Dehydration of water/pyridine mixtures by pervaporation using cellulose acetate/ polyacrylonitrile blend membrane

2011 ◽  
Vol 63 (8) ◽  
pp. 1695-1700 ◽  
Author(s):  
J. H. Lv ◽  
G. M. Xiao

Cellulose acetate/ polyacrylonitrile (CA/PAN) membranes were prepared and used to separate pyridine / water mixtures by pervaporation. The membranes were characterized through SEM. The effects of feed concentration, operation temperature and downstream pressure on the separation performance were evaluated. Experimental results indicated the increase of operation temperature could raise the permeation flux and the separation factor, while increasing feed concentration and downstream pressure would raise the separation factor and decrease the permeation flux. Under the conditions that pyridine solution was 99 wt.%, operation temperature was 323 K and downstream pressure was 20 mmHg, the CA/PAN blend membrane showed its best separation performance that the permeation flux was 56 · g · m−2 h−1 and the separation factor was 182.

2012 ◽  
Vol 550-553 ◽  
pp. 3004-3007 ◽  
Author(s):  
Verawat Champreda ◽  
David Stuckey ◽  
Apichat Boontawan

The composite polydimethylsiloxane PERVAPTM 4060 was used for separation of methanol/water solutions by using pervaporation technique. The effect of feed concentration, feed temperature, and feed flow rate were investigated for the separation performance. The experimental data showed that increasing of the feed methanol concentration from 0.5 to 10 wt% resulted in an increase in total permeation flux up for to 35 % whilst the separation factor (α) decreased by 85%. The results also showed that increasing operating temperature from 40 to 60 °C caused an increases in methanol permeance up to 130%.


Membranes ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 627
Author(s):  
Ayumi Ikeda ◽  
Chie Abe ◽  
Wakako Matsuura ◽  
Yasuhisa Hasegawa

The separation of non-aqueous mixtures is important for chemical production, and zeolite membranes have great potential for energy-efficient separation. In this study, the influence of the framework structure and composition of zeolites on the permeation and separation performance of methanol through zeolite membranes were investigated to develop a methanol permselective zeolite membrane. As a result, the FAU-type zeolite membrane prepared using a solution with a composition of 10 SiO2:1 Al2O3:17 Na2O:1000 H2O showed the highest permeation flux of 86,600 μmol m−2 s−1 and a separation factor of 6020 for a 10 wt% methanol/methyl hexanoate mixture at 353 K. The membrane showed a molecular sieving effect, reducing the single permeation flux of alcohol with molecular size for single-component alcohols. Moreover, the permeation flux of methanol and the separation factor increased with an increase in the carbon number of the alcohols and methyl esters containing 10 wt% methanol. In this study, the permeation behavior of FAU-type zeolite membranes was also discussed based on permeation data. These results suggest that the FAU-type zeolite membrane has the potential to separate organic solvent mixtures, such as solvent recycling and membrane reactors.


2016 ◽  
Vol 19 (4) ◽  
pp. 97-106
Author(s):  
Hai Le Tran ◽  
Minh Ngoc Duy Vuu ◽  
Quan Minh Hoang ◽  
Nguyen Thi Nguyen ◽  
Phong Thanh Mai

Crosslinked poly(vinyl alcohol) (PVA) composite membranes were synthesized by casting selective crosslinked PVA films on the polyacrylonitrile (PAN) porous substrates. The PVA films were prepared by in-situ crosslinking technique using four different crosslinking agents, such as glutaraldehyde, fumaric acid, maleic acid and malic acid. The separation performance in terms of permeation flux and separation factor of prepared membranes were evaluated for pervaporation dehydration of ethanol/water mixture of 80/20 wt% at 60 oC. The prepared membranes were also characterized by FTIR, SEM, swelling and sessile drop contact angle measurements. It was found that the chemical structure of the PVA membrane was changed via crosslinking reaction. The physicochemical properties (hydrophilicity and swelling degree) and separation performance of the prepared membranes were affected by the chemical structures of the crosslinking agents. Furthermore, there was a trade-off between permeation flux and selectivity of the resulting membranes. When the flux increased, the separation factor decreased. The results of this study contributed to enrich the data of the crosslinking reaction of PVA membranes, and expected to help researcher in suitable choosing crosslinking agent for producing pervaporation PVA membrane for dehydration of ethanol solutions.


2011 ◽  
Vol 63 (12) ◽  
pp. 2820-2826 ◽  
Author(s):  
Majid Aliabadi ◽  
Abdolreza Aroujalian ◽  
Ahmadreza Raisi

This study describes the successful separation of acrylonitrile (ACN) from dilute aqueous streams using pervaporation process. The influences of ACN feed concentration, permeate pressure, operating temperature, feed flow rate and membrane thickness on the membrane separation performance were investigated. The results showed that with an increase in ACN concentration in the feed solution, the permeation flux of ACN increased while the enrichment factor decreased. It was also indicated that increasing the permeate pressure reduced the driving force for mass transfer and consequently the permeation flux dropped while the enrichment factor enhanced. Polydimethylsiloxane membranes used in this study showed very good properties in the separation process, leading to enrichment factors in the range of 70–140. Furthermore, the activation energy for pervaporation of both ACN and water calculated from Arrhenius plot indicated that the permeation of water through the membrane was more temperature dependant than ACN.


2014 ◽  
Vol 700 ◽  
pp. 466-469
Author(s):  
Ke Ma ◽  
Yu Yun Fu

The pervaporation membranes were prepared by using poly dimethyl siloxane (PDMS) as precursor, toluene as solvent, triethoxy methylsilane as cross linker, dibutyltin dilaurate as catalyst. The PDMS membranes were evaluated with permeation flux and separation factor. The effects of cross linker dosage and the operation parameters during the process of pervaporation were investigated. It was shown from the results that: The selectivity of the membranes increased while the permeation flux first increased and then decreased as the linker dosage increased; the selectivity of the membranes decreased while the permeation flux increased as the feed temperature increased; the selectivity and the permeation flux of the membranes both increased as the feed concentration increased; the selectivity and the flux also both increased as the feed flow rate increased; the selectivity increased while the permeation flux decreased as the separation press increased. When the proportion of the PDMS, solvent, cross linker and catalyst were immobile, The permeation flux and separation factor could be 98mg/(m2·h) and 5.12 when the feed temperature was 60°C, feed concentration was 0.5g/L, feed flow rate was 0.6L/min and separation press was 6KPa.


Membranes ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 429
Author(s):  
Aurelia Cristina Nechifor ◽  
Andreia Pîrțac ◽  
Paul Constantin Albu ◽  
Alexandra Raluca Grosu ◽  
Florina Dumitru ◽  
...  

The separation, concentration and transport of the amino acids through membranes have been continuously developed due to the multitude of interest amino acids of interest and the sources from which they must be recovered. At the same time, the types of membranes used in the sepa-ration of the amino acids are the most diverse: liquids, ion exchangers, inorganic, polymeric or composites. This paper addresses the recuperative separation of three amino acids (alanine, phe-nylalanine, and methionine) using membranes from cellulosic derivatives in polypropylene ma-trix. The microfiltration membranes (polypropylene hollow fibers) were impregnated with solu-tions of some cellulosic derivatives: cellulose acetate, 2-hydroxyethyl-cellulose, methyl 2-hydroxyethyl-celluloseand sodium carboxymethyl-cellulose. The obtained membranes were characterized in terms of the separation performance of the amino acids considered (retention, flux, and selectivity) and from a morphological and structural point of view: scanning electron microscopy (SEM), high resolution SEM (HR-SEM), Fourier transform infrared spectroscopy (FT-IR), energy dispersive spectroscopy (EDS) and thermal gravimetric analyzer (TGA). The re-sults obtained show that phenylalanine has the highest fluxes through all four types of mem-branes, followed by methionine and alanine. Of the four kinds of membrane, the most suitable for recuperative separation of the considered amino acids are those based on cellulose acetate and methyl 2-hydroxyethyl-cellulose.


Membranes ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 65
Author(s):  
Xueru Yan ◽  
Alexandre Favard ◽  
Stéphane Anguille ◽  
Marc Bendahan ◽  
Philippe Moulin

Membrane processes are promising methods to separate gases from feed streams without phase changing. A hybrid process, the combination of ionic liquids with a ceramic membrane (ILM), has been developed for humidity removal in a green continuous process. This new concept provides a more efficient and available ionic liquid (IL)-based membrane regeneration process, which just switches the moist feed stream to dry air. Furthermore, the ILM presents high stability and mechanical resistance during long-time operation. In addition, the influences of several operating parameters, including flow rate, temperature, absolute pressure, and feed concentration on process efficiency were investigated. The lower inlet flow rate was found to be favorable for drying humid air. Moreover, when the pressure increased, the mass of absorbed water was increased, while the feed concentration had no significant effects on the membrane separation performance. However, the operating temperature had a great effect on humidity removal. It is necessary to note that the processes at room temperature can limit the energy consumption. The absorbing process of ILM remained efficient after several absorption desorption cycles. Therefore, the new ILM hybrid process that has been developed has great potential for consecutive humidity removal processes.


2011 ◽  
Vol 233-235 ◽  
pp. 866-869 ◽  
Author(s):  
Guang Lu Han ◽  
Qi Zhang ◽  
Jing Zhong ◽  
Hui Shao ◽  
Huan Ru Zhang

Three kinds of commercial PVA composite membranes with different crosslinking degrees (PVA-1, PVA-2 and PVA-3) were used to separate DMF/H2O mixtures. Their pervaporation performance was investigated at different operation temperatures. The results showed that PVA-1 was the most suitable one for separating DMF/H2O mixtures. When operation temperature was 60°C and downstream pressure was lower than 6kPa, flux reached to 0.59 kg·m-2·h-1 and separation factor was 33 for PVA-1 membranes. Aspen Plus® was applied to simulate the normal distillation for retentate from pervaporation unit. Comparing with the two-effect distillation, the cost of concentrating DMF could be reduced 16.2% to 19.2% for DMF aqueous solution with different composition by hybrid processes. The cost would be the lowest for a hybrid process that concentrated the feed into 50wt% by pervaporation firstly, then concentrated retentate to 99.6wt% by two-effect distillation


2013 ◽  
Vol 807-809 ◽  
pp. 591-595
Author(s):  
Hong Liang Chen ◽  
Ji Song Yang ◽  
Yan Wang ◽  
Hui Ying Li ◽  
Xin Xin Li ◽  
...  

High performance silicalite-1 membranes were successfully synthesized on silica tubes by seeding method after filling the tubes with water and glycerol mixtures. After seeding the silica tubes with 200 nm seeds, all the silicalite-1 membranes show acceptable separation performance towards ethanol/water mixture after 4-12 h hydrothermal synthesis, and the highest flux of membrane with 8 h hydrothermal synthesis reaches about 0.98 kg/m2.h and the separation factor reaches about 60 towards 3 wt.% ethanol/water mixture. This result shows that the as-synthesized silicalite-1 membrane can concentrate the ethanol from 3% to about 65%, and the ethanol can be obtained over 600 g/m2.h by using the silicalite-1 membrane, which shows that seeding method and suitable control of synthesis conditions is possible for preparing high-performance silicalite-1 membranes.


2013 ◽  
Vol 634-638 ◽  
pp. 382-385
Author(s):  
Ke Guo Liu ◽  
Li Li Gu ◽  
Hui Guang Hu ◽  
Rong Yang ◽  
Jun Tao

The experimental studies for purification of 1,8-cineole by vacuum batch distillation as well as the application of additives in 1,8-cineole purification were carried out. There were two steps during the purification. In the first step, experimental results showed that the optimal operation conditions for purification of 1,8-cineole were the temperature of the reboiler at about 320.15 K under a certain vacuum degree. In the second step, the optimal operation temperature of the reboiler was 331.15 K. The optimal reflux ratio was generated finally. Vacuum degree was controlled between 1.1 kPa and 1.3 kPa.


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