature and pressure for the first time. The feed pressure was sufficiently high to keep the feed in liquid state at high temperature, while the permeate pressure was kept at atmospheric and a low flow of sweep gas was used to reduce the partial pressure on the permeate side. Atmospheric pressure on the permeate side is more practical than vacuum. High feed temperature and pressure result in high fugacity in the liquid feed, which, in combination with lower permeate pressure, results in a large driving force. Consequently, the membrane exhibited very high fluxes for feeds comprised of 10 wt% ethanol/water and 5 wt% n-butanol/water mixtures at 110 °C and 140 °C, respectively. The flux observed for 10 wt% ethanol/water mixtures was as high as about 52 kg m-2 h-1, i.e., 6 times higher than the highest previously reported flux for this separation using zeolite membranes in pervaporation. For 5 wt% n-butanol/water mixtures, the flux was 40 kg m-2 h-1, which is 11 times higher than the highest previously reported flux for this separation by zeolite membranes. At these conditions, the membrane displayed separation factors for ethanol/water and n-butanol/water mixtures of 5 and 16, respectively. However, after about 6 hours of operation, the separation factor decreased significantly and the flux increased due to formation of defects in the membrane when the feed was saturated with silica. Lower membrane stability was observed for silica free feeds. The work has shown that it is possible to obtain high flux in pervporation by using ultra-thin membranes in combination with high feed temperature. The observed membrane selectivity was not excellent, due to pressure drop over the support as well as likely concentration polarization on the feed side resulting from the high flux. Membrane stability was also an issue at these conditions, however it was shown that stability could be improved by saturating the feed with silica.

1 - 8 of 8
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