scholarly journals Preparation of ECTFE Porous Membrane for Dehumidification of Gaseous Streams through Membrane Condenser

Membranes ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 65
Author(s):  
Jun Pan ◽  
Kun Chen ◽  
Zhaoliang Cui ◽  
Omar Bamaga ◽  
Mohammed Albeirutty ◽  
...  
Keyword(s):  
Porous Membrane ◽  
Membrane Distillation ◽  
Membrane Properties ◽  
Attractive Potential ◽  
Water Yield ◽  
Water Recovery ◽  
Sem Images ◽  
Thermally Induced ◽  
Surface Contact Angle ◽  
Poly Ethylene

Due to the good hydrophobicity and chemical resistance of poly(ethylene trifluoroethylene) (ECTFE), it has been an attractive potential material for microfiltration, membrane distillation and more. However, few porous hydrophobic ECTFE membranes were prepared by thermally induced phase separation (TIPS) for membrane condenser applications. In this work, the diluent, di-n-octyl phthalate (DnOP), was selected to prepare the dope solutions. The calculated Hassen solubility parameter indicated that ECTFE has good compatibility with DnOP. The corresponding thermodynamic phase diagram was established, and it has been mutually verified with the bi-continuous structure observed in the SEM images. At 30 wt% ECTFE, the surface contact angle and liquid entry pressure reach their maximum values of 139.5° and 0.71 MPa, respectively. In addition, some other basic membrane properties, such as pore size, porosity, and mechanical properties, were determined. Finally, the prepared ECTFE membranes were tested using a homemade membrane condenser setup. When the polymer content is 30 wt%, the corresponding results are better; the water recovery and condensed water yield is 17.6% and 1.86 kg m−2 h−1, respectively.

Structure and Performance of PP Porous Membrane Prepared with Adipic Acid and NA-40 as Nucleating Agent via TIPS

2016 ◽  
Vol 848 ◽  
pp. 733-737
Author(s):  
Hui Xia Xuan ◽  
Chun Ju He
Keyword(s):  
Adipic Acid ◽  
Water Flux ◽  
Nucleating Agent ◽  
Porous Membrane ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Sem Images ◽  
Thermally Induced ◽  
Cooling Temperature ◽  
And Performance

Polypropylene (PP) membranes were respectively prepared using adipic acid (APA) and Sorbitol (NA-40) as nucleating agent via thermally induced phase separation (TIPS) method. The effects of nucleating agent content and cooling temperature on the structure and performance of membrane were investigated using scanning electron microscopy (SEM), wide angle X-ray diffraction (WAXD) and differential scanning calorimetry (DSC). WAXD spectrogram indicates that three kinds of α, β and γ-form crystal were formed in this preparation process and the relative content of β-form crystal in membrane prepared by NA-40 system is higher than that of membrane formed by adipic acid. SEM images show that porous structure and cellular structure were observed on the surface and cross-section of membrane. The water flux, tensile strength and elongation increase with the addition of nucleating agent content and decrease with cooling temperature rising. This paper aims to choose proper nucleating agent NA-40 and coagulation temperature to improve the properties of PP membranes.

ECTFE porous membranes with conveniently controlled microstructures for vacuum membrane distillation

2015 ◽  
Vol 3 (46) ◽  
pp. 23549-23559 ◽  
Author(s):  
Jian Pan ◽  
Changfa Xiao ◽  
Qinglin Huang ◽  
Hailiang Liu ◽  
John Hu
Keyword(s):  
Phase Separation ◽  
Membrane Distillation ◽  
Diethyl Phthalate ◽  
Porous Membranes ◽  
Microporous Membranes ◽  
Thermally Induced Phase Separation ◽  
Thermally Induced ◽  
Vacuum Membrane Distillation ◽  
Poly Ethylene

Poly(ethylene chlorotrifluoroethylene) (ECTFE) microporous membranes were prepared via a thermally induced phase separation (TIPS) process using a mixed diluent of bis(2-ethylhexyl) adipate (DEHA) and diethyl phthalate (DEP).

scholarly journals Recent Progress in the Membrane Distillation and Impact of Track-Etched Membranes

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2520
Author(s):  
Arman B. Yeszhanov ◽  
Ilya V. Korolkov ◽  
Saule S. Dosmagambetova ◽  
Maxim V. Zdorovets ◽  
Olgun Güven
Keyword(s):  
Water Purification ◽  
Vinylidene Fluoride ◽  
Liquid Radioactive Waste ◽  
Theoretical Models ◽  
Membrane Distillation ◽  
Narrow Pore Size Distribution ◽  
Poly Ethylene Terephthalate ◽  
Poly Vinylidene Fluoride ◽  
Poly Ethylene ◽  
Purification Of Water

Membrane distillation (MD) is a rapidly developing field of research and finds applications in desalination of water, purification from nonvolatile substances, and concentration of various solutions. This review presents data from recent studies on the MD process, MD configuration, the type of membranes and membrane hydrophobization. Particular importance has been placed on the methods of hydrophobization and the use of track-etched membranes (TeMs) in the MD process. Hydrophobic TeMs based on poly(ethylene terephthalate) (PET), poly(vinylidene fluoride) (PVDF) and polycarbonate (PC) have been applied in the purification of water from salts and pesticides, as well as in the concentration of low-level liquid radioactive waste (LLLRW). Such membranes are characterized by a narrow pore size distribution, precise values of the number of pores per unit area and narrow thickness. These properties of membranes allow them to be used for more accurate water purification and as model membranes used to test theoretical models (for instance LEP prediction).

scholarly journals Poly(δ-valerolactone)/Poly(ethylene-co-vinylalcohol)/β-Tricalcium Phosphate Composite as Scaffolds: Preparation, Properties, and In Vitro Amoxicillin Release

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 46
Author(s):  
Mohammed Badwelan ◽  
Mohammed Alkindi ◽  
Osama Alghamdi ◽  
Waseem Sharaf Saeed ◽  
Abdel-Basit Al-Odayni ◽  
...  
Keyword(s):  
Hybrid Materials ◽  
Tricalcium Phosphate ◽  
Drug Carrier ◽  
Human Mesenchymal Stem Cells ◽  
In Vitro Study ◽  
Micro Computed Tomography ◽  
Scanning Calorimetry ◽  
Sem Images ◽  
Poly Ethylene

Two poly(δ-valerolactone)/poly(ethylene-co-vinylalcohol)/β-tricalcium phosphate (PEVAL/PDVAL/β-TCP) composites containing an equal ratio of polymer and filled with 50 and 70 wt% of β-TCP microparticles were prepared by the solvent casting method. Interconnected pores were realized using the salt leached technique, and the porosity of the resulted composites was evaluated by the scanning electron microscopy (SEM) method. The homogeneity of the hybrid materials was investigated by differential scanning calorimetry (DSC) and X-ray diffraction (XRD) analysis. The prepared materials’ SEM images showed interconnected micropores that respond to the conditions required to allow their uses as scaffolds. The porosity of each scaffold was determined from micro computed tomography (micro-CT) data, and the analysis of the mechanical properties of the prepared materials was studied through the stress-strain compressive test. The proliferation test results used human mesenchymal stem cells (MSCs) to grow and proliferate on the different types of prepared materials, reflecting that the hybrid materials were non-toxic and could be biologically acceptable scaffolds. The antibacterial activity test revealed that incorporation of amoxicillin in the specimens could inhibit the bacterial growth of S. aureus. The in vitro study of the release of amoxicillin from the PEVAL/PDVAL/amoxicillin and PEVAL/PDVAL/β-TCP/amoxicillin drug carrier systems in pH media 7.4, during eight days, gave promising results, and the antibiotic diffusion in these scaffolds obeys the Fickian model.

scholarly journals Capillary Polypropylene Membranes for Membrane Distillation

Fibers ◽  
2018 ◽  
Vol 7 (1) ◽  
pp. 1 ◽  
Author(s):  
Marek Gryta
Keyword(s):  
Continuous Process ◽  
Negative Influence ◽  
Membrane Distillation ◽  
Water Desalination ◽  
Porous Membranes ◽  
Surface Porosity ◽  
Permeate Flux ◽  
Thermally Induced

Only nonwetted porous membranes can be used in membrane distillation. The possibility of application in this process the capillary polypropylene membranes manufactured by thermally-induced phase separation was studied. The performance of a few types of membranes available commercially was presented. The resistance of the membranes to wetting was tested in the continuous process of water desalination. These studies were carried out for 1000 h without module cleaning. The presence of scaling layer on the membranes surface was confirmed by Scanning Electron Microscope observations. Both the permeate flux and distillate conductivity were almost not varied after the studied period of time, what indicates that the used membranes maintained their nonwettability, and the negative influence of scaling was limited. The role of surface porosity on the pore wetting and influence of membrane wettability on the quality of the distillate obtained were discussed.

scholarly journals Exploiting the Interplay between Liquid-Liquid Demixing and Crystallization of the PVDF Membrane for Membrane Distillation

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
N. I. M. Nawi ◽  
M. R. Bilad ◽  
N. A. H. M. Nordin ◽  
M. O. Mavukkandy ◽  
Z. A. Putra ◽  
...  
Keyword(s):  
Polyvinylidene Fluoride ◽  
Water Flux ◽  
High Water ◽  
Membrane Distillation ◽  
Degree Of Crystallinity ◽  
Solution Temperature ◽  
Hydrophobic Membrane ◽  
Sem Images ◽  
Cold Temperatures ◽  
Dope Solution

Membrane distillation (MD) purifies water by transporting its vapor through a hydrophobic membrane. An ideal MD membrane poses high water flux and high fouling, scaling, and wetting resistances. In this study, we develop polyvinylidene fluoride (PVDF) membranes for MD by focusing on reduction of PVDF degree of crystallinity. We explore the roles of dope solution temperature in dictating the phase separation mechanisms as well as the structure and the performance of semicrystalline PVDF membranes. DSC spectra show that higher dope solution temperature depresses crystallinity via formation of imperfect crystal. Such findings were also supported by FTIR and XRD results. The SEM images reveal formation of spherulite-like morphology in the membrane matrices for membranes prepared from high temperature dope solutions. A good balance between solid-liquid and liquid-liquid phase separations that offers low degree of crystallinity was found at a dope solution temperature of 60°C (PVDF-60), which showed the MD flux of 18 l/m2 h (vs. 6 l/m2 h for temperature of 25°C, as a benchmark) and nearly complete salt rejection when run at hot and cold temperatures of 65°C and 25°C, respectively. The PVDF-60 shows a high wetting resistance and stable MD flux of 10.5 l/m2 h over a 50 h test for treating brine solution as the feed (70 g NaCl/l).

scholarly journals Separation and Recycling of Concentrated Heavy Metal Wastewater by Tube Membrane Distillation Integrated with Crystallization

Membranes ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 19 ◽  
Author(s):  
Xiang-Yang Lou ◽  
Zheng Xu ◽  
An-Ping Bai ◽  
Montserrat Resina-Gallego ◽  
Zhong-Guang Ji
Keyword(s):  
Heavy Metal ◽  
Membrane Fouling ◽  
Pure Water ◽  
Sharp Decrease ◽  
Membrane Distillation ◽  
Water Yield ◽  
Mixed System ◽  
Mixed Solutions ◽  
Membrane Flux ◽  
Salt Crystals

Tube membrane distillation (MD) integrated with a crystallization method is used in this study for the concurrent productions of pure water and salt crystals from concentrated single and mixed system solutions. The effects of concentrated Zn2+ and Ni2+ on performance in terms of membrane flux, permeate conductivity, crystal recovery rates, and crystal grades are investigated. Preferred crystallization and co-crystallization determinations were performed for mixed solutions. The results revealed that membrane fluxes remained at 2.61 kg·m−2·h−1 and showed a sharp decline until the saturation increased to 1.38. Water yield conductivity was below 10 μs·cm−1. High concentrated zinc and nickel did not have a particular effect on the rejection of the membrane process. For the mixed solutions, membrane flux showed a sharp decrease due to the high saturation, while the conductivity of permeate remained below 10 μs·cm−1 during the whole process. Co-crystallization has been proven to be a better method due to the existence of the SO42− common-ion effect. Membrane fouling studies have suggested that the membrane has excellent resistance to fouling from highly concentrated solutions. The MD integrated with crystallization proves to be a promising technology for treating highly concentrated heavy metal solutions.

scholarly journals EVALUATION OF BACTERIAL CELLULOSE-SODIUM ALGINATE FORWARD OSMOSIS MEMBRANE FOR WATER RECOVERY

2018 ◽  
Vol 80 (3-2) ◽  
Author(s):  
Ngan T. B. Dang ◽  
Liza B. Patacsil ◽  
Aileen H. Orbecido ◽  
Ramon Christian P. Eusebio ◽  
Arnel B. Beltran
Keyword(s):  
Contact Angle ◽  
Bacterial Cellulose ◽  
Sodium Alginate ◽  
Water Flux ◽  
Forward Osmosis ◽  
Composite Membranes ◽  
Membrane Thickness ◽  
Water Recovery ◽  
Sem Images ◽  
Salt Rejection

Water resources are very important to sustain life. However, these resources have been subjected to stress due to population growth, economic and industrial growth, pollution and climate change. With these, the recovery of water from sources such as wastewater, dirty water, floodwater and seawater is a sustainable alternative. The potential of recovering water from these sources could be done by utilizing forward osmosis, a membrane process that exploits the natural osmotic pressure gradient between solutions which requires low energy operation. This study evaluated the potential of forward osmosis (FO) composite membranes fabricated from bacterial cellulose (BC) and modified with sodium alginate. The membranes were evaluated for water flux and salt rejection. The effect of alginate concentrations and impregnation temperatures were evaluated using 0.6 M sodium chloride solution as feed and 2 M glucose solution as the draw solution. The membranes were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Contact Angle Meter (CAM). The use of sodium alginate in BC membrane showed a thicker membrane (38.3 μm to 67.6 μm), denser structure (shown in the SEM images), and more hydrophilic (contact angle ranges from 28.39° to 32.97°) compared to the pristine BC membrane (thickness = 12.8 μm and contact angle = 66.13°). Furthermore, the alginate modification lowered the water flux of the BC membrane from 9.283 L/m2-h (LMH) to value ranging from 2.314 to 4.797 LMH but the improvement in salt rejection was prominent (up to 98.57%).

scholarly journals Water Triggered Shape Memory Materials

2013 ◽  
Vol 3 (1) ◽  
pp. 49-50 ◽  
Author(s):  
Guoguang Niu
Keyword(s):  
Shape Memory ◽  
Shape Recovery ◽  
Shape Memory Polymers ◽  
Electrical Current ◽  
Light Illumination ◽  
Poly Ethylene Glycol ◽  
Thermally Induced ◽  
Permanent Shape ◽  
Poly Ethylene ◽  
Novel Strategy

The term "shape memory effect" refers to the ability of a material to be deformed and fixed into a temporary shape, and to recover its original, permanent shape upon an external stimulus (1). Shape memory polymers have attracted much interest because of their unique properties, and applied tremendously in medical area, such as biodegradable sutures, actuators, catheters and smart stents (2, 3). Shape memory usually is a thermally induced process, although it can be activated by light illumination, electrical current, magnetic, or electromagnetic field (4-6). During the process, the materials are heated directly or indirectly above their glass transition temperature (Tg) or the melting temperature (Tm) in order to recover the original shape. Non-thermally induced shape memory polymers eliminate the temperature constrains and enable the manipulation of the shape recovered under ambient temperature (7, 8). Herein, we report a novel strategy of water induced shape memory, in which the formation and dissolution of poly(ethylene glycol) (PEG) crystal is utilized for the fixation and recovery of temporary deformation of hydrophilic polymer. This water-induced shape recovery is less sensitive to temperature, of which 95% deformation is fixed in circumstance and over 75% recovery is reached even at 0 oC.

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