Search for: membranes
0.038 seconds
Total 718 records

    Preparation and performance evaluation of a Nano-composite silica membrane for high temperature gas separation

    , Article CHISA 2012 - 20th International Congress of Chemical and Process Engineering and PRES 2012 - 15th Conference PRES ; 2012 Safekordi, A ; Amanipour, M ; Heidari, M ; Ganji Babakhani, E ; Ordookhani, G ; Sharif University of Technology
    Multi-layer ceramic membranes were prepared and used for hydrogen separation at high operating temperatures. The membranes were formed by depositing nano-scale, dense silica layers with a thickness of 80-90 nm on top of porous alumina substrates by atmospheric CVD method. The substrates were prepared by dipping macroporous α-alumina supports with three size-controlled boehmite solutions to obtain a graded structure. Permeation tests were performed at 800°C for single gases of H2, N2, CH4, and CO2. Hydrogen selectivity values of 100, 350, and 780 were obtained as the ratio of H2 permeation flux over CH4, N2, and CO2, respectively. This is an abstract of a paper presented at the CHISA 2012 -... 

    Preparation of mesh-reinforced cellulose acetate forward osmosis membrane with very low surface roughness

    , Article Korean Journal of Chemical Engineering ; Volume 34, Issue 12 , 2017 , Pages 3170-3177 ; 02561115 (ISSN) Mirkhalili, S. M ; Mousavi, S. A ; Ramazani Saadat Abadi, A ; Sadeghi, M ; Sharif University of Technology
    Mesh-reinforced cellulose acetate (CA)-based membranes were prepared for forward osmosis (FO) by immersion precipitation. Casting compositions such as CA percent and 1, 4-dioxane/acetone ratio and also preparation conditions such as evaporation time, coagulation bath and annealing temperatures were tested for membranes’ performance. The results were compared with commercially CTA membranes. The best membrane (17.9% polymer and 1, 4-dioxane/acetone ratio of 1.89) showed water flux of 9.3 L/m2h (LMH) and RSF of 0.536 mol NaCl/m2h. Moreover, the membrane structure was reinforced by a polyester mesh, which created micro pores in the back of the membrane. This caused higher water flux and RSF... 

    Preparation and characterization of polycarbonate/thermoplastic polyurethane blend membranes for wastewater filtration

    , Article Journal of Water Process Engineering ; Volume 16 , 2017 , Pages 170-182 ; 22147144 (ISSN) Nazemidashtarjandi, S ; Mousavi, S. A ; Bastani, D ; Sharif University of Technology
    Elsevier Ltd  2017
    The polycarbonate (PC)/thermoplastic polyurethane (TPU) blend membranes were prepared by phase inversion process applied to membrane bioreactor (MBR) to investigate the fouling characteristics. The impact of TPU and poly (vinylpyrrolidone) PVP concentration in polymer dopes on membrane structure, morphology, and performance were studied. The flat sheet fabricated membranes were characterized by scanning electron microscope (SEM), water contact angle (WCA), membrane surface roughness measurements and mechanical strength. The membrane performance was investigated at subcritical operating conditions. Pure water and critical flux through the fabricated membranes were measured for better... 

    Practical techniques for improving the performance of polymeric membranes and processes for protein separation and purification

    , Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 37, Issue 2 , February , 2018 , Pages 1-23 ; 10219986 (ISSN) Vedadghavami, A ; Minooei, F ; Hosseini, S. S ; Sharif University of Technology
    Iranian Journal of Chemistry and Chemical Engineering  2018
    Protein separation and purification technologies play an essential role in various industries including but not limited to pharmaceuticals, dairy as well as the food sector. Accordingly, a wide variety of techniques such as chromatography and electrophoresis have been developed and utilized extensively over the years for this purpose. Despite their widespread acceptance, conventional techniques still suffer from major limitations and complexities such as short lifetime, low productivity, high-pressure drop and difficulty in scale-up among others. Membrane separation processes have received significant attention in recent years as a promising alternative that can potentially overcome the... 

    Structural and transport properties of polydimethylsiloxane based polyurethane/silica particles mixed matrix membranes for gas separation

    , Article Korean Journal of Chemical Engineering ; Volume 31, Issue 5 , 2014 , Pages 841-848 ; ISSN: 02561115 Semsarzadeh, M. A ; Ghalei, B ; Fardi, M ; Esmaeeli, M ; Vakili, E ; Sharif University of Technology
    Mixed matrix membranes of synthesized polyurethane (PU) based on toluene diisocyanate (TDI), polydimethylsiloxane (PDMS) and polytetramethylene glycol (PTMG) with polyvinyl alcohol based polar silica particles were prepared by solution casting technique. The homogeneity and thermal properties of the prepared PDMS-PU/silica membranes were characterized using scanning electron microscope (SEM), differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA). The SEM micrographs confirmed the distribution of silica particles in the polymer matrix without agglomerations. Gas permeation properties of membranes with different silica contents were studied for pure CO2, CH4, O2, He... 

    Statistical assessment of starch removal from starchy wastewater using membrane technology

    , Article Korean Journal of Chemical Engineering ; Volume 28, Issue 9 , 2011 , Pages 1889-1896 ; 02561115 (ISSN) Sargolzaei, J ; Moghaddam, A. H ; Shayegan, J ; Sharif University of Technology
    The present work deals with application of 25-2 fractional factorial design (FFD) to evaluate the operating parameters on starch separation from synthetic starchy wastewater using a hydrophilic polyethersulfone membrane with 0.65 μm pore size in a plate and frame handmade membrane module. The analysis of variance (ANOVA) combined with F-test was also used to recognize non-significant terms. The performance of the filtration process was evaluated by calculating the COD removal percentage (rejection factor) and permeate flux. In this experiment, five input parameters were surveyed, including trans membrane pressure (TMP), flow and temperature of feed, pH and concentration of wastewater. In... 

    Response to comment on 'CFD modeling of CO2 absorption in membrane contactors using aqueous solutions of monoethanolamine-ionic liquids

    , Article Industrial and Engineering Chemistry Research ; Volume 60, Issue 3 , 2021 , Pages 1503-1504 ; 08885885 (ISSN) Pahlavanzadeh, H ; Darabi, M ; Ghaleh, V. R ; Bakhtiari, O ; Sharif University of Technology
    American Chemical Society  2021

    Optimization of Membrane Structure in Membrane Bio-Reactor Application

    , M.Sc. Thesis Sharif University of Technology Khosravizade, Rouhollah (Author) ; Mousavi, Abbas (Supervisor) ; Bastani, Daruosh (Co-Advisor)
    Reusing valuable materials such as water is one of the ways to achieve sustainable development. Membrane bioreactor technology (MBR) is one of the ways to reuse water and this is an alternative to another way to upgrade existing refinery.Structure and porosity of the membranes used in MBR Systems, porosity distribution, Hydrophilic or hydrophobicity of the membrane and surface roughness are very important Parameters that impact the ultimate performance of membrane bioreactor. Hence, this project focuses on optimization membrane structure to purification a specific type of wastewater. So amount of polymer and nanoparticle membrane for MBR systems should determined by experiment design.In this... 

    , M.Sc. Thesis Sharif University of Technology Bakhtiari, Fatemeh (Author) ; Mosavi, Abbas (Supervisor) ; Shojaei, Akbar (Co-Advisor)
    In this work nanocomposite CNT/polysulfone and CNT/polyethersulfone membranes for membrane contactor application in gas separation were fabricated. The two types of CNTs used for chemical and physical separation of H2S from a mixture of CH4 an H2S, had the outer diameter of 20-30nm and 50-100nm. One of the greatest concerns about using membrane contactors for gas separation applications is the wetting of membranes which consequently leads to decrease in separation performance. The aim of this study is to enhance the hydrophobicity of membranes by mixing hydrophobic carbon nanotubes in the polymeric matrix. The effect of factors like type of the polymer, diameter of the carbon nanotube and... 

    Influence of crossflow microfiltration on ceramic membrane fouling and beer quality

    , Article Desalination and Water Treatment ; Volume 51, Issue 22-24 , 2013 , Pages 4302-4312 ; 19443994 (ISSN) Kazemi, M. A ; Soltanieh, M ; Yazdanshenas, M ; Fillaudeau, L ; Sharif University of Technology
    Taylor and Francis Inc  2013
    In this article, an experimental investigation has been carried out to determine the types of fouling phenomena that occur during clarification of dilute malt extract (DME) and pasteurization of clarified beer (CB) by a tubular ceramic membrane in a crossflow pilot plant. Using the classical models, the predominant fouling mechanism responsible for flux decline was found to be complete blocking of the membrane pores followed by formation of a compressible cake layer of yeast cell in the case of DME clarification, whereas the internal fouling of the membrane occurs during pasteurization of CB. The effects of operating parameters, including temperature, transmembrane pressure, and crossflow... 

    Preparation and characterization of poly (vinyl chloride) (PVC) based membrane for wastewater treatment

    , Article Journal of Water Process Engineering ; Volume 16 , 2017 , Pages 98-107 ; 22147144 (ISSN) Ghazanfari, D ; Bastani, D ; Mousavi, S. A ; Sharif University of Technology
    Elsevier Ltd  2017
    This study concentrates on fabrication of low-cost antifouling membranes by incorporation of alumina in PVC membranes for membrane bioreactor (MBR). PVC based membranes were prepared via phase inversion method at different alumina contents. Pure water flux through the membranes and its antifouling properties in MBR setup at operating pressure of −0.4 bar were studied. The effects of the alumina on the morphology and physical properties of the membranes were investigated by scanning electron microscopy (SEM), atomic force microscopy (AFM), contact angle, pore size, viscosity, porosity, and mechanical properties. The results showed that the membrane with 3 wt% alumina exhibited excellent... 

    Transport of small polar molecules across nonporous polymeric membranes: II. Shortcomings of phenomenological models of membrane transport

    , Article Journal of Membrane Science ; Volume 211, Issue 2 , 2003 , Pages 215-234 ; 03767388 (ISSN) Ghoreyshi, A. A ; Farhadpour, F. A ; Soltanieh, M ; Abdelghani, M ; Sharif University of Technology
    A molecule within the nonporous polymeric membrane moves in response to the local driving force and has no memory of how it entered the membrane or how the local gradients were generated. This means that a properly formulated model of transport within the membrane should be equally applicable to dialysis, pervaporation or vapour permeation. The phenomenological approach of irreversible thermodynamics was used to develop transient models of dialysis and pervaporation. The model developed in this study were validated against transient dialysis and pervaporation data for ethanol-water/silicone rubber system. A critical assessment was obtained by recovering the model parameters from the dialysis... 

    Interaction effects in multicomponent separation by reverse osmosis

    , Article Journal of Membrane Science ; Volume 183, Issue 1 , 2001 , Pages 15-27 ; 03767388 (ISSN) Soltanieh, M ; Sahebdelfar, S ; Sharif University of Technology
    Elsevier  2001
    Separation of multicomponent mixtures, in particular ternary systems, was investigated theoretically and experimentally. The interactions in various multicomponent mixtures were determined. Using data from literature as well as the limited data obtained in our laboratory, we identified the situations where the multicomponent effects are strong. A correlation between the coupled permeability coefficients and straight permeability coefficients and concentration of components in ternary systems was obtained. Capabilities of thermodynamic models in describing the electrolyte-nonelectrolyte systems consisting of a weak acid were also investigated. The results of this work show that the... 

    Preparation and Characterization of Electrospun Nanofiberous Membranes for Wastewater Treatment

    , M.Sc. Thesis Sharif University of Technology Seyed Shahabadi, Mahdi (Author) ; Bastani, Daruoosh (Supervisor) ; Moosavi, Ali (Supervisor)
    The aim of the current project is preparation, characterization and microfiltration evaluation of nanofiberous membrane. In order to prepare membranes, the electrospinning method was utilized and polyacrylonitrile and N-N, dimethylformamide (DMF) were used as the polymer and the solvent, respectively. As the nanofiber diameter controls the structure of the membrane and also bead formation reduces the membrane uniformity, at first the effects of four most influential electrospinning parameters, such as solution concentration, applied voltage, floe rate, and the distance between needle tip and the collector, on average fiber diameter and bead area density were investigated via response surface... 

    Optimization of conditions in ultrafiltration treatment of produced water by polymeric membrane using Taguchi approach

    , Article Desalination and Water Treatment ; Volume 51, Issue 40-42 , 2013 , Pages 7499-7508 ; 19443994 (ISSN) Reyhani, A ; Rekabdar, F ; Hemmati, M ; SafeKordi, A. A ; Ahmadi, M ; Sharif University of Technology
    Desalination Publications  2013
    In this study, the ultrafiltration of produced water was studied using a two-stage ultrafiltration process. In the first stage, the influences of operating parameters, including transmembrane pressure, temperature, and cross-flow velocity on the amount of flux decline caused by membrane fouling, were investigated using a polymeric membrane. In order to design the experiments and optimize the experimental results, the Taguchi method was applied. L9 (33) orthogonal array for experimental planning and the smaller-the-better response category was selected to obtain optimum conditions because the lowest flux decline was our aim. Analysis of variance was used to determine the most important... 

    Desalination through sweeping gas membrane distillation alternative

    , Article CHISA 2012 - 20th International Congress of Chemical and Process Engineering and PRES 2012 - 15th Conference PRES ; 2012 Bastani, D ; Kargari, A ; Shirazi, M. M. A ; Fatehi, L ; Soleimani, M ; Sharif University of Technology
    Sweeping gas membrane distillation process was studied using flat sheet hydrophobic PTFE membrane. The effects of operating parameters, including feed temperature, feed flow rate, sweeping gas flow rate, and feed concentration on the permeate flux, were determined. The feed temperature significantly influenced the permeate flux. Increasing the feed temperature increased the permeate flux. The increase of feed concentration caused to reduce the permeate flux due to the increase of concentration polarization effect and reduction of vapor pressure difference. Sweeping gas flow rate led to increase the permeate flux due to reduction of vapor pressure in the permeate side. Higher air flow rate... 

    Preparation and characterization of PES and PSU membrane humidifiers

    , Article Journal of Membrane Science ; Volume 383, Issue 1-2 , 2011 , Pages 197-205 ; 03767388 (ISSN) Samimi, A ; Mousavi, S. A ; Moallemzadeh, A ; Roostaazad, R ; Hesampour, M ; Pihlajamaki, A ; Manttari, M ; Sharif University of Technology
    Polysulfone (PSU) and polyethersulfone (PES) porous membranes; and mixed polymer with nanoparticles TiO2, were prepared for air humidification. The mechanical properties and morphology of these membranes were studied by Tensile tester and SEM/EDX. The effects of membrane composition and operating factors on humidifier performance were investigated. The results revealed that the membrane composition and its structure have significant effect on humidification. The porous membranes with finger type cavities had higher humidification performance but lower mechanical properties. Water flux of the membranes was about 0.16-0.2L/hm2 at 25°C. Furthermore, adding 0.1wt% TiO2 nanoparticles to casting... 

    Removal of hydrogen sulfide from methane using commercial polyphenylene oxide and Cardo-type polyimide hollow fiber membranes

    , Article Korean Journal of Chemical Engineering ; Volume 28, Issue 3 , March , 2011 , Pages 902-913 ; 02561115 (ISSN) Chenar, M. P ; Savoji, H ; Soltanieh, M ; Matsuura, T ; Tabe, S ; Sharif University of Technology
    The performance of commercially available poly (2,6-dimethyl-1,4-phenylene oxide) (PPO) and Cardotype polyimide (PI) hollow fiber membranes was investigated in removing hydrogen sulfide from methane in a series of bench-scale experiments. It was observed that in the concentration range of hydrogen sulfide in methane from 101 to 401 ppm, the methane permeability decreased in the presence of hydrogen sulfide for Cardo-type polyimide hollow fiber membranes, whereas the PPO membrane performance was not affected. The separation coefficients of hydrogen sulfide/methane were 6 and 4 for PI and PPO membranes, respectively. Effects of temperature on the performance of PI and PPO membranes were... 

    Vacuum enhanced membrane distillation for trace contaminant removal of heavy metals from water by electrospun PVDF/TiO2 hybrid membranes

    , Article Korean Journal of Chemical Engineering ; Volume 33, Issue 7 , 2016 , Pages 2160-2168 ; 02561115 (ISSN) Moradi, R ; Monfared, S. M ; Amini, Y ; Dastbaz, A ; Sharif University of Technology
    Springer New York LLC 
    Electrospun hybrid membranes were synthesized using electrospinning of Poly (vinylidenefluoride) - titanium tetraisopropoxide (PVDF-TTIP) sol. Asymmetric post-treatment of membrane conducted for deprotonation of titanate and making hydrophilic/hydrophobic dual characteristics. The membranes were characterized by various methods such as wettability, scanning electron microscopy, infrared spectroscopy, X-ray diffraction and liquid entry pressure tests. For evaluating the separation performance, these membranes were applied in the VMD process to treat water heavy metal contaminants. The effects of operating parameters such as flow rate, temperature and membrane properties as porosity, on... 

    Preparation and characterization of PVC/PAN blend ultrafiltration membranes: Effect of PAN concentration and PEG with different molecular weight

    , Article Desalination and Water Treatment ; Volume 58 , 2017 , Pages 1-11 ; 19443994 (ISSN) Rabiee, H ; Mojtaba Seyedi, S ; Rabiei, H ; Alvandifar, N ; Arya, A ; Sharif University of Technology
    Desalination Publications  2017
    The current study investigates the effect of polyacrylonitrile (PAN) addition on morphology and antifouling properties of poly(vinyl chloride) (PVC) asymmetric flat ultrafiltration (UF) membranes. The membranes are prepared via phase inversion method induced by immersion precipitation at different PVC/PAN blending ratio up to 40 wt% PAN. Also, membranes with blending ratio of PVC/ PAN:70/30, which showed the highest water flux and flux recovery ratio, were used for membrane preparation with 4 wt% of Polyethylene glycol (PEG) addition in four different molecular weight, 600 Da, 1,000 Da, 6,000 Da and 20,000 Da, which was used as pore former and hydrophilic polymeric additive. The performance...