scholarly journals Performance of a pervaporation system for the separation of an ethanol-water mixture using fractional condensation

2018 ◽  
Vol 77 (7) ◽  
pp. 1861-1869 ◽  
Author(s):  
Jie Liu ◽  
Jiding Li ◽  
Quan Chen ◽  
Xiaoduan Li
Keyword(s):  
Flow Velocity ◽  
Separation Factor ◽  
Polyvinylidene Fluoride ◽  
Separation Efficiency ◽  
Composite Membranes ◽  
Total Flux ◽  
Water Mixture ◽  
Term Operation ◽  
Fractional Condensation ◽  
Feed Temperature

Abstract Polydimethylsiloxane (PDMS)/polyvinylidene fluoride (PVDF) composite membranes were fabricated and subsequently applied in ethanol recovery from an ethanol-water mixture by pervaporation (PV) using fractional condensation. The effects of feed temperature and feed flow velocity on the pervaporative properties of PDMS/PVDF composite membranes were investigated. Scanning electron microscopy (SEM) results showed that PDMS was coated uniformly on the surface of porous PVDF substrate, and the PDMS separation layer was dense with a thickness of 1.7 µm. Additionally, it was found that with increasing feed temperature, the total flux of the composite membrane increased, whereas the separation factor decreased. As the feed flow velocity increased, the total flux and separation factor increased. Besides, the permeate vapor was condensed by a two-stage fractional condenser maintained at different temperatures. The effects of the condensation conditions on fractions of ethanol-water vapor were studied to concentrate ethanol in product. The fractional condensers proved to be an effective way to enhance the separation efficiency. Under the optimum fractional condensation conditions, the second condenser showed a flux of 1,329 g/m2 h and the separation factor was increased to 17.2. Furthermore, the long-term operation stability was verified, indicating that the PV system incorporating fractional condensation was a promising approach to separate ethanol from the ethanol-water mixture.

scholarly journals VTOS Cross-Linked PDMS Membranes for Recovery of Ethanol from Aqueous Solution by Pervaporation

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Jin Gu ◽  
Yunxiang Bai ◽  
Lin Zhang ◽  
Lirong Deng ◽  
Chunfang Zhang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Separation Factor ◽  
Pdms Membrane ◽  
Total Flux ◽  
Cross Linking ◽  
High Separation Factor ◽  
Ethanol Aqueous Solution ◽  
High Ethanol ◽  
Feed Temperature ◽  
High Separation

PDMS membranes were prepared by cross-linking with vinyltriethoxysilane (VTOS) on polyacrylonitrile (PAN) substrate to increase hydrophobicity and improve pervaporation (PV) performance. It was shown that the membranes had high ethanol permselectivity and flux. The effects of cross-linking temperature, the content of cross-linking agent, and feed temperature on PV performance of VTOS cross-linked PDMS membranes were investigated. For 6 wt% ethanol aqueous solution, the PDMS membrane had the high separation factor of 15.5 and total flux 573.3 g·m−2·h−1, respectively, when the feed temperature was 40°C, H-PDMS : VTOS : DBTDL = 1 : 0.2 : 0.02 and cross-linking temperature was 80°C.

scholarly journals Blended Chitosan and Polyvinyl Alcohol Membrane for Pervaporation Separation Methanol/Methyl tert-Butyl Ether Mixture. (II) Effect of Operating Parameters

2013 ◽  
Vol 65 (1) ◽  
Author(s):  
M. G. Mohd Nawawi ◽  
Zafifah Zamrud ◽  
Z. Idham ◽  
O. Hassan ◽  
N. Mohd Sakri
Keyword(s):  
Polyvinyl Alcohol ◽  
Separation Factor ◽  
Composite Membranes ◽  
Methyl Tert Butyl Ether ◽  
Butyl Ether ◽  
Blend Membrane ◽  
Membrane Flux ◽  
Ether Mixture ◽  
Feed Temperature ◽  
Pervaporation Separation

Blend chitosan and polyvinyl alcohol (PVA) composite membranes were developed by mixing PVA and chitosan solutions at appropriate ratios. Pervaporation separation of the membrane was tested for methanol and MTBE mixture at different feed concentrations and temperature. The pervaporation performances were studied and evaluated and compared to the composite chitosan membrane. Flux increased with the increasing concentration of methanol in the feed. Separation factor was highest for the 20 wt% chitosan-containing blend membrane. The blend membrane containing 20-40 wt% of chitosan at feed temperature of 50⁰C exhibited permeation flux in between 52.28 g/m2.hr to 66.92 g/m2.hr with the separation factor of 53.22 to 81.00. 

The pervaporation performance and mass transfer process of PDMS membranes for acetic acid/water mixture

e-Polymers ◽  
2011 ◽  
Vol 11 (1) ◽  
Author(s):  
Housheng Hong ◽  
Longxiang Chen ◽  
Qingwen Zhang ◽  
Tao You
Keyword(s):  
Mass Transfer ◽  
Acetic Acid ◽  
Separation Factor ◽  
Mass Transfer Process ◽  
Silica Content ◽  
Acid Water ◽  
Water Mixture ◽  
Acetic Acid Water ◽  
And Performance ◽  
Feed Temperature

AbstractPolydimethylsiloxane (PDMS) membranes with different silica content were prepared without support. The characterization and performance of the membranes were investigated by scanning electron microscope (SEM), thermogravimetry analysis (TGA), contact angle meter and swelling experiment. The pervaporation process was investigated with acetic acid/water mixture. And the process of mass transfer was analysed depending on the solution-diffusion model. The addition of silica could greatly improve the pervaporation flux and enhance the thermal stability of membrane. With an increase in feed temperature, selectivity decreased and permeation flux increased for the unfilled PDMS membrane. However, the separation factor of silica loading of 10 wt. % membranes, exhibited a maximum at 50 °C, and it was higher than unfilled membrane when feed temperature was above 40 °C. With the enhancement of acetic acid concentration, flux and separation factor increased. And the unfilled membrane and the silica filled membrane were prior permeation membranes for water when the downstream pressure of unfilled membrane and silica filled membrane was over 1000 Pa and 1500 Pa respectively.

scholarly journals Pervaporation dehydration of ethanol-water mixture using crosslinked poly(vinyl alcohol) membranes

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
Keyword(s):  
Separation Factor ◽  
Vinyl Alcohol ◽  
Composite Membranes ◽  
Poly Vinyl Alcohol ◽  
Separation Performance ◽  
Crosslinking Reaction ◽  
Permeation Flux ◽  
Water Mixture ◽  
Chemical Structures ◽  
Crosslinking Agents

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.

scholarly journals Enhancing Pervaporation Membrane Selectivity by Incorporating Star Macromolecules Modified with Ionic Liquid for Intensification of Lactic Acid Dehydration

Polymers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1811
Author(s):  
Valeriia Rostovtseva ◽  
Alexandra Pulyalina ◽  
Roman Dubovenko ◽  
Ilya Faykov ◽  
Kseniya Subbotina ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Lactic Acid ◽  
Polymer Matrix ◽  
Separation Factor ◽  
Membrane Structure ◽  
High Performance ◽  
Separation Efficiency ◽  
Pharmaceutical Chemical ◽  
Permeate Flux ◽  
Membrane Components

Modification of polymer matrix by hybrid fillers is a promising way to produce membranes with excellent separation efficiency due to variations in membrane structure. High-performance membranes for the pervaporation dehydration were produced by modifying poly(2,6-dimethyl-1,4-phenylene oxide) (PPO) to facilitate lactic acid purification. Ionic liquid (IL), heteroarm star macromolecules (HSM), and their combination (IL:HSM) were employed as additives to the polymer matrix. The composition and structure of hybrid membranes were characterized by X-ray diffraction and FTIR spectroscopy. Scanning electron microscopy was used to investigate the membranes surface and cross-section morphology. It was established that the inclusion of modifiers in the polymer matrix leads to the change of membrane structure. The influence of IL:HSM was also studied via sorption experiments and pervaporation of water‒lactic acid mixtures. Lactic acid is an essential compound in many industries, including food, pharmaceutical, chemical, while the recovering and purifying account for approximately 50% of its production cost. It was found that the membranes selectively remove water from the feed. Quantum mechanical calculations determine the favorable interactions between various membrane components and the liquid mixture. With IL:HSM addition, the separation factor and performance in lactic acid dehydration were improved compared with pure polymer membrane. The best performance was found for (HSM: IL)-PPO/UPM composite membrane, where the permeate flux and the separation factor of about 0.06 kg m−2 h−1 and 749, respectively, were obtained. The research results demonstrated that ionic liquids in combination with star macromolecules for membrane modification could be a promising approach for membrane design.

Separation of Dimethylformamide/H2O Mixtures Using Pervaporation-Distillation Hybrid Process

2011 ◽  
Vol 233-235 ◽  
pp. 866-869 ◽  
Author(s):  
Guang Lu Han ◽  
Qi Zhang ◽  
Jing Zhong ◽  
Hui Shao ◽  
Huan Ru Zhang
Keyword(s):  
Aqueous Solution ◽  
Separation Factor ◽  
Aspen Plus ◽  
Composite Membranes ◽  
Hybrid Process ◽  
Hybrid Processes ◽  
Operation Temperature ◽  
The Cost

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

A facile fabrication of superhydrophobic and superoleophilic adsorption material 5A zeolite for oil–water separation with potential use in floating oil

Open Physics ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 486-493
Author(s):  
Ting Liang ◽  
Biao Wang ◽  
Zhenzhong Fan ◽  
Qingwang Liu
Keyword(s):  
Separation Efficiency ◽  
Particle Size Analysis ◽  
Size Analysis ◽  
Water Mixture ◽  
Water Separation ◽  
Oil Sorbent ◽  
Analysis Experiment ◽  
5A Zeolite ◽  
Oil Water ◽  
Potential Use

Abstract A facile method for fabricating superhydrophobic and superoleophilic powder with 5A zeolite and stearic acid (SA) is reported in this study. The effect of different contents of SA on contact angle (CA) was investigated. The maximum water CA was 156.2°, corresponding to the optimum SA content of 1.5 wt%. The effects of SA and the mechanism of modified 5A zeolite powder by SA were analyzed by sedimentation analysis experiment, FTIR analysis, particle size analysis, and SEM characterization. The SA-modified 5A zeolite was used as an oil sorbent to separate oil–water mixture with potential use in floating oil. The separation efficiency was above 98%.

Preparation of Silicalite-1 Membranes with Seeding Method and its Separation Performance for Low Ethanol/Water Mixture

2013 ◽  
Vol 807-809 ◽  
pp. 591-595
Author(s):  
Hong Liang Chen ◽  
Ji Song Yang ◽  
Yan Wang ◽  
Hui Ying Li ◽  
Xin Xin Li ◽  
...  
Keyword(s):  
Hydrothermal Synthesis ◽  
Separation Factor ◽  
High Performance ◽  
Separation Performance ◽  
Water Mixture ◽  
Synthesis Conditions ◽  
Seeding Method

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.

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