Applications and characterization of silicalite-1/polydimethylsiloxane composite membranes for the pervaporation of a model solution and fermentation broth

2019 ◽  
Vol 39 (2) ◽  
pp. 152-160
Author(s):  
Sutida Marthosa ◽  
Wirote Youravong ◽  
Chaiwat Kongmanklang ◽  
Watsa Khongnakorn
Keyword(s):  
Separation Factor ◽  
Membrane Separation ◽  
Fermentation Broth ◽  
Composite Membranes ◽  
Decomposition Temperature ◽  
Ethanol Solution ◽  
Pdms Membrane ◽  
Separation Performance ◽  
Gravimetric Analysis ◽  
Initial Decomposition Temperature

AbstractEthanol recovery via pervaporation is greatly influenced by membrane separation performance, which can be enhanced by adding hydrophobic fillers such as silicalite-1. Silicalite-1 was prepared by controlling the gel molar composition in hydrothermal synthesis, and it was incorporated into a polydimethylsiloxane (PDMS) membrane on Teflon. The silicalite-1 Si-O-Si structures interacted with the -Si(CH3)2-O- backbone of the PDMS chain. The thermal gravimetric analysis results showed that the silicalite-1 improved the thermal stability and raised the initial decomposition temperature from 405°C to 450–470°C. Increasing silicalite-1 content from 5 to 20 wt% enhanced the relative ethanol/water swelling from 1.33% to 1.52% and advanced the contact angle from 112.6° to 138.6°. Addition of 20 wt% silicalite-1 improved the separation factor in broth from 2.55 to 5.56. When using 20 wt% silicalite-1/PDMS membrane and replacing the ethanol solution with broth, fouling reduced the flux from 597 to 482 g m−2h−1, but the broth composite increased the separation factor from 3.14 to 5.56. The overall pervaporation separation index with a santol broth of the 20 wt% silicalite-1/PDMS and commercial PDMS membranes were 2199 and 2110. The prepared membranes had similar overall performance as a commercial membrane.

High Performance Poly (Vinyl Alcohol)-Zeolite LTA Composite Membranes for Ethanol Dehydration Pervaporation

2011 ◽  
Vol 287-290 ◽  
pp. 2053-2056
Author(s):  
Zhen Huang ◽  
Wei Juan Jiang ◽  
Xiao Han Shi ◽  
Li Jun Teng
Keyword(s):  
Separation Factor ◽  
Vinyl Alcohol ◽  
High Performance ◽  
Composite Membranes ◽  
Ethanol Solution ◽  
Poly Vinyl Alcohol ◽  
Processing Temperature ◽  
Ethanol Dehydration ◽  
Zeolite Lta ◽  
Separation Performances

Three-layered zeolite LTA-filled poly (vinyl alcohol) (PVA) composite membranes have been fabricated for water removal from highly concentrated ethanol solution by means of pervaporation. Higher separation factor and higher fluxes are both achieved after adding zeolite 3A, 4A and 5A. Through evaluating separation factor and permeation flux, separation performances of the composite membranes are elucidated in terms of the zeolite pore size and processing temperature.

Toughness and Thermal Properties of MWCNTs/EP Composites

2013 ◽  
Vol 763 ◽  
pp. 130-134
Author(s):  
Xiao Zhi Ding ◽  
Xia Wang ◽  
Wei Chain ◽  
Xiao Yan Li
Keyword(s):  
Thermal Properties ◽  
Fracture Energy ◽  
Decomposition Temperature ◽  
Gravimetric Analysis ◽  
Initial Decomposition Temperature ◽  
Limiting Oxygen Index ◽  
Ep Matrix ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes ◽  
Hot Melt

Multi-walled carbon nanotubes (MWCNTs) were incorporated into epoxy resin (EP) to improve the resins toughness and thermal properties. MWCNTs/EP composites were prepared by hot melt method. The fracture energy of composites was determined by wedge test, measure length of crack extension of the composites, and calculates the fracture energy. Results show improved composites toughness, as MWCNTs were dispersed in EP matrix evenly, thus absorbed impact energy. Thermal gravimetric analysis (TGA) results suggest that initial decomposition temperature increased by adding MWCNTs, with a promoted formation of a structural antiflaming network, which led to enhancement of thermal stability of the composites. The limiting oxygen index (LOI) and LU-94 data also showed a decrease of flammability of the composites.

scholarly journals Removal of Acetone from Wastewater by POSS Loaded PDMS Membrane

2017 ◽  
Vol 61 (3) ◽  
pp. 163 ◽  
Author(s):  
Filiz Ugur Nigiz ◽  
Nilufer Durmaz Hilmioglu
Keyword(s):  
Waste Water ◽  
Separation Factor ◽  
Water Concentration ◽  
Cost Effective ◽  
Pdms Membrane ◽  
Separation Performance ◽  
Hydrophobic Membrane ◽  
Acetone Concentration ◽  
Dimethyl Siloxane ◽  
Acetone Water

The waste-water of the chemical processes includes hundreds of hazardous pollutants with low concentration. Although the emission of trace amounts of these chemicals is allowed by the laws, they are quite harmful to the water ecosystem and the human health. These chemicals including the acetone, toluene, phenol, and esters are defined as volatile organic compounds (VOCs). Separation of the VOCs from the large volume of industrial waste-water is required practically complicated and advanced processes. In this approach, more economically and efficient separation methods can be more favorable such as pervaporation. Pervaporation (PV) is an attractive and promising method for separation the small amount of dissolved chemicals from the waste-water. Pervaporative separation does not need any toxic solvent or external heat energy during the separation process. Therefore, it is defined as a cost effective and environmentally friendly process. In this study, acetone was selected as a VOC component and it was selectively separated from the model mixture (acetone-water) by pervaporation where the poly(hedral oligomeric silsesquioxane)(POSS) loaded poly(dimethyl siloxane) hydrophobic membrane was used. The structure of the membrane was characterized by scanning electron and polarized microscopy methods. The surface structure of the membrane was also analyzed by contact angle measurements. Effects of feed temperature and acetone-water concentration on separation performance were evaluated in terms of the total flux and acetone separation factor. Compared to the pristine PDMS membrane, 212% improvement on separation factor was achieved by 10 wt.% POSS incorporated membrane. The highest acetone separation factor was obtained as 237 when the temperature was 30 ºC and the acetone concentration was 1%.

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.

Pervaporation Dehydration of Aqueous Ethanol Solution with Zeolite-Filled Poly (vinyl Alcohol) Composite Membranes

2011 ◽  
Vol 239-242 ◽  
pp. 1331-1334
Author(s):  
Zhen Huang ◽  
Yu Hua Guo ◽  
Gui Mei Guo ◽  
Li Jun Teng
Keyword(s):  
Separation Factor ◽  
Vinyl Alcohol ◽  
Composite Membranes ◽  
Ethanol Solution ◽  
Poly Vinyl Alcohol ◽  
Water Separation ◽  
Neat Polymer ◽  
Hydrophobic Nature ◽  
Separation Performances ◽  
High Separation

Pervaporation performances of three –layer zeolite-filled poly (vinyl alcohol) composite membranes have been investigated for ethanol dehydration. Compared the neat polymer counterparts, high separation factor and high fluxes are both achieved by these membranes, indicating that ethanol/water separation is enhanced with the zeolites. Zeolites used include 3A, 4A, 5A, NaX, NaY, silicalite-1 and Beta. Through evaluating separation factor, ethanol flux and total pervaporation flux, separation performances of composite membranes are elucidated in detail in terms of the zeolite pore size, its hydrophilic/hydrophobic nature as well as its crystal framework.

Hydrophilic porous polyimide/β-cyclodextrin composite membranes with enhanced gas separation performance and low dielectric constant

2017 ◽  
Vol 30 (4) ◽  
pp. 446-455 ◽  
Author(s):  
Zehan Liu ◽  
Long Pang ◽  
Qing Li ◽  
Shulai Zhang ◽  
Jing Li ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Contact Angle ◽  
Gas Adsorption ◽  
Composite Films ◽  
Tensile Modulus ◽  
Composite Membranes ◽  
Separation Performance ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Good Thermal Stability

A series of co-polyimide (PI)/modified β-cyclodextrin (β-CD) composites were successfully fabricated from anhydride-terminated PI and (3-aminopropyl)triethoxysilane-modified β-CD (β-ACD). Co-PI was prepared from 4,4′-oxydianiline, 4,4′-(hexafluoroisopropylidene) diphthalic anhydride, and 2,2-bis[4-(3,4-dicarboxyphenoxy)phenyl]propane dianhydride by chemical imidization. Different amounts of β-ACD (0, 1, 3, 5, and 7 wt%) were introduced into co-PI via strong covalent interactions between the terminal anhydride and amino groups. The structures and properties of the composites were characterized by means of Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, thermal gravimetric analysis, differential scanning calorimetry, dynamic thermomechanical analysis, mechanical properties tests, and contact angle tests. The results showed that β-ACD was successfully grafted on the PI segment. The composite films showed good thermal stability, glass transition temperatures between 244°C and 254°C, and 10% weight loss at temperatures of 514°C–545°C and 506°C–538°C in nitrogen and air atmosphere, respectively. They also exhibited excellent mechanical properties with tensile strength, tensile modulus, and elongation at break values of 78–111 MPa, 1.14–2.05 GPa, and 8–17%, respectively. All of these values were maximized at a β-ACD content of 1 wt%. The water uptake of the composites films was more than 1%, indicating that the addition of β-ACD can enhance the water absorption of PI films. All of these composite films are porous, and the contact angle indicated that the addition of β-ACD increased the hydrophilicity of the composite film. When the β-ACD doping content reached 7 wt%, the contact angle reached a minimum of 63°. All of the membranes were thermally annealed at 300°C for 1 h, after which gas adsorption tests showed that the composite films have enhanced CO2/CH4 selectivity, which can reach 12.7 (308 K).

scholarly journals Biocomposites of Bio-Polyethylene Reinforced with a Hydrothermal-Alkaline Sugarcane Bagasse Pulp and Coupled with a Bio-Based Compatibilizer

Molecules ◽  
2020 ◽  
Vol 25 (9) ◽  
pp. 2158
Author(s):  
Nanci Vanesa Ehman ◽  
Diana Ita-Nagy ◽  
Fernando Esteban Felissia ◽  
María Evangelina Vallejos ◽  
Isabel Quispe ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
3D Printing ◽  
Water Absorption ◽  
Sugarcane Bagasse ◽  
Thermo Gravimetric Analysis ◽  
Decomposition Temperature ◽  
Gravimetric Analysis ◽  
Scanning Calorimetry ◽  
Cradle To Gate ◽  
Bagasse Pulp

Bio-polyethylene (BioPE, derived from sugarcane), sugarcane bagasse pulp, and two compatibilizers (fossil and bio-based), were used to manufacture biocomposite filaments for 3D printing. Biocomposite filaments were manufactured and characterized in detail, including measurement of water absorption, mechanical properties, thermal stability and decomposition temperature (thermo-gravimetric analysis (TGA)). Differential scanning calorimetry (DSC) was performed to measure the glass transition temperature (Tg). Scanning electron microscopy (SEM) was applied to assess the fracture area of the filaments after mechanical testing. Increases of up to 10% in water absorption were measured for the samples with 40 wt% fibers and the fossil compatibilizer. The mechanical properties were improved by increasing the fraction of bagasse fibers from 0% to 20% and 40%. The suitability of the biocomposite filaments was tested for 3D printing, and some shapes were printed as demonstrators. Importantly, in a cradle-to-gate life cycle analysis of the biocomposites, we demonstrated that replacing fossil compatibilizer with a bio-based compatibilizer contributes to a reduction in CO2-eq emissions, and an increase in CO2 capture, achieving a CO2-eq storage of 2.12 kg CO2 eq/kg for the biocomposite containing 40% bagasse fibers and 6% bio-based compatibilizer.

Polyvinylamine/graphene oxide/PANI@CNTs mixed matrix composite membranes with enhanced CO2/N2 separation performance

2019 ◽  
Vol 589 ◽  
pp. 117246 ◽  
Author(s):  
Yonghong Wang ◽  
Long Li ◽  
Xinru Zhang ◽  
Jinping Li ◽  
Chengcen Liu ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Matrix Composite ◽  
Composite Membranes ◽  
Separation Performance ◽  
Mixed Matrix

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

Study on Synthesis and Thermal Property of Polyvinylamine

2010 ◽  
Vol 150-151 ◽  
pp. 1500-1503 ◽  
Author(s):  
Hong Chi Zhao ◽  
Qi Li ◽  
Wen Yu Xu ◽  
Fan Huang
Keyword(s):  
Decomposition Temperature ◽  
Characteristic Peak ◽  
Initial Decomposition Temperature ◽  
Nmr Spectrum ◽  
X Ray ◽  
Nuclear Magnetic Resonance Spectrometer ◽  
Chemical Structures ◽  
Thermogravimetric Analyzer ◽  
Infrared Spectrometer ◽  
Thermal Stability Of

Polyvinylamine (PVAm) and polyvinylamine chloride (PVAm•HCl) were synthesized by Hofmann degradation of polyacrylamide (PAM). The reaction condition is gentle and the operation is safe, simple and economical so that it is a good reaction method. The chemical structures and thermal properties of the polymers were studied by Fourier transform infrared spectrometer (FTIR), nuclear magnetic resonance spectrometer (NMR), X-ray diffractmeter (XRD) and thermogravimetric analyzer (TGA). Synthesis of PVAm•HCl was confirmed by the intensities of the characteristic peak of -CONH2 decreased and the appearance of a new absorption peak at 1530cm-1 (due to N-H bond of -NH3+ ) in the FTIR spectrum, the appearance of the characteristic absorption peaks of carbon atoms in the 13C NMR spectrum, the appearance of chemical shift assignments of proton in 1H NMR spectrum and the appearance of characteristic dispersing diffraction peak between 22.5° to 25.2° in the XRD spectrum, respectively. PAM had three decomposing stages, but PVAm•HCl had two decomposing stages. TG curve of PAM and PVAm•HCl showed that the initial decomposition temperature were 190oC and 140oC, respectively. The thermal stability of PVAm•HCl was poorer than that of PAM.

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