Pervaporative removal of acrylonitrile from aqueous streams through polydimethylsiloxane membrane

2011 ◽  
Vol 63 (12) ◽  
pp. 2820-2826 ◽  
Author(s):  
Majid Aliabadi ◽  
Abdolreza Aroujalian ◽  
Ahmadreza Raisi
Keyword(s):  
Enrichment Factor ◽  
Membrane Separation ◽  
Feed Solution ◽  
Enrichment Factors ◽  
Separation Performance ◽  
Membrane Thickness ◽  
Permeation Flux ◽  
Feed Concentration ◽  
Aqueous Streams ◽  
Successful Separation

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.

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
Keyword(s):  
Cellulose Acetate ◽  
Separation Factor ◽  
Experimental Results ◽  
Separation Performance ◽  
Permeation Flux ◽  
Feed Concentration ◽  
Blend Membrane ◽  
Pyridine Solution ◽  
Operation Temperature

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.

scholarly journals Experimental and Theoretical Analysis of Lead Pb2+ and Cd2+ Retention from a Single Salt Using a Hollow Fiber PES Membrane

Membranes ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 136
Author(s):  
Salwa Hadi ◽  
Ahmed A. Mohammed ◽  
Sama M. Al-Jubouri ◽  
Mahmood F. Abd ◽  
Hasan Shaker Majdi ◽  
...  
Keyword(s):  
Heavy Metal ◽  
Metal Concentration ◽  
Peclet Number ◽  
Film Theory ◽  
Heavy Metal Concentration ◽  
Feed Solution ◽  
Membrane Thickness ◽  
Permeation Flux ◽  
Péclet Number ◽  
Pes Membrane

The present work reports the performance of three types of polyethersulfone (PES) membrane in the removal of highly polluting and toxic lead Pb2+ and cadmium Cd2+ ions from a single salt. This study investigated the effect of operating variables, including pH, types of PES membrane, and feed concentration, on the separation process. The transport parameters and mass transfer coefficient (k) of the membranes were estimated using the combined film theory-solution-diffusion (CFSD), combined film theory-Spiegler-Kedem (CFSK), and combined film theory-finely-porous (CFFP) membrane transport models. Various parameters were used to estimate the enrichment factors, concentration polarization modulus, and Péclet number. The pH values significantly affected the permeation flux of the Pb2+ solution but only had a slight effect on the Cd2+ solution. However, Cd2+ rejection was highly improved by increasing the pH value. The rejection of the PES membranes increased greatly as the heavy metal concentration rose, while the heavy metal concentration moderately affected the permeation flux. The maximum rejection of Pb2+ in a single-salt solution was 99%, 97.5%, and 98% for a feed solution containing 10 mg Pb/L at pH 6, 6.2, and 5.7, for PES1, PES2, and PES3, respectively. The maximum rejection of Cd2+ in single-salt solutions was 78%, 50.2%, and 44% for a feed solution containing 10 mg Cd/L at pH 6.5, 6.2, and 6.5, for PES1, PES2, and PES3, respectively. The analysis of the experimental data using the CFSD, CFSK, and CFFP models showed a good agreement between the theoretical and experimental results. The effective membrane thickness and active skin layer thickness were evaluated using the CFFP model, indicating that the Péclet number is important for determining the mechanism of separation by diffusion.

Separation of Methanol/Water Mixtures from Dilute Aqueous Solutions Using Pervaporation Technique

2012 ◽  
Vol 550-553 ◽  
pp. 3004-3007 ◽  
Author(s):  
Verawat Champreda ◽  
David Stuckey ◽  
Apichat Boontawan
Keyword(s):  
Experimental Data ◽  
Flow Rate ◽  
Operating Temperature ◽  
Separation Performance ◽  
Permeation Flux ◽  
Feed Flow Rate ◽  
Feed Concentration ◽  
Dilute Aqueous Solutions ◽  
Factor Α ◽  
Feed Temperature

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%.

scholarly journals Cosolvent-Driven Interfacial Polymerization for Superior Separation Performance of Polyurea-Based Pervaporation Membrane

Polymers ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1179
Author(s):  
Manuel Reyes De Guzman ◽  
Micah Belle Marie Yap Ang ◽  
Shu-Hsien Huang ◽  
Fang-Chi Hu ◽  
Yu-Hsuan Chiao ◽  
...  
Keyword(s):  
Interfacial Polymerization ◽  
Water Concentration ◽  
Feed Solution ◽  
Attenuated Total Reflection ◽  
Water Soluble ◽  
Curing Temperature ◽  
Membrane Properties ◽  
Separation Performance ◽  
Permeation Flux ◽  
Water Contact

A thin-film composite (TFC) polyurea membrane was fabricated for the dehydration of an aqueous tetrahydrofuran (THF) solution through interfacial polymerization, wherein polyethyleneimine (a water-soluble amine monomer) and m-xylene diisocyanate (an oil-soluble diisocyanate monomer) were reacted on the surface of a modified polyacrylonitrile (mPAN) substrate. Cosolvents were used to tailor the membrane properties and increase the membrane permeation flux. Four types of alcohols that differed in the number of carbon (methanol, ethanol, isopropanol, and tert-butanol) were added as cosolvents, serving as swelling agents, to the aqueous-phase monomer solution, and their effect on the membrane properties and pervaporation separation was discussed. Attenuated total reflection Fourier transform infrared spectroscopy confirmed the formation of a polyurea layer on mPAN. Field emission scanning electron microscopy and surface water contact angle analysis indicated no change in the membrane morphology and hydrophilicity, respectively, despite the addition of cosolvents for interfacial polymerization. The TFC membrane produced when ethanol was the cosolvent exhibited the highest separation performance (permeation flux = 1006 ± 103 g·m−2·h−1; water concentration in permeate = 98.8 ± 0.3 wt.%) for an aqueous feed solution containing 90 wt.% THF at 25 °C. During the membrane formation, ethanol caused the polyurea layer to loosen and to acquire a certain degree of cross-linking. The optimal fabrication conditions were as follows: 10 wt.% ethanol as cosolvent; membrane curing temperature = 50 °C; membrane curing time = 30 min.

scholarly journals Effects of Operating Parameters on Ionic Liquid Membrane to Remove Humidity in a Green Continuous Process

Membranes ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 65
Author(s):  
Xueru Yan ◽  
Alexandre Favard ◽  
Stéphane Anguille ◽  
Marc Bendahan ◽  
Philippe Moulin
Keyword(s):  
Ionic Liquid ◽  
Flow Rate ◽  
Continuous Process ◽  
Hybrid Process ◽  
Absolute Pressure ◽  
Mechanical Resistance ◽  
Operating Parameters ◽  
Separation Performance ◽  
Feed Concentration ◽  
Time Operation

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.

Characterization of Fouled Flat Sheet Membranes by Infrared Thermography

2014 ◽  
Author(s):  
Kennethrex O. Ndukaife ◽  
George Agbai Nnanna
Keyword(s):  
Surface Temperature ◽  
Infrared Thermography ◽  
Spectral Power ◽  
Membrane Surface ◽  
Infrared Camera ◽  
Feed Solution ◽  
Feed Concentration ◽  
Ir Camera ◽  
Measure Surface Temperature

An Infrared thermography (IRT) technique for characterization of fouling on membrane surface has been developed. The emitted spectral power from the fouled membrane is a function of emissivity and surface morphology. In this work, a FLIR A320 IR camera was used to measure surface temperature and emissivity. The surface temperature and the corresponding emissivity value of various areas on the fouled membrane surface is measured by the infrared camera and recorded alongside its thermogram. Different fouling experiments were performed using different concentrations of aluminum oxide nanoparticle mixed with deionized water as feed solution (333 ppm, 1833 ppm and 3333 ppm) so as to investigate the effect of feed concentration on the degree of fouling and thus its effect on the emissivity values measured on the membrane surfaces. Surface plots in 3D and Line plots are obtained for the measured emissivity values and thickness of the fouling deposit on the membrane surface respectively. The results indicate that the IRT technique is sensitive to changes that occur on the membrane surface due to deposition of contaminants on the membrane surface and that emissivity is a function of temperature, surface roughness and thickness of the specimen under investigation.

Distribution characteristics and source analysis of metal elements in indoor PM2.5 in high-rise buildings during heating season in Northeast China

2019 ◽  
Vol 29 (8) ◽  
pp. 1087-1100 ◽  
Author(s):  
Li Bai ◽  
Zijian He ◽  
Wanyue Chen ◽  
Yujie Wang
Keyword(s):  
Principal Component Analysis ◽  
Particulate Matter ◽  
Enrichment Factor ◽  
Northeast China ◽  
Principal Component ◽  
Component Analysis ◽  
Enrichment Factors ◽  
Heating Season ◽  
Metal Elements ◽  
High Rise

This study aims to investigate whether sources of metal elements in fine particulate matter and their distribution in high-rise buildings vary with floor levels. Inductively coupled plasma emission spectrometry (ICP-AES) was used to determine the contents of 11 common heavy metals in PM2.5 samples collected from different floors of a high-rise residential building in Northeast China during the heating season. The sources of metal elements in PM2.5 samples on different floors were analysed by the enrichment factor method and the principal component analysis method. The concentration of metal elements is higher in lower floors (<7th floor) and lower in higher floors (>7th floor). The enrichment factor method shows that the enrichment factors of As, Cd, Cu and Pb may be seriously affected by human sources, while the enrichment factors of the other seven metals are less than 10, indicating that their sources may be natural sources. The principal component analysis shows that the main sources of indoor metal elements in high-rise residential buildings are divided into four main components, including coal combustion (31.44%), automobile emissions and transportation (21.60%), soil dust, particulate matter discharged from agricultural production and atmospheric dust (13.43%), metallurgical, chemical and ore mining (12.61%).

scholarly journals A Comprehensive Membrane Process for Preparing Lithium Carbonate from High Mg/Li Brine

Membranes ◽  
2020 ◽  
Vol 10 (12) ◽  
pp. 371
Author(s):  
Wenhua Xu ◽  
Dongfu Liu ◽  
Lihua He ◽  
Zhongwei Zhao
Keyword(s):  
Reverse Osmosis ◽  
Membrane Separation ◽  
Lithium Carbonate ◽  
High Mass ◽  
Separation Performance ◽  
Mass Ratio ◽  
Total Recovery ◽  
Industrial Grade ◽  
Electrochemical Intercalation ◽  
New Perspective

The preparation of Li2CO3 from brine with a high mass ratio of Mg/Li is a worldwide technology problem. Membrane separation is considered as a green and efficient method. In this paper, a comprehensive Li2CO3 preparation process, which involves electrochemical intercalation-deintercalation, nanofiltration, reverse osmosis, evaporation, and precipitation, was constructed. Concretely, the electrochemical intercalation-deintercalation method shows excellent separation performance of lithium and magnesium, and the mass ratio of Mg/Li decreased from the initial 58.5 in the brine to 0.93 in the obtained lithium-containing anolyte. Subsequently, the purification and concentration are performed based on nanofiltration and reverse osmosis technologies, which remove mass magnesium and enrich lithium, respectively. After further evaporation and purification, industrial-grade Li2CO3 can be prepared directly. The direct recovery of lithium from the high Mg/Li brine to the production of Li2CO3 can reach 68.7%, considering that most of the solutions are cycled in the system, the total recovery of lithium will be greater than 85%. In general, this new integrated lithium extraction system provides a new perspective for preparing lithium carbonate from high Mg/Li brine.

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