The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Robert Y M Huang - One of the best experts on this subject based on the ideXlab platform.
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chitosan anionic surfactant complex membranes for the Pervaporation separation of methanol mtbe and characterization of the polymer surfactant system
Journal of Membrane Science, 2001Co-Authors: Robert Y M Huang, Go Young Moon, Rajinder PalAbstract:Abstract For the separation of methanol/MTBE (methyl tert-butyl ether) mixtures, methanol selective chitosan composite membranes were prepared and tested for Pervaporation experiments. When anionic surfactants are added into the cationic chitosan solution, the solution viscosity was drastically decreased due to the collapsed chain conformation. Pervaporation characteristics of surfactant modified chitosan membrane were substantially improved due to the decreased membrane thickness and possible enhanced affinity to methanol. Rheological data of the casting solution was measured using viscometer and the surface morphology of the surfactant complexed chitosan membrane was investigated by atomic force microscopy (AFM).
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Pervaporation separation of ethyl butyrate and isopropanol with polyether block amide peba membranes
Journal of Membrane Science, 2000Co-Authors: Panida Sampranpiboon, Xianshe Feng, Ratana Jiraratananon, Dudsadee Uttapap, Robert Y M HuangAbstract:Abstract Polyether block amide (PEBA) membranes were prepared by the solution casting technique. The membranes were investigated for the Pervaporation separation of isopropanol–water and ethyl butyrate–water mixtures. The effects of feed concentration and temperature on the separation performance of the membranes were studied. The overall performance of Pervaporation separation was evaluated in term of the Pervaporation separation index (PSI), which is a composite parameter combining permeation flux and separation factor. It was shown that under the same operating conditions, the Pervaporation separation of aqueous ethyl butyrate solution was more efficient than the separation of aqueous isopropanol solutions. It was observed that both permeation flux and separation factor increased with an increase in feed ethyl butyrate content, while an increase in temperature resulted in an increase in permeation flux and a reduction in separation factor.
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characteristics of sodium alginate membranes for the Pervaporation dehydration of ethanol water and isopropanol water mixtures
Journal of Membrane Science, 1999Co-Authors: Robert Y M Huang, Rajinder Pal, Go Young MoonAbstract:Alginate membranes for the Pervaporation dehydration of ethanol–water and isopropanol–water mixtures were prepared and tested. The sodium alginate membrane was water soluble and mechanically weak but it showed promising performance for the Pervaporation dehydration. To control the water solubility the sodium alginate membrane was crosslinked ionically using various divalent and trivalent ions. Among them the alginate membrane crosslinked with Ca2+ ion showed the highest Pervaporation performance in terms of the flux and separation factors.
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Pervaporation with chitosan membranes ii blend membranes of chitosan and polyacrylic acid and comparison of homogeneous and composite membrane based on polyelectrolyte complexes of chitosan and polyacrylic acid for the separation of ethanol water mix
Journal of Membrane Science, 1997Co-Authors: Jyhjeng Shieh, Robert Y M HuangAbstract:Abstract Three different types of blend membranes based on chitosan and polyacrylic acid were prepared from homogeneous polymer solution and their performance on the Pervaporation separation of water-ethanol mixtures was investigated. It was found that all membranes are highly water-selective. The temperature dependence of membrane permselectivity for the feed solutions of higher water content (>30 wt%) was unusual in that both permeability and separation factor increased with increase in temperature. This phenomenon might be explained from the aspect of activation energy and suggested that the sorption contribution to activation energy of permeation should not always be ignored when strong interaction occurs in the Pervaporation membrane system. A comparison of Pervaporation performance between composite and homogeneous membranes was also studied. Typical Pervaporation results at 30°C for a 95 wt% ethanol aqueous solution were: for the homogeneous membrane, permeation flux = 33 g/m 2 h, separation factor = 2216; and for the composite membrane, permeation flux = 132 g/m 2 h, separation factor = 1008. A transport model consisting of dense layer and porous substrate in series was developed to describe the effect of porous substrate on Pervaporation performance.
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liquid separation by membrane Pervaporation a review
Industrial & Engineering Chemistry Research, 1997Co-Authors: Xianshe Feng, Robert Y M HuangAbstract:Pervaporation is one of the most active areas in membrane research, and the Pervaporation process has been shown to be an indispensable component for chemical separations. In this paper, the recent development in Pervaporation membranes and Pervaporation processes is reviewed, and some outstanding questions involved in membrane Pervaporation are discussed with emphasis on the following issues: mass transport in the membrane, membrane material selection, concentration polarization in the boundary layer, pressure buildup in hollow fiber membranes, asymmetric and composite membranes, and the activation energy for permeation. We attempt to provide insight into this dynamic field and to highlight some of the outstanding problems yet to be solved or clarified.
Zongli Xie - One of the best experts on this subject based on the ideXlab platform.
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study of hybrid pva ma teos Pervaporation membrane and evaluation of energy requirement for desalination by Pervaporation
International Journal of Environmental Research and Public Health, 2018Co-Authors: Zongli Xie, Manh Hoang, Jianhua Zhang, Stephen K GrayAbstract:Desalination by Pervaporation is a membrane process that is yet to be realized for commercial application. To investigate the feasibility and viability of scaling up, a process engineering model was developed to evaluate the energy requirement based on the experimental study of a hybrid polyvinyl alcohol/maleic acid/tetraethyl orthosilicate (PVA/MA/TEOS) Pervaporation Membrane. The energy consumption includes the external heating and cooling required for the feed and permeate streams, as well as the electrical power associated with pumps for re-circulating feed and maintaining vacuum. The thermal energy requirement is significant (e.g., up to 2609 MJ/m3 of thermal energy) and is required to maintain the feed stream at 65 °C in recirculation mode. The electrical energy requirement is very small (<0.2 kWh/m3 of required at 65 °C feed temperature at steady state) with the vacuum pump contributing to the majority of the electrical energy. The energy required for the Pervaporation process was also compared to other desalination processes such as Reverse Osmosis (RO), Multi-stage Flash (MSF), and Multiple Effect Distillation (MED). The electrical energy requirement for Pervaporation is the lowest among these desalination technologies. However, the thermal energy needed for Pervaporation is significant. Pervaporation may be attractive when the process is integrated with waste heat and heat recovery option and used in niche applications such as RO brine concentration or salt recovery.
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Study of Hybrid PVA/MA/TEOS Pervaporation Membrane and Evaluation of Energy Requirement for Desalination by Pervaporation
MDPI AG, 2018Co-Authors: Zongli Xie, Manh Hoang, Jianhua Zhang, Stephen GrayAbstract:Desalination by Pervaporation is a membrane process that is yet to be realized for commercial application. To investigate the feasibility and viability of scaling up, a process engineering model was developed to evaluate the energy requirement based on the experimental study of a hybrid polyvinyl alcohol/maleic acid/tetraethyl orthosilicate (PVA/MA/TEOS) Pervaporation Membrane. The energy consumption includes the external heating and cooling required for the feed and permeate streams, as well as the electrical power associated with pumps for re-circulating feed and maintaining vacuum. The thermal energy requirement is significant (e.g., up to 2609 MJ/m3 of thermal energy) and is required to maintain the feed stream at 65 °C in recirculation mode. The electrical energy requirement is very small (<0.2 kWh/m3 of required at 65 °C feed temperature at steady state) with the vacuum pump contributing to the majority of the electrical energy. The energy required for the Pervaporation process was also compared to other desalination processes such as Reverse Osmosis (RO), Multi-stage Flash (MSF), and Multiple Effect Distillation (MED). The electrical energy requirement for Pervaporation is the lowest among these desalination technologies. However, the thermal energy needed for Pervaporation is significant. Pervaporation may be attractive when the process is integrated with waste heat and heat recovery option and used in niche applications such as RO brine concentration or salt recovery
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Desalination by Pervaporation: A review
Desalination, 2016Co-Authors: Qinzhuo Wang, Brian Bolto, Manh Hoang, Na Li, Zongli XieAbstract:Desalination via Pervaporation has the potential to be an efficient way of getting fresh water from non-potable saline sources with the advantages of a high rejection of salt and the capability of coping with high-salinity solutions. This overview of desalination via Pervaporation mainly focuses on membrane materials, transport mechanisms and the effect of operating parameters on PV performance. Almost all kinds of membranes ever reported in desalination are mentioned, including those based on polymers, inorganic materials and their hybrids, all of which show reasonably performance with adequate flux and excellent salt rejection. The comparison of Pervaporation with existing conventional reverse osmosis and membrane distillation processes and several strategies for further improvement of Pervaporation performance are discussed.
Gun Trägårdh - One of the best experts on this subject based on the ideXlab platform.
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the influence of process parameters on aroma recovery by hydrophobic Pervaporation
Desalination, 2006Co-Authors: Olivera Trifunovic, Frank Lipnizki, Gun TrägårdhAbstract:Hydrophobic Pervaporation has been shown to be a promising, alternative process for the recovery of volatile organic components from their aqueous solutions, such as the recovery of aroma compounds in the food industry. Until now most of the research on the influence of operating parameters on aroma recovery by Pervaporation has been conducted on the laboratory scale. The number of studies dealing with the scaling-up of the Pervaporation process for the separation of multi-component mixtures is still relatively small, and usually has a number of limitations. The aim of this study was to investigate module design aspects of Pervaporation, using a modified version of an existing Pervaporation simulation tool for aroma recovery. By applying the simulation to four aroma compounds, two alcohols and two esters, the influence of major process and module design parameters on the performance of a single module has been investigated. The results of the simulation show that detailed modelling of single module behaviour is an important aspect of the optimisation of Pervaporation plant performance.
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scale up of Pervaporation for the recovery of natural aroma compounds in the food industry part 1 simulation and performance
Journal of Food Engineering, 2002Co-Authors: Frank Lipnizki, Jenny Olsson, Gun TrägårdhAbstract:The possibility of using Pervaporation for the recovery of natural aroma compounds in the food industry has been widely recognised. The aim of this study was to build a bridge between experimental studies of multi-component systems and potential applications of Pervaporation in the food industry. Therefore, a novel process simulation of Pervaporation has been developed for multi-component mixtures. By applying this simulation to 10 aroma compounds of relevance in the food industry, the influence of process parameters such as permeate pressure, feed temperature, degree of aroma folding and membrane area, on the performance of Pervaporation has been investigated. Based on the results of the simulations, it has been demonstrated that process simulation can play an important role in integrating and optimising Pervaporation in the food industry.
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Pervaporation of dilute organic waters mixtures a literature review on modelling studies and applications to aroma compound recovery
Journal of Membrane Science, 1993Co-Authors: Hans O.e. Karlsson, Gun TrägårdhAbstract:Abstract Pervaporation as a tool for the removal of organic substances from dilute aqueous solutions has been reviewed. During Pervaporation the membrane governs the performance of the process. The removal of organics from water is accomplished with membranes made of elastomeric or hydrophobic polymer materials. The performance of these membranes, measured as fluxes and enrichment factors, differs considerably. Total fluxes vary between 24 and 2728 g/m2-hr while the enrichment factor varies between 0.6 and 372. Modelling of the process involves four successive steps, a mass transfer from the bulk of the feed to the feed-membrane interface, partition of the penetrants between the feed and the membrane, diffusion in the membrane and desorption at the membrane-permeate interface. All these steps are crucial for the overall performance of the process. Several models with different approaches and validities exist for each step. The possible of Pervaporation for aroma compound recovery has been verified in a number of studies. These studies indicate that aroma compounds, especially volatile aroma compounds, can be enriched several hundreds of times with Pervaporation and that the process could be profitable.
Taishung Chung - One of the best experts on this subject based on the ideXlab platform.
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recent membrane development for Pervaporation processes
Progress in Polymer Science, 2016Co-Authors: Yee Kang Ong, Taishung Chung, Gui Min Shi, Yu Pan Tang, Jian Zuo, Suzana Pereira NunesAbstract:Abstract Pervaporation has been regarded as a promising separation technology in separating azeotropic mixtures, solutions with similar boiling points, thermally sensitive compounds, organic–organic mixtures as well as in removing dilute organics from aqueous solutions. As the Pervaporation membrane is one of the crucial factors in determining the overall efficiency of the separation process, this article reviews the research and development (R&D) of polymeric Pervaporation membranes from the perspective of membrane fabrication procedures and materials.
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pebax poss mixed matrix membranes for ethanol recovery from aqueous solutions via Pervaporation
Journal of Membrane Science, 2011Co-Authors: Ngoc Lieu Le, Taishung ChungAbstract:Abstract Novel mixed matrix membranes made of polyether-block-amide/polyhedral oligosilsesquioxane (Pebax/POSS) have been developed and investigated in this study for ethanol recovery via Pervaporation separation. Two types of POSS; namely, octa(3-hydroxy-3-methylbutyldimethylsiloxy) (AL0136) and disilanolisobutyl (SO1440), were incorporated into Pebax membranes. The effects of POSS loading, feed ethanol concentration and feed temperature on Pervaporation performance of the newly developed mixed matrix membranes (MMMs) have been studied. The incorporation of POSS nanoparticles improve the Pervaporation performance of the hybrid membranes significantly. At 2 wt.% POSS loading, both permeation flux and separation factor of ethanol/water reach maximum values, which are 183.5 g/m 2 h and 4.6 for Pebax/AL0136 and 125.8 g/m 2 h and 4.1 for Pebax/SO1440, respectively. Pebax/AL0136 MMMs give better performance than Pebax/SO1440 MMMs, probably due to its higher affinity towards ethanol. Experimental results show that an increase in feed ethanol concentration results in an increase in flux, but decreases in separation factor and membrane selectivity. Flux increases but permeability decreases with an increase in operating temperature due to the increase in driving forces and the reduction in permeant sorption, respectively. Separation factor and selectivity are also observed to increase with increasing operating temperature. The changes in driving force, cluster formation, membrane swelling and interaction among permeating molecules play essential roles for the observed trends. This work may provide useful insights of mixed matrix membranes, especially those containing POSS for Pervaporation recovery applications.
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processing and engineering of Pervaporation dehydration of ethylene glycol via dual layer polybenzimidazole pbi polyetherimide pei membranes
Journal of Membrane Science, 2011Co-Authors: Yan Wang, Taishung Chung, Michael GruenderAbstract:Abstract Operating conditions play a significant role in determining the separation performance of a Pervaporation process, because they not only manipulate the driving forces to transport permeants but also affect the physicochemical properties of the Pervaporation membrane itself. In this study, fundamental governing equations have been derived to correlate separation performance with system operation conditions and intrinsic separation characteristics of the Pervaporation membrane. Polybenzimidazole/polyetherimide (PBI/PEI) dual-layer hollow fiber membranes were chosen to study the Pervaporation dehydration of ethylene glycol (EG) under different testing protocols. The effects of operational parameters such as operation temperature, permeate pressure, feed composition and operation duration on performance indicators (flux and separation factor, permeance and selectivity) have been investigated. Experimental results show that an increase in operation temperature results in an increase in flux and selectivity, but a decrease in permeance and separation factor. In addition to other factors, decreasing sorption, less EG–water clusters and lower membrane-EG affinity with increasing temperature, play essential roles for the opposite trends. Both flux and permeance decrease with an increase in permeate pressure, while both separation factor and selectivity have an up-and-down trend. An increase in EG composition in the feed from 50 to 90 wt.% results in a lower water flux and permeance, but EG flux and permeance first increase and then decrease. This is due to the combined effect of water-induced membrane swelling and the formation of an EG boundary layer upon the membrane surface. The long-term test up to 33 days proves the membrane durability for EG dehydration. This work may provide useful insights to Pervaporation fundamentals, system design and scale up for the EG dehydration.
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polyimides membranes for Pervaporation and biofuels separation
Progress in Polymer Science, 2009Co-Authors: Taishung Chung, Yan Wang, Lan Ying Jiang, Xiang Yi Qiao, Junyih LaiAbstract:Abstract Pervaporation is the most promising technology in the molecular-scale liquid/liquid separations existing in biorefinery, petrochemical, pharmaceutical industries, etc. for being highly selective, economical, safe and ecofriendly. However, the inadequacy of the existing polymeric membranes hinders the full exploitation of the application opportunities on the industrial-scale. This situation has motivated a substantial amount of work to explore diverse polymers and their efficiency in current and potential Pervaporation fields. Due to the various attractive properties of polyimides as compared to other polymers, this review article is especially contributed to provide a comprehensive overview on the current state-of-art technologies for polyimides membranes in Pervaporation. As an indispensible orientation for development of Pervaporation, firstly the transport mechanisms and some other fundamentals of Pervaporation were introduced.Thereafter, the pros and cons of the various facets of polyimides for Pervaporation application, from polymer synthesis, modification to membrane formation were analyzed. Finally, the superiority of polyimides over other polymers in separation property was highlighted. In the light of the anticipated role of polyimides as distinguished materials for Pervaporation, the future prospects were analyzed whereby to draw new guidelines for the further promotion of polyimides application in Pervaporation.
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investigation of the fundamental differences between polyamide imide pai and polyetherimide pei membranes for isopropanol dehydration via Pervaporation
Journal of Membrane Science, 2008Co-Authors: Yan Wang, Lan Ying Jiang, Takeshi Matsuura, Taishung ChungAbstract:Abstract Torlon ® 4000TF polyamide-imide (PAI) and Ultem ® 1010 polyetherimide (PEI) membranes were fabricated and studied for isopropanol dehydration by Pervaporation. The properties of these two materials and the membranes fabricated were tested and compared through different characterizations (DSC, TGA, Goniometer, X-ray diffraction, gas permeation, and water sorption). Compared with PEI dense membranes, PAI dense membranes show a much higher separation factor (up to 3000 at 60 °C) and comparable flux. Higher hydrophilicity, narrower d -space and higher water uptake of PAI membrane confirmed by above characterizations all contribute to its higher Pervaporation performance. The Pervaporation results of the asymmetric membranes show that the polymer concentration for membrane casting is very important. For both PAI and PEI membranes, dope concentrations equal to or higher than their critical concentrations are essential to produce useful Pervaporation membranes. In addition, heat treatment is needed to reduce defects and enhance separation performance. Different operation modes were also studied. The separation using a membrane with porous structure facing against the feed solution shows a much higher separation factor with only a slight decrease of flux. This important phenomenon is explained in terms of the balance between two major contradictory effects: concentration polarization and dense layer swelling.
Juin-yih Lai - One of the best experts on this subject based on the ideXlab platform.
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Poly(tetrafluoroethylene)/polyamide thin-film composite membranes via interfacial polymerization for Pervaporation dehydration on an isopropanol aqueous solution
Journal of Membrane Science, 2008Co-Authors: Ying-ling Liu, Juin-yih LaiAbstract:Abstract Poly(tetrafluoroethylene)/polyamide (PTFE/PA) thin-film composite membranes were prepared via interfacial polymerization using surface-modified PTFE films as substrates. The composite membranes from the amine-functionalized PTFE films exhibit good layer compatibility and membrane stability due to the formation of covalent linkages between the PTFE substrate and PA layer. The composite membranes are applied to Pervaporation dehydration processes on a 70 wt% isopropanol aqueous solution. The membranes are stable under the Pervaporation dehydration operations and show a high-permeation flux of 1720 g/h m 2 and a separation factor of 177. These PTFE-based thin-film composite membranes are potentially useful in Pervaporation separation for other organic mixtures.
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hydrophilic surface grafted poly tetrafluoroethylene membranes using in Pervaporation dehydration processes
Journal of Membrane Science, 2006Co-Authors: Ying-ling Liu, Kueirrarn Lee, Juin-yih LaiAbstract:Abstract Preparation of hydrophilic poly(tetrafluoroethylene) (PTFE) membranes was performed by means of combined hydrogen plasma and ozone treatment and surface-initiating grafting polymerization. Acrylamide (AAm) and sodium 4-styrenesulfonate (NaSS) were used as monomers in grafting polymerization. Grafted PTFE membrane exhibited high hydrophilicity with a water contact angle of 38° and showed superior performance of Pervaporation dehydration for various aqueous solutions of organic compounds. A high permeation flux of 422 g/m 2 h and a high separation factor of 4491 were observed with PTFE-g-PSSA membrane in Pervaporation dehydration of a 90 wt.% aqueous solution of isopropanol (IPA) at 65 °C. The PTFE-g-PSSA membrane also exhibits advantages of wide application scopes, low temperature-sensitivity, good membrane stability, and operation durability in Pervaporation dehydration processes.
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Pervaporation of water alcohol mixtures through chitosan cellulose acetate composite hollow fiber membranes
Journal of Applied Polymer Science, 2004Co-Authors: H A Tsai, H C Chen, Wenli Chou, K R Lee, Mingchien Yang, Juin-yih LaiAbstract:For the purpose of separating aqueous alcohol by the use of Pervaporation technique, a composite membrane of chitosan (CT) dip-coated cellulose acetate (CA) hollow-fiber membranes, CT-d-CA, was investigated. The effects of air-gap distance in the spinning of CA hollow-fiber membranes, chitosan concentration, and sorts of aqueous alcohol solutions on the Pervaporation performances were studied. Compared with unmodified CA hollow-fiber membrane, the CT-d-CA composite hollow-fiber membrane effectively increases the permselectivity of water. The thickness of coating layer increases with an increase in chitosan concentration. As the concentration of chitosan solution increased, the permeation rate decreased and the concentration of water in the permeate increased. In addition, the effects of feed composition and feed solution temperature on the Pervaporation performances were also investigated. The permeation rate and water content in permeate at 25°C for a 90 wt % aqueous isopropanol solution through the CT-d-CA composite hollow-fiber membrane with a 5-cm air-gap distance spun, 2 wt % chitosan dip-coated system were 169.5 g/m 2 h and 98.9 wt %, respectively.