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  • 1.
    Bergström, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Fiber- och polymerteknik.
    Vomhoff, Hannes
    Literature review of experimental hydrocyclone flow field studies2007Ingår i: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 53, nr 1, s. 8-20Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The complex flow field of hydrocyclones has been experimentally investigated on several occasions. Most studies present similar results for the tangential velocity component. In the inner part of the cyclone, it resembles a solid-body rotation, while it typically has a free-vortex-like behavior in the outer part. When looking at the axial velocity component, the results are more diversified. Most studies show a downward velocity close to the wall and an upward velocity in the center. However, some studies report a heavily varying axial velocity over short radii close to the centerline. The radial velocity component appears to be the most problematic one to measure. Dissimilarities in measurement results between the studies are often greater than similarities. However, later studies agree on an increasing inward radial velocity towards the hydrocyclone center. Despite the obvious relationship, extremely little experimental research work can be found in the literature where changes to the flow field are connected to changes in separation efficiency.

  • 2. Durruty, J.
    et al.
    Mattsson, T.
    Theliander, Hans
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Local filtration properties of Kraft lignin: The influence of residual xylan2017Ingår i: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 179, s. 455-466Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The influence of lignin and xylan interactions on the filtration properties of precipitated LignoBoost lignin was investigated. LignoBoost lignin was (i) suspended in acid water with xylan added and (ii) dissolved together with xylan and then re-precipitated. The resulting lignin-xylan mixtures were more difficult to filter than the original LignoBoost lignin, although the formed filter cake was also found more porous in the case of re-precipitated solids. Furthermore, the pressure dependency of the filtration properties was shown to increase after the addition of xylan. One possible explanation based on the findings presented in this paper is that xylan is sorbed at the surface of the lignin agglomerates: it increases the contact area between solid and liquid, thus making the particle structure more porous. The influence of ionic strength was also investigated through the addition of sodium sulphate: it was found that increasing the ionic strength of the slurries made the solids easier to separate, possibly due to a decrease in electrostatic repulsive interactions between the solids and the formation of a denser solid structure.

  • 3. Flyborg, L.
    et al.
    Björlenius, Berndt
    KTH, Skolan för bioteknologi (BIO), Industriell bioteknologi.
    Ullner, M.
    Persson, K. M.
    A PLS model for predicting rejection of trace organic compounds by nanofiltration using treated wastewater as feed2017Ingår i: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 174, s. 212-221Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this study a Partial Least Squares Projection of Latent Structures (PLS) model has been developed for predicting the rejection of pharmaceutical residuals by nanofiltration (NF) using treated municipal wastewater as feed. The objective was to provide a practical tool for wastewater reuse facilities for estimating the rejection of emerging organic contaminants based on their physiochemical characteristics. The model was developed by identifying the important physiochemical properties of pharmaceutical residuals for rejection by NF. The investigated pharmaceuticals were those present in the effluent from Henriksdal wastewater treatment plant (WWTP), Sweden. The rejection, at volume reduction factors (VRF) ranging from 2 to 20, was examined in a NF pilot plant at two occasions. The important variables for rejection by NF were, in descending order: polarizability, globularity, ratio hydrophobic to polar water accessible surface area and compound charge. Two studies were performed with a time interval of about a year with different wastewater matrices and age of membranes. For different VRFs, but in the same study, the model produced consistent predicted rejections. For the same VRF, but in the different studies, the regression lines were almost parallel, but with a deviation of about 7% for the predicted values. Most of the compounds were within the 95% prediction interval. The model also proved to be able to predict rejection using data from the literature. This confirms that the predictive PLS model can estimate the rejection albeit, with limitations. Generally the proposed predictive rejection model is most likely valid but the model coefficients need to be determined for each individual WWTP or wastewater reuse facility.

  • 4.
    Korkmaz, Kivanc
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Alemrajabi, Mahmood
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Rasmuson, Åke C.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik.
    Forsberg, Kerstin
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Kemiteknik, Resursåtervinning.
    Separation of Valuable Elements from NiMH Battery Leach Liquor via Antisolvent Precipitation2020Ingår i: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 234, artikel-id 115812Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Rare earth elements (REE) have been selectively recovered from NiMH battery leach liquors by antisolvent precipitation. The active anode material was leached using sulfuric acid. The REE were then separated from the other elements by precipitation as sulfates after addition of either ethanol or 2-propanol (antisolvent). In a second step, Ni and Co are separated as sulfates by the same technique. The concentration of elements in different acid alcohol mixtures at 25 degrees C and -10 degrees C respectively are presented as a function of time after addition of the alcohol, and the optimum conditions for separation of the REE in pure form are presented. Under optimum conditions, 5.6 mol/L (Organic/Aqueous (O/A) volumetric ratio = 0.7) of 2-propanol at 25 degrees C, 82% of the REE have precipitated 3 h after addition of the antisolvent and the purity is 99.9%.

  • 5.
    Kullab, Alaa
    et al.
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Martin, Andrew
    KTH, Skolan för industriell teknik och management (ITM), Energiteknik, Kraft- och värmeteknologi.
    Membrane distillation and applications for water purification in thermal cogeneration plants2011Ingår i: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 76, nr 3, s. 231-237Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Water treatment is an important auxiliary process in all thermal cogeneration plants. In this context membrane distillation (MD) is a novel technology that has potential advantages in: the ability to utilize low-grade heat instead of electricity; reduced sensitivity to fluctuations in pH or salt concentrations. This research is a continuation of a previously conducted theoretical study where the performance of MD-based water treatment was explored via laboratory testing, system simulations of thermodynamic performance, and economic evaluations. The current paper, encompassing field trials, contains details of a test rig deployed at Idbacken Cogeneration Facility (Nykoping, Sweden) with a five-module MD unit capable of producing 1-2 m(3)/day purified water. District heating supply line was employed for heating while municipal water was used for cooling; feed stocks include municipal water and flue gas condensate. A long-term performance evaluation including thorough chemical testing of product water quality is presented. (c) 2010 Elsevier B.V. All rights reserved.

  • 6.
    Marobhe, Nancy
    et al.
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik.
    Renman, Gunno
    KTH, Skolan för arkitektur och samhällsbyggnad (ABE), Mark- och vattenteknik.
    Jackson, Msafiri
    Mgana, Shabaan
    Purification of water from small man-made reservoirs by coagulation using purified proteins from Vigna and Parkinsonia seeds2008Ingår i: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794Artikel i tidskrift (Övrigt vetenskapligt)
  • 7.
    Mattsson, Tuve
    et al.
    KTH, Skolan för kemi, bioteknologi och hälsa (CBH), Centra, Wallenberg Wood Science Center. Chalmers Univ Technol, Dept Chem & Chem Engn, SE-41296 Gothenburg, Sweden.;Chalmers Univ Technol,.
    Lewis, William J. T.
    Univ Bath, Dept Chem Engn, Bath BA2 7AY, Avon, England..
    Chew, Y. M. John
    Univ Bath, Dept Chem Engn, Bath BA2 7AY, Avon, England..
    Bird, Michael R.
    Univ Bath, Dept Chem Engn, Bath BA2 7AY, Avon, England..
    The use of fluid dynamic gauging in investigating the thickness and cohesive strength of cake fouling layers formed during cross-flow microfiltration2018Ingår i: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 198, s. 25-30Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A common challenge during membrane filtration is cake fouling, whereby the build-up of material on the membrane surface reduces the permeate flux. Such fouling layers can also alter the selectivity of the separation. In this study, fluid dynamic gauging (FDG) is used in situ to investigate the cake fouling formed during cross-flow filtration of a model material: softwood Kraft lignin. FDG was used to estimate (i) the thickness of the cake layers (in the gm scale) and (ii) the local cohesive strength at different depths in the cake layer. Fouling layers formed at different transmembrane pressure (TMP) values were investigated. The estimated thickness of the cake layers increased with increasing TMP. However, it was difficult to capture the full cake thickness for the more loosely formed cakes layers. An increase in the cohesive strength of the cake was found to occur with increasing TMP values.

  • 8. Mattsson, Tuve
    et al.
    Sedin, Maria
    Theliander, Hans
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Filtration properties and skin formation of micro-crystalline cellulose2012Ingår i: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 96, s. 139-146Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Solid-liquid filtration is an important unit operation used in several applications in the pulp and paper industry. It can be challenging especially for materials that forms filter cakes that has a tendency to be highly compressible. The formation of a skin, i.e. an initial cake with a considerably higher filtration resistance, can further increase the filtration resistance for these filter cakes. The separation process in these cases requires considerably larger filter areas. This study investigates skin formation during the filtration of micro-crystalline cellulose, examining the effect of the filter medium, filtration pressure and pH. Depending on the choice of filter medium, the average specific filtration resistance was found to vary by more than one order of magnitude. A decrease in the suspension pH from 6.3 to 2.9 lowered both the filtration resistance and the differences between the filtration media. Using local pressure profiles, a region of high filtration resistance for some of the filter media and pH values was identified close to the bottom of the filter cell. Characterisation of the media and micro-crystalline cellulose indicated that internal clogging of the filter medium was unlikely. This suggests that the filter cake closest to the filter medium had a considerably higher filtration resistance compared to the cake formed immediately after, i.e. a skin had been formed under certain conditions.

  • 9.
    Mohamed, A.
    et al.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik. Cairo University, Egypt; Akhbar El Yom Academy, Egypt.
    Yousef, S.
    Ali Abdelnaby, M.
    Osman, T. A.
    Hamawandi, Bejan
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Toprak, Muhammet S.
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Muhammed, Mamoun
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik. Alexandria University, Egypt.
    Uheida, Abdusalam
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik.
    Photocatalytic degradation of organic dyes and enhanced mechanical properties of PAN/CNTs composite nanofibers2017Ingår i: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 182, s. 219-223Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This work describes the enhanced mechanical properties of the composite nanofibers and the photodegradation of two organic dyes using PAN/CNTs under UV irradiation at different volume concentration (0.05, 0.1, 0.2, and 0.3 wt.%). The composite nanofibers was performed with polyacrylonitrile (PAN), and carbon nanotubes (CNTs) by electrospinning process. The composite nanofibers structure and morphology is characterized by XRD, FTIR, SEM, and TEM. The result indicates that with increasing CNTs content, the mechanical properties of the composite nanofibers was enhanced, and became more elastic, and the elastic modulus increased drastically. The results of mechanical properties exhibit improvements in tensile strengths, and elastic modulus by 38% and 84% respectively, at only 0.05 wt.% CNTs. Moreover, photocatalytic degradation performance in short time and low power intensity was achieved comparison to earlier reports.

  • 10. Sathe, Priyanka
    et al.
    Myint, M. T. Z.
    Dobretsov, Sergey
    Dutta, Joydeep
    KTH, Skolan för informations- och kommunikationsteknik (ICT), Material- och nanofysik, Funktionella material, FNM.
    Removal and regrowth inhibition of microalgae using visible light photocatalysis with ZnO nanorods: a green technology2016Ingår i: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 162, s. 61-67Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Algal biofouling can be a major problem during membrane filtration processes reducing membrane efficiency. Removal of microalgae by visible light photocatalysis using zinc oxide (ZnO) nanorods was studied in this work. ZnO nanorods were grown on polypropylene support substrates. The treatment unit was constructed by incorporating ZnO nanocoated substrates in a glass tube. Anti-algal activity of the treatment units were tested using green microalga, Dunaliella salina, of 107 cells/mL concentration, which is higher than the concentration of cells during algal blooms. Nearly total algal cell inactivation was achieved within 2 h of continuous visible light illumination in the presence of nanocoated support substrates, as determined by flow cytometry analysis (98%) and trypan blue staining (95%). Uncoated support substrate under light illumination did not lead to algal cell mortality (1.7%). Complete inhibition of any regrowth of algal cells treated with nanocoated substrates was confirmed as no significant changes in the total number of cells were observed even after 2 weeks of incubation of the treated culture. The anti-algal activity of ZnO nanorods was attributed to the formation of reactive oxygen species (ROS) through photocatalytic processes. ZnO nanorod coated substrates used in the treatment units could be a suitable green method to control membrane fouling in water treatment plants avoiding the utilisation of harmful chemicals.

  • 11.
    Uheida, Abdusalam
    et al.
    KTH, Skolan för teknikvetenskap (SCI), Tillämpad fysik.
    Mohamed, Alaa
    Cairo Univ, EGNC, Egypt Nanotechnol Ctr, 6th October City 12588, Egypt.;Akhbar El Yom Acad, Prod Engn & Printing Technol Dept, Giza 12655, Egypt..
    Belaqziz, Majdouline
    Cadi Ayyad Univ, Natl Ctr Study & Res Water & Energy, BP 511, Marrakech 40000, Morocco..
    Nasser, Walaa S.
    Res Inst Med Entomol, Giza 12611, Egypt..
    Photocatalytic degradation of Ibuprofen, Naproxen, and Cetirizine using PAN-MWCNT nanofibers crosslinked TiO2-NH2 nanoparticles under visible light irradiation2019Ingår i: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 212, s. 110-118Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this work the photocatalytic degradation of pharmaceuticals (Ibuprofen, Cetirizine, and Naproxen) was evaluated using surface modified TiO2 nanoparticles immobilized on polyacrylonitrile/multiwall carbon nanotubes composite nanofibers. The photocatalytic degradation was studied under visible light (0.1 W/cm(2)) irradiation. Comparatively, the photocatalytic degradation of pharmaceuticals using PAN-CNT/TiO2-NH2 composite nanofibers was much more efficient than with PAN/TiO2-NH2 composite nanofibers under visible light irradiation. The results obtained showed that the photocatalytic efficiency of the studied pharmaceuticals is pH dependent in which more than 99% degradation was obtained at pH 2. Complete degradation of IBP, CTZ, and NPX was achieved within 200, 50, and 90 min, respectively under visible light.

  • 12.
    Wetterling, Jonas
    et al.
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Mattsson, Tuve
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Theliander, Hans
    KTH, Skolan för kemivetenskap (CHE), Centra, Wallenberg Wood Science Center.
    Effects of surface structure on the filtration properties of microcrystalline cellulose2014Ingår i: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 136, s. 1-9Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The filtration of biomaterials is often a challenge due to high filtration resistances and the formation of compressible filter cakes. This study investigates how the local filtration properties of microcrystalline cellulose, a biomaterial forming compressible filter cakes, are affected by the surface structure of its particles. The surface structure was modified through mechanical shearing and the treatment resulted in an increased surface ruggedness along with a small decrease in particle size distribution. The mechanical treatment was found to increase the local specific filtration resistance to a large extent whereas no significant change to the local filter cake solidosity was observed. The relationship between the local solidosity of the filter cake and the local specific filtration resistance could be described by a cell model as flow around porous spheres with negligible permeability. The effect of an increased surface ruggedness was represented in this model as an increased specific surface area subjected to drag as well as a decrease in particle solidosity.

  • 13. Wu, Yan
    et al.
    Fang, Mei
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Teknisk materialfysik.
    Lan, Lvdeng
    Zhang, Ping
    Rao, K. Venkat
    KTH, Skolan för industriell teknik och management (ITM), Materialvetenskap, Teknisk materialfysik.
    Bao, Zhengyu
    Rapid and direct magnetization of goethite ore roasted by biomass fuel2012Ingår i: Separation and Purification Technology, ISSN 1383-5866, E-ISSN 1873-3794, Vol. 94, s. 34-38Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biomass is a renewable and carbon neutral solid fuel. Utilization of biomass in iron ore roasting process as heating agent and reducing agent contributes to energy conservation and emission reduction, and can partially replace for coal and coke. The biomass instead of coke was mixed together with iron ore powder from the north of Hainan province into ball roasting process to investigate the effects of mixture composition, reduction temperature, reaction time, the thermal reduction and magnetic properties of the mixture. The results show that the reduction temperature, reaction time and dosage of the biomass are correlated to the quality of the reduction and the magnetism of the iron ore, within the experimental conditions. The mechanism of the biomass reducing the weakly magnetic goethite into stronger magnetic iron oxide has been discussed. The results show that the goethite ores is dramatically reduced and magnetized by about 20 wt.% biomass at low roasting temperature. Application of biomass energy in iron ores roasting process is prospective to the effective use of biomass and for decreasing the consumption of fossil fuels in the steelmaking process.

1 - 13 av 13
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