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Plasticization effect on performance of polyphenylene oxide hollow fiber membrane at high concentrations of hydrogen sulfide
, Article 19th International Congress of Chemical and Process Engineering, CHISA 2010 and 7th European Congress of Chemical Engineering, ECCE-7, 28 August 2010 through 1 September 2010 ; 2010 ; Niknejad, S. M. S ; Soltanieh, M ; Sharif University of Technology
Abstract
Natural gas contains several impurities, e.g., CO 2 and H 2S, which have undesirable effects on the performance of the glassy polymeric membranes. The plasticization effect of H 2S at high concentrations on the gas separation performance of polyphenylene oxide hollow fiber membrane has been studied at different compositions of H 2S and feed pressures. The existence of high concentrations of H 2S in CH 4 feed mixture, which is present in many natural gas sources in Iran, enhances plasticization. For a H 2S/CH 4 mixture containing 5008 ppm H 2S at ≈ 75 psig, the H 2S permeance reduces by > 45% from its initial value. H 2S acts as a plasticizer in H 2S/CH 4 membrane separation at elevated...
The effect of ethane on the performance of commercial polyphenylene oxide and cardo-type polyimide hollow fiber membranes in CO 2/CH 4 separation applications
, Article Korean Journal of Chemical Engineering ; Volume 27, Issue 6 , 2010 , Pages 1876-1881 ; 02561115 (ISSN) ; Savoji, H ; Soltanieh, M ; Matsuura, T ; Tabe, S ; Sharif University of Technology
2010
Abstract
Impurities such as hydrogen sulfide, water vapor and heavy hydrocarbons in natural gas have considerable effects on the membrane performance. Small amounts of condensable and polymer soluble components in the feed gas cause swelling or plasticization of glassy membranes, leading to a reduction in membrane selectivity. In the present research the influence of ethane was investigated on the permeance and selectivity of two commercially available hollow fiber membranes, namely Cardo-type polyimide and PPO hollow fibers for CO 2/CH 4 separations. It was concluded that the gas mixture permeation rate was increased in the presence of C 2H 6. However, the CO 2/CH 4 separation factors remained...
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) ; Savoji, H ; Soltanieh, M ; Matsuura, T ; Tabe, S ; Sharif University of Technology
Abstract
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...
Mathematical modeling and simulation of hollow fiber membranes for separation of gas mixtures: Case study with separation of H 2S/CH 4 by polyphenylene oxide (PPO) hollow fiber module
, Article 19th International Congress of Chemical and Process Engineering, CHISA 2010 and 7th European Congress of Chemical Engineering, ECCE-7, Prague, 28 August 2010 through 1 September 2010 ; 2010 ; Savoji, H ; Soltanieh, M ; Sharif University of Technology
2010
Abstract
A mathematical model has been developed that is based the dual sorption in the dense layer and pore flow in the porous layer. In the porous layer a resistance model is applied where four mechanisms, i.e., Knudsen, Viscous, Slip, and Surface flows, are superimposed. Steady-state, constant pressure along the membrane and constant physical properties are assumed. Its application to the separation of H 2S/CH 4 gas mixtures as a sour gas in natural gas sweetening by using a PPO hollow fiber module is put forward. The Quasi Newton method is used to determine the parameters of membrane transport model for the case of H 2S/CH 4 separation. The H 2S and CH 4 permeances increased by increasing the...
Electrospun nanofibers
, Article Solid-Phase Extraction ; 2019 , Pages 311-339 ; 9780128169063 (ISBN) ; Rezvani, O ; Zeinali, S ; Asgari, S ; Golzari Aqda, T ; Manshaei, F ; Sharif University of Technology
Elsevier
2019
Abstract
Electrostatic fiber fabrication technique has evinced more interest and attention in recent years, owing to its versatility, reliability, and potential for applications in diverse fields, particularly separation, extraction, and filtration. The sub-micro fibers are generated by employing strong electric field on polymeric solutions or melt is led to the soft nanometric mats. So far, more than 100 polymers have been Electrospun and this number is gradually increasing. Over recent decades, a remarkable variety of electrospun nanofibers as promising and authentic extracting platforms have been synthesized. They offer various advantages including high surface area-to-volume ratio and tunable...
Electrospun nanofibers
, Article Solid-Phase Extraction ; 2019 , Pages 311-339 ; 9780128169063 (ISBN) ; Rezvani, O ; Zeinali, S ; Asgari, S ; Aqda, T. G ; Manshaei, F ; Sharif University of Technology
Elsevier
2019
Abstract
Electrostatic fiber fabrication technique has evinced more interest and attention in recent years, owing to its versatility, reliability, and potential for applications in diverse fields, particularly separation, extraction, and filtration. The sub-micro fibers are generated by employing strong electric field on polymeric solutions or melt is led to the soft nanometric mats. So far, more than 100 polymers have been Electrospun and this number is gradually increasing. Over recent decades, a remarkable variety of electrospun nanofibers as promising and authentic extracting platforms have been synthesized. They offer various advantages including high surface area-to-volume ratio and tunable...
Comprehensive modeling and CFD simulation of absorption of CO2 and H2S by MEA solution in hollow fiber membrane reactors
, Article AIChE Journal ; Vol. 60, issue. 2 , 2014 , pp. 657-672 ; ISSN: 00011541 ; Memardoost, S ; Dehkordi, A. M ; Sharif University of Technology
Abstract
A comprehensive mathematical model has been developed for the simulation of simultaneous chemical absorption of carbon dioxide and hydrogen sulfide by means of Monoethanolamine (MEA) aqueous solution in hollow fiber membrane reactors is described. In this regard, a perfect model considering the entrance regions of momentum, energy, and mass transfers was developed. Computational Fluid Dynamics (CFD) techniques were applied to solve governing equations, and the model predictions were validated against experimental data reported in the literature and excellent agreement was found. Effects of different disturbances on the dynamic behavior of the reactor were investigated. Moreover, effects of...
Preparation of Hemodialysis Membrane on the Basis of Polysulfone
, M.Sc. Thesis Sharif University of Technology ; Moosavi, Ali (Supervisor) ; Abd Khodaei, Mohammad Jafar (Supervisor)
Abstract
In Hemodialysis, membrane dialyser and commonly hollow fibers are used to treat patients who suffer from end stage renal failure. When blood flows into membrane, it loses uremic toxins such as urea and creatinine. On the other hand, some of the vital proteins of blood pass through the membrane or they are adsorbed on the membrane surface. The more hydrophilicity of the membrane, the less adsorption of proteins is. In this study, to achieve high hydrophilicity and low adsorption of proteins on the polysulfone membrane surface, the presence of hydrophilic nano-particles SBA-15 in membrane composition is investigated. The nano-particles with mass percentages 0.25%, 0.5 % and 1 % to one mass of...
Simultaneous separation of H2S and CO2 from natural gas by hollow fiber membrane contactor using mixture of alkanolamines
, Article Journal of Membrane Science ; Volume 377, Issue 1-2 , July , 2011 , Pages 191-197 ; 03767388 (ISSN) ; Soltanieh, M ; Mousavi, S. A ; Sharif University of Technology
2011
Abstract
In the present work we studied the use of a membrane contactor system for simultaneous absorption of H2S and CO2 from a gas mixture similar to natural gas. MDEA solution and mixtures of MDEA/DEA and MDEA/MEA were used as absorbent liquid. PVDF and PSf hollow fiber membranes were used in the membrane contactor modules. Design of experiments were carried out by Taguchi method in a manner that a systematical investigation of the effect of operational parameters (temperature, pressure, gas and liquid flow rates, absorbent concentration and acid gas content of the feed), in addition to the effect of membrane material and absorbent liquid, was implemented on process performance parameters...
Hydrogen separation from gas mixtures using polymeric membranes
, M.Sc. Thesis Sharif University of Technology ; Mousavi, Abbas (Supervisor) ; Bastani, Darioush (Supervisor) ; Sadatnia, Behrooz (Co-Advisor)
Abstract
Because of higher hydrogen demand in recent years, study of hydrogen separation from gas mixtures is highly regarded. Because of some parameters such as high surface to volume ratio and ability to withstanding high pressure, polymeric hollow fiber membranes have a good potential of hydrogen recovery. So in this study, fabrication of single-layer and dual-layer hollow fiber membranes have been investigated. Selective polymer that used in both single and dual layer membranes is polyethersulfone. Membranes were fabricated by dry-wet phase inversion method and effects of extrusion rates and their ratio, composition and temperature of polymer solution, composition of bore fluid, coating and air...
Modeling and Simulation of Hollow Fiber Membrane Contactor in Presence of Nanoparticles
, M.Sc. Thesis Sharif University of Technology ; Molaei Dehkordi, Asghar (Supervisor) ; Safekordi, Ali Akbar (Supervisor)
Abstract
In this study, a comprehensive 2D mathematical model has been developed for the simulation of physical and chemical absorption of carbon dioxide in hollow fiber membrane contactors in the presence of nanoparticles. The model were developed by considering molecular diffusion in radial and axial directions as well as non-wetting conditions. Carbon dioxide absorption was simulated from a gas mixture containing carbon dioxide and air, that flows in the shell. Also, absorbent containing nanoparticles flows in tube side and counter currently. Effects of presence of nanoparticles were modeled by taking into account two prominent mechanisms proposed in the literature for mass transfer enhancement in...
Evaluation of Hollowfiber Membranes Uesd In Hemodialysis
, M.Sc. Thesis Sharif University of Technology ; Abdekhodaei, Mohammad Jafar (Supervisor)
Abstract
Due to largre number of patients treated by dialysis and its significant increasing progress, dialysis efficiency and patients' life quality are of great interest.Dialyzer, the dialysis beating heart, has the role of cleaning blood by removing toxic solutes and balancing volume of bood's water through hollow fiber membranes. In this thesis, firstly we tried to focus on performance characteristics of dialyzer by studying effective parameters influencing dialyzer efficiency and ultimately we set two important performance characteristics, ultrafiltration coefficient and solute clearance, as our goal parameters for evaluating dialyzer's yield. To this purpose, we designed an experimental set...
Gas permeation properties of commercial polyphenylene oxide and Cardo-type polyimide hollow fiber membranes
, Article Separation and Purification Technology ; Volume 51, Issue 3 , 2006 , Pages 359-366 ; 13835866 (ISSN) ; Soltanieh, M ; Matsuura, T ; Tabe Mohammadi, A ; Feng, C ; Sharif University of Technology
2006
Abstract
Gas separation properties of commercially available polyphenylene oxide (PPO) and Cardo-type polyimide (PI) hollow fiber membranes were investigated by CO2/CH4 and O2/N2 separation experiments. The pure gas permeation and the mixed gas separation experiments indicated that the two hollow fiber membranes were suitable candidates for O2/N2 and CO2/CH4 separations. Average O2/N2 permselectivities of 3.9 and 5.7 for PPO and PI hollow fibers, respectively, average CO2/CH4 permselectivities of 16.4 and 36.0 for PPO and PI hollow fibers, respectively, CO2 permeances of 210 and 110 GPU at 100 psig for PPO and PI hollow fibers, and O2 permeances of 40 GPU and 15 GPU for PPO and PI hollow fibers were...
Electrospun superhydrophobic polystyrene hollow fiber as a probe for liquid–liquid microextraction with gas chromatography-mass spectrometry
, Article Journal of Separation Science ; Volume 39, Issue 19 , 2016 , Pages 3782-3788 ; 16159306 (ISSN) ; Baktash, M. Y ; Jahandar, K ; Sharif University of Technology
Wiley-VCH Verlag
2016
Abstract
A superhydrophobic polystyrene hollow fiber was electrospun around a copper spring collector. This approach led to the construction of a hollow fiber membrane, and the copper spring acted as a scaffold. The characteristic properties of the hollow fiber were studied by scanning electron microscopy. The membrane was used as a probe to transfer the extracting solvent from aquatic media to a gas chromatograph. After performing the liquid–liquid microextraction procedure on 10 mL of water sample by octanol, the whole solution was passed through the prepared polystyrene hollow fiber. Propanol, containing 2 mg/L lindane as the internal standard, was used for desorption and an aliquot of 2 μL of the...
Gas absorption enhancement in hollow fiber membrane contactors using nanofluids: Modeling and simulation
, Article Chemical Engineering and Processing: Process Intensification ; Volume 119 , 2017 , Pages 7-15 ; 02552701 (ISSN) ; Rahimi, M ; Molaei Dehkordi, A ; Sharif University of Technology
Elsevier B.V
2017
Abstract
In this article, a comprehensive 2D mathematical model has been developed to simulate process intensification of carbon dioxide absorption in the presence of nanoparticles in hollow fiber membrane contactors (HFMCs). The influences of nanoparticle were taken into account considering Brownian motion and Grazing effect as dominant phenomena of mass-transfer enhancement in nanofluids. The obtained simulation results were validated against experimental data reported in the literature and excellent agreement was obtained. It was found that by adding 0.05 wt % silica nanoparticles, the absorption rate could be enhanced by 16%, while the corresponding value is 32% for CNT nanoparticles. High...
MBBR and MBR Reactor Configuration for Better Performance
, M.Sc. Thesis Sharif University of Technology ; Borgheei, Mahdi (Supervisor)
Abstract
Membrane bioreactors (MBRs) which are commonly understood as the combination of membrane filtration and biological treatment using activated sludge have several advantages, but membrane fouling reduces the membrane efficiency, permeability and lifetime. An alternative is replacing a moving bed biofilm reactor (MBBR) with the activated sludge system which may reduce the effect of membrane fouling. The sludge produced in MBBRs has poor settling characteristics, therefore, their efficiency is limited by the sedimentation tank performance and they require a larger settling surface. The combination of moving bed biofilm reactors and membrane bioreactors can compensate for the drawbacks of both of...
Membrane Bioreactor for the Treatment of Dairy Industry Wastewater
, M.Sc. Thesis Sharif University of Technology ; Alemzadeh, Iran (Supervisor) ; Vossoughi, Manoochehr (Supervisor)
Abstract
The dairy industry wastewater has high biological oxygen demand(BOD) and high chemical oxygen demand(COD). In this study, membrane bioreactor(MBR) was used for the treatment dairy industry wastewater. Since two diffuser,submerged membrane modul and intermittent suction method were adpted to system. In this study, the response surface method and experimental design were applied as an alternative to conventional methods for the optimization of the treatment. A central composite design, with 5 replicates at the center point were used to build a model for predicting and optimizing the treatment. Mathematical model equations were derived by computer simulation programming with Design Expert...
Ground Water Denitrification by Packed Bed Bioreactor With KMT Packing
, M.Sc. Thesis Sharif University of Technology ; Borghei, Mehdi (Supervisor)
Abstract
In this study biological denitrification method by moving bed biofilm reactor is investigated. The main advantage of MBBR reactor is due to their capacity for high removal rates and low operational problems such as clogging. Two MBBRs in series with 3 liter volume each, were designed in experimental set up and used in this research. Nitrification reactor worked under aerobic conditions and denitrification reactor operated under anaerobic conditions. Methanol was used as carbon source in the reactors throughout the study. Fifty percent of each reactor volume was occupied with KMT1 packing. To finding the optimum nitrate loading rate, the concentration of ammonium and nitrate were changed from...
Fabrication and Modification of Hollow Fiber Polysulfone Membrane Using Uio-66-NH2 and Mil-125-NH2 Nanoparticles by Mixed Matrix Method
, M.Sc. Thesis Sharif University of Technology ; Mousavi, Abbas (Supervisor) ; Bastani, Daruish (Supervisor)
Abstract
This study aims to investigate polysulfone (PSF) hollow fiber mixed matrix membranes (MMMs) properties containing Uio-66-NH2 and Mil-125-NH2 nanoparticles, groups of metal-organic frameworks (MOFs), for hemodialysis application. The nanoparticles were synthesized, and the membranes were produced by the phase inversion method. Membranes characterization conducted by ATR-FTIR, FE-SEM, EDX, TEM, and AFM was confirmed the presence of MOFs nanoparticles. Also, the evaluation of specific surface area of nanoparticles was done by BET. The water contact angle (WCA) results indicated the improvement of MMMs hydrophilicity, enhancing the pure water flux from 46.8 L/ m2h for the pristine membrane to...
Application of Cardo-type polyimide (PI) and polyphenylene oxide (PPO) hollow fiber membranes in two-stage membrane systems for CO2/CH4 separation
, Article Journal of Membrane Science ; Volume 324, Issue 1-2 , 2008 , Pages 85-94 ; 03767388 (ISSN) ; Soltanieh, M ; Matsuura, T ; Tabe Mohammadi, A ; Sadeghi, M ; Sharif University of Technology
Elsevier B.V
2008
Abstract
In this study, a two-stage membrane system for the separation of CH4/CO2 was designed based on a series of laboratory-scale experiments obtained using two types of commercial hollow fiber membranes including polyphenylene oxide (PPO) and Cardo-type polyimide (PI). The former showed high permeability and low to moderate selectivity, while the latter exhibited high selectivity and moderate permeability. In this design, the permeate from the first stage - rich in CO2 but containing considerable amount of methane - is fed into the second stage to recover its methane content. The performances of double- and single-stage system designs were compared in terms of methane loss (the ratio of methane...