Thin film composite membrane

Top PDF Thin film composite membrane:

Preparation of Poly(ether-6-block amide)/PVC Thin Film Composite Membrane for CO2 Separation: Effect of Top Layer Thickness and Operating Parameters

Preparation of Poly(ether-6-block amide)/PVC Thin Film Composite Membrane for CO2 Separation: Effect of Top Layer Thickness and Operating Parameters

SEM was applied to examine the morphology of surface and cross- sectional of the fabricated thin film composite membrane. The membrane sample was fractured in liquid nitrogen, sputter-coated with gold by a BAL- TEC SCD 005 sputter coater (BAL-TEC AG, Balzers, Liechtenstein) and tested with a KYKY-EM3200 (KYKY Technology Development Ltd., Beijing, China) scanning electron microscope.

6 Read more

A recent progress in thin film composite membrane: A review

A recent progress in thin film composite membrane: A review

modify transport properties of RO membranes by employing different types of molecular sieve nanoparticles in PA fi lm [48,49]. Fig. 5 depicts the new concept of embedding molecular sieve nanoparticles in the top selective layer in the preparation of thin fi lm nanocomposite (TFN) membrane. The new concept was fi rst started by Hoek et al. [48] in early 2007. In their pioneering work, it is experienced that the super-hydrophilic and negatively charged zeolite-A embedded throughout PA thin fi lm was able to dramatically improve the permeability of the TFN membrane and remained equivalent salt rejection when compared with the pure PA composite membrane. Since the size of the zeolite particles is designed to match the PA fi lm thickness, it thus provides a favorable fl ow path through each particle incorporated into membrane, leading to high water permeation [49]. This improved membrane water process is just as effective as current technology but more energy ef fi cient and potentially less expensive. In order to further enhance water molecules transport rate, Fathizadeh et al. [50] in year 2011 impregnated bigger pore size of zeolite NaX (7.4 Å) in the thin fi lm layer with the aims of creating larger molecular tunnels for water to fl ow. It is found that this particular pore size of zeolite offers preferential fl ow paths for water molecules of 2.7 Å in diameter but restricts the permeation of hydrated sodium and chloride ions (8 – 9 Å). Instead of differences in particles' size, controllable design in interfacial chemistry of mem- brane is also possible using other type of molecular sieves, owing to their tunable functionality with respect to hydrophilicity, charge density and antimicrobial capability. It was recently reported by Kim and Deng [51] that hydrophilized ordered mesoporous carbons (H-OMCs) modi fi ed from pristine OMCs were possible to be used as nano- fi ller in making thin- fi lm polymer matrix of improved proper- ties. According to them, the plasma treated H-OCMs could be well dispersed in the aqueous solution which were likely to minimize large
Show more

10 Read more

Seawater Reverse Osmosis (SWRO) desalination by thin film composite membrane—Current development, challenges and future prospects

Seawater Reverse Osmosis (SWRO) desalination by thin film composite membrane—Current development, challenges and future prospects

Since the breakthrough discovery made by Cadotte and his co-workers in the 1970s, thin-film composite (TFC) membrane prepared using interfacial polymerization (IP) technique has experienced signi fi cant pro- gress in composite membrane development and emerged as one of the most advanced technologies in water and wastewater purification processes. Nowadays, the most promising technology to desalinate seawater is reverse osmosis (RO), which is driven by a pressure gradient across a semi-permeable membrane. This technology has drawn great attention mainly due to its relatively low energy usage during operation as well as easy of operation and maintenance compared to other conventional technologies such as thermal desalination. On the basis of the brief introduction on TFC membrane, this paper will highlight the recent developments of RO TFC membrane and its challenges in seawater desalination process with respect to fouling problem, boron rejection and chlorine attack. Future directions in SWRO membrane research are also discussed to further expand research and development related to seawater desalination process.
Show more

10 Read more

Plasma-induced physicochemical effects on a poly(amide) thin-film composite membrane

Plasma-induced physicochemical effects on a poly(amide) thin-film composite membrane

56. Tang, C.Y., Y.-N. Kwon, and J.O. Leckie, Effect of membrane chemistry and coating layer on physiochemical properties of thin-film composite polyamide RO and NF membranes: I. FTIR and XPS characterization of polyamide and coating layer chemistry. Desalination, 2009. 242(1–3): p. 149-167.

34 Read more

Zwitterion Embedded Thin Film Composite Membrane for Oily Wastewater Treatment

Zwitterion Embedded Thin Film Composite Membrane for Oily Wastewater Treatment

There are several readily available technologies for oily separation. Flotation is considered a simple way of removing oil from wastewater. As wastewater is poured in the form of fine bubbles, the oil particles will adhere to the tiny air bubbles and will be suspended in the water, prior to the lower density of oil particles. Then the scum layer formed will be removed from water [3]. The advantages of flotation is high processing capacity, high separation efficiency and low sludge production. However, flotation also suffers from limitations such as potential manufacturing and repairing problems, as well as high energy consumption. Coagulation is another separation technology where emulsified and dissolved oil along with some difficult biodegradable polymers can be removed. Prior to its ability to destabilize and aggregate colloids, the popular is widely used. Besides, the advantage of being able to reach very high oil removal efficiency, up to 99% with the aids of aggregation zinc silicate (PISS) and anionic polyacrylamide (A-PAM) composite flocculant also causes its popularity [4]. However, in these approaches, repeated testing must be carried out to screen and choose the suitable chemical required to treat the complex wastewater composition. Apart from that, these processes suffer from high cost and can easily cause secondary pollution of water bodies. Biological treatment utilizes microbial metabolism to treat wastewater. As the water is dissolved, organic pollutants will be changed into harmless substances and stabilized [5]. Biological treatment is commonly used in activated sludge and biological filter methods. There are several advantages of biological treatment such as eco- friendly and high thermostability. However, the process is very time-consuming, which could take up from weeks to months [6]. Most of the methods above face high energy consumption or environmental barrier with stable emulsified oil prior to the size of oil droplets which are normally less than 20 μm because of the stabilizing effect from surfactants .
Show more

9 Read more

The effect of curing temperature on the performance of thin film composite membrane

The effect of curing temperature on the performance of thin film composite membrane

Most of the research works done previously had studied the effect of curing temperature on the performances of TFC membranes with polysulfone as the porous support but using various other compositions of cross-linked material. Thus, this study investigates the possibility of using cellulose acetate as a micro porous support for the TFC membranes using new combination of cross-linked mixtures of acyl chlorides and polyamines, and compares its performance with polysulfone TFC membranes. The exact curing temperature is important for attaining the desired stability of thin composite membrane. This stability is important to give high pure water permeability, high product rate and high rejection rate. The mathematical model of membrane transport by Kimura-Sourirajan [13 ] was applied to evaluate the experimental results to predict pure water permeability constant (A), solute transport parameter (DAM/k δ) and mass transfer coefficient (k). Values of A and DAM/k δ are useful in specifying a membrane. Additionally, k value is required to make use of basic transport equations to predict the membrane performance.
Show more

13 Read more

Towards Enhanced Performance Thin-film Composite Membranes via Surface Plasma Modification

Towards Enhanced Performance Thin-film Composite Membranes via Surface Plasma Modification

Advancing the design of thin-film composite membrane surfaces is one of the most promising pathways to deal with treating varying water qualities and increase their long-term stability and permeability. Although plasma technologies have been explored for surface modification of bulk micro and ultrafiltration membrane materials, the modification of thin film composite membranes is yet to be systematically investigated. Here, the performance of commercial thin-film composite desalination membranes has been significantly enhanced by rapid and facile, low pressure, argon plasma activation. Pressure driven water desalination tests showed that at low power density, flux was improved by 22% without compromising salt rejection. Various plasma durations and excitation powers have been systematically evaluated to assess the impact of plasma glow reactions on the physico-chemical properties of these materials associated with permeability. With increasing power density, plasma treatment enhanced the hydrophilicity of the surfaces, where water contact angles decreasing by 70% were strongly correlated with increased negative charge and smooth uniform surface morphology. These results highlight a versatile chemical modification technique for post-treatment of commercial membrane products that provides uniform morphology and chemically altered surface properties.
Show more

13 Read more

Preparation of Novel Thin-Film Composite Nanofiltration Membranes for Separation of Amoxicillin

Preparation of Novel Thin-Film Composite Nanofiltration Membranes for Separation of Amoxicillin

Fig. 3 illustrates the surface and cross-section of PSf membrane support and polyamide thin-film composite membrane with and without Titania nanoparticle self-assembly on the surface. It can be observed that the top dense layer and finger-like structure are distinguishable in the cross-section of support before the formation of polyamide selective layer (Fig. 3B and C). This structure was the same as that was formed in the Loeb-Sourirajan or phase separation membranes [36]. Also, the surface morphology of PSf support was smooth and integrated (Fig 3A). In the performance of thin-film composite nanofiltration membranes, the perfect establishment of thin-film selective layer is a very important factor. As shown in Figs. 3E, F, H and I, the polyamide layer was attached completely and correctly to the top surface of support and was separately observed from finger-like layer. When the polyamide thin-film layer was formed, the membrane surface became unsmooth (Fig 3D). Furthermore, the presence of TiO 2 nanoparticles
Show more

12 Read more

Magnetic micropump embedded in contact lens for on-demand drug delivery

Magnetic micropump embedded in contact lens for on-demand drug delivery

micropump is a battery-free system and actuated by the external magnetic field whenever needed (Fig.  1a). The proposed micropump was composed of top layer for membrane transfer, functional thin PDMS membrane as a part of check valve and actuator, magnetic nanoparti- cle-PDMS composite (MNPC) for actuation under mag- netic field pulse, middle chamber for drug loading, and bottom cover including drug loading aperture. The top layer faces to the cornea and the drug can be released from the micropump to the post-lens tear film between lens and cornea. In addition, the micro check valve, which consists of elastic thin PDMS membrane and rigid thick Ostemer layer, was integrated with the micropump for one-directional drug delivery. The thin PDMS mem- brane and thick Ostemer layer has apertures with dif- ferent sizes and locations, and the deflection of the thin PDMS membrane can be controlled by magnetic field acted on the MNPC which causes the drug release from
Show more

6 Read more

Charge tunable thin-film composite membranes by gamma-ray triggered surface polymerization

Charge tunable thin-film composite membranes by gamma-ray triggered surface polymerization

positive net charge profiles across the full pH range. The isoelectric point (IEP) of the grafted membranes between the 1 and 10 kGy was shifted from approx. pH 4.5 to pH 6.8 reaching a net charge of +45 mV in the acidic pH range. In addition, the net charge profile in the alkaline pH range above pH 8, was found to reach − 5 mV, there- fore nearly 5 times higher than the reference membranes. At 100 kGy, the charge was always positive across the complete pH range, reached maximum of + 47 mV in the acid range and a minimum of + 5 mV within the alka- line range. These results are significant since they provide evidence that TFC materials may be in-depth modified to offer highly tunable surface charges and IEPs. These are, to the best of the authors’ knowledge, the largest net charge shifts ever reported for TFC PA based membranes. On the other hand, the pristine membranes exposed to a 1 v/v% of VIM concentration solution, have up-taken monomer molecules by adsorption, presented an IEP at pH 4.5 and a positive net charge increased range from pH 3 to 6. The net difference with the reference, untreated, membranes was therefore largely significant in that range. However, within the alkaline range, and particularly above pH 8, the pristine membrane exhibited a negative profile with a net charge around − 15 mV, within the same range to that of the pristine membranes, demonstrating more similarities with the reference membrane.
Show more

10 Read more

Study on the thin film composite poly(piperazine amide) nanofiltration
membrane: Impacts of physicochemical properties of substrate on
interfacial polymerization formation

Study on the thin film composite poly(piperazine amide) nanofiltration membrane: Impacts of physicochemical properties of substrate on interfacial polymerization formation

Asymmetric PSf substrate was prepared via phase inversion tech- nique using a polymer dope with a PSf concentration of 15 wt.%. In order to increase the porosity, 1 wt.% PVP was added into the dope solu- tion. PVP was fi rst dissolved in NMP solvent, followed by the addition of the PSf. The solution was stirred continuously until it became homoge- neous. The solution was then cast on a glass plate using a casting bar to a thickness of around 100 μ m. The cast polymer solution fi lm was kept for 30 s at ambient temperature before being immersed into coagulant (water) that was kept at room temperature. After coagulation, the sub- strate membrane was washed thoroughly with DI water to remove re- sidual solvent and kept wet at 5 °C prior to use. PES and PEI substrate membranes were prepared in the same way as PSf. Those membranes were denoted as PSf, PES and PEI substrates, respectively, hereafter.
Show more

8 Read more

Development of MoS2 CNT composite thin film from layered MoS2 for lithium batteries

Development of MoS2 CNT composite thin film from layered MoS2 for lithium batteries

Single-walled carbon nanotube (arc-discharge SWNT pur- chased from Iljin Nanotech Co., Seoul, Korea) dispersions were prepared by adding the nanotubes to a 10-mL cylindri- cal vial containing an aqueous solution of 5 mgmL 1 PEDOT:PSS (Baytron PH500, purchased from H.C. Stark), such that the nanotube concentration was 1 mgmL 1 . This dispersion was subjected to 5 min of high-power tip sonica- tion (VibraCell CVX, 750 W, 20% amplitude, 60 kHz) before being placed in a sonic bath (Branson 2510-MT) for 1 h and subjected to another 5 min of high-power sonication. These dispersions were blended in the ratio required to give the desired SWNT/PEDOT:PSS mass fraction. The mixtures were then sonicated for 15 min in a sonic bath to homogenize. The resulting dispersions were vacuum-filtered using 0.45 lm polyvinylidene fluoride (PVDF) filter membranes (MF-Millipore membrane, 47-mm diameter) to produce thick films. The thickness of these films was controlled by the volume of dispersion filtered and hence the deposited mass. Deposited films were washed with 200 mL of deionized water, dried under vacuum for 24 h at 60 C, and peeled from the filter membrane to give a robust free standing film.
Show more

5 Read more

Fabrication and Modification of Thin-Film Composite Hollow Fiber NF Membranes

Fabrication and Modification of Thin-Film Composite Hollow Fiber NF Membranes

The values of the NaCl rejection and the water permeability are presented in Figure 10, for various TETA concentrations. From Figure 10, it can be seen that the salt rejection increased from 15.17 to 25.44% with increasing the TETA concentration from 0.5 to 10% (w/v). This increase could be attributed to the expansion of the polymerization reaction in the presence of TETA and denser polyamide active layer (Figure 5). In fact, with the addition of TETA to the aqueous solution due to the expansion of polymerization reaction from third sides, polyamide active layer with more density and hydrophilicity was formed, which can lead to increase the flux. Also, from the AFM images (Figure 7), it can be observed that the surface roughness is reduced. As a result, it can be concluded that lower surface roughness can lead to lower fouling tendency, which this can be considered as a flux increasing reason. Increasing the TETA concentration was continued from 1% to 10% in the aqueous solution, which leads to flux decreased slightly and then not showed much change. To explain the flux decline, it can be concluded, though adding TETA, hydrophilic amide groups and free amino groups on the membrane surface increased, but increased membrane density is dominated by the increased hydrophilicity, which eventually would lead to a slight decrease in the flux. Finally, according to the rejection rate and the permeate flux, the concentration of 4% TETA, which have relatively high rejection and acceptable flux, was selected as the optimum concentration in order to get stable separation performance in further experiments.
Show more

8 Read more

Formation of thin film composite nanofiltration membrane: Effect of polysulfone substrate characteristics

Formation of thin film composite nanofiltration membrane: Effect of polysulfone substrate characteristics

In this work, polysulfone (PSf) substrates with different properties were made by varying the polymer con- centration in the dope solution in the range 12 – 20 wt.%. Polyamide (PA) thin layers were then formed via interfacial polymerization between piperazine and trimethylchloride over the PSf substrates. Both top PA thin layers and bottom PSf substrates were characterized with respect to physicochemical properties, structural morphology, and water fl ux/salt rejection to investigate the in fl uence of substrate properties on the characteristics of PA thin layers. Physical properties of the PA layers were reported to be altered using different PSf substrate properties and were in good agreement with the change in water flux. From the FESEM pictures, it is found that the thickness of PA layer increased as the surface pore size of sup- port membrane decreased. The change in the membrane structural properties in particular pore size is found to portray significant contribution to the changes of formed PA layer. Interestingly, only slight changes on Na 2 SO 4 and MgSO 4 salt rejection were reported on any TFC membranes. Considering both
Show more

10 Read more

Modification of Thin Film Composite Nanofiltration Membrane using Silver Nanoparticles: Preparation, Characterization and Antibacterial Performance

Modification of Thin Film Composite Nanofiltration Membrane using Silver Nanoparticles: Preparation, Characterization and Antibacterial Performance

Membrane fouling occurs when there is a blockage in the membrane pores during filtration by adsorption of particulates and compounds onto the membrane surface or within the membrane pores. Pore blocking slows down the permeate production rate and increases the difficulty of the membrane filtration operation. In general, there are four types of fouling, including organic fouling, crystalline/scaling fouling, particle/colloid fouling and biofouling [2]. Various attempts have been done to reduce fouling effect. For instance, pre-treatment of the feed stream [3], modification of the membrane surface features (e.g. hydrophobic or hydrophilic surface, and electronegative or electropositive charge) [4] and periodic cleaning [5]. For example, small attachment of microorganism (i.e. bacteria and viruses), excrete extracellular polymeric substances (EPS) on the membrane surface could cause biofilms formation. Thus, this can enhance biofouling to occur later on [6].
Show more

7 Read more

Thin Film Composite and/or Thin Film Nanocomposite Hollow Fiber Membrane for Water Treatment, Pervaporation and Gas/Vapor Separation

Thin Film Composite and/or Thin Film Nanocomposite Hollow Fiber Membrane for Water Treatment, Pervaporation and Gas/Vapor Separation

Zheng et al. [20] prepared positively charged thin-film composite hollow fiber nanofiltration membranes by the dip-coating method using polypropylene hollow fiber microfiltration membrane as support. The coating materials were polyvinyl alcohol (PVA) and polyquaternium-10 (the reaction product of hydroxyethyl cellulose with a trimethylammonium substituted epoxide, PQ-10) and glutaraldehyde used as cross-linking agent. By using the submerged filtration technique, it was observed that the rejections of Brilliant Green, Victoria Blue B and Crystal Violet were 99.8%, 99.8% and 99.2%, respectively. The permeation properties were estimated through pressurized cross-flow permeation technique. Inorganic salts such as CaCl 2 , MaCl 2 , NaCl, MgSO 4 and Na 2 SO 4 of analytical grade
Show more

44 Read more

Effect of change in trans-membrane pressure differences on the efficiency of a thin film reverse osmosis membrane.

Effect of change in trans-membrane pressure differences on the efficiency of a thin film reverse osmosis membrane.

Abstract : A spiral wound thin film composite reverse osmosis membrane was tested for its efficiency for the removal of certain water contaminants and its efficiency in terms of permeate generation. The experiment was performed using solutions of known concentrations of the contaminants at two trans membrane pressure differences. The synthetic solution concentrations used exceeded the permissible limits i.e., 100ppm of nitrate, 10ppm of fluoride, 1000ppm of chloride, 30ppm of iron, 25ppm of chromium, 5ppm of cadmium, and 25ppm of copper. The efficiency of membrane towards the removal of different contaminant from the feed solutions ranged from 88.8 to 99.8%. The contaminant concentrations in permeate were well below the standard limits for drinking water. The efficiency of permeate generation was low. However the efficiency of permeate generation increased at higher trans membrane pressure difference with no decline in removal efficiency of the contaminants, rather it improved. The type of the contaminants did not have a significant difference on the permeate recovery.
Show more

6 Read more

Dopamine Incorporated Forward Osmosis Membranes with High Structural Stability and Chlorine Resistance

Dopamine Incorporated Forward Osmosis Membranes with High Structural Stability and Chlorine Resistance

Abstract: The degradation and detachment of the polyamide (PA) layer in thin-film composite (TFC) membranes due to chlorine based chemical cleaning and material difference of PA layer and substrate are two major bottlenecks of forward osmosis (FO) technology. In this study, a new type of FO membranes were prepared by controlling self-polymerization of dopamine (DA) in the aqueous phase and the reaction with trimesoyl chloride (TMC) during interfacial polymerization (IP) process. These membranes were characterized by attenuated total reflection Fourier transform infrared (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FESEM) and water contact angle measurements. The influence of synthesis parameters such as pH of the aqueous phase, reaction time, temperature, and monomer concentrations were systematically investigated. The optimized membrane showed enhanced structure stability in ethanol (7.1 times higher) and chlorine resistance (72.3 times higher) than the conventional Piperazine(PIP)/TMC membrane due to ( poly-dopamine ) PDA bio-adhesion and polyester groups in the membrane structure. In general, DA/TMC membranes could be an effective strategy to fabricate high-performance FO membranes with excellent structural stability and chlorine resistance.
Show more

12 Read more

Calix[4]Arene and Calix[8]Arene Langmuir Films: Surface Studies, Optical and Structural Characterizations

Calix[4]Arene and Calix[8]Arene Langmuir Films: Surface Studies, Optical and Structural Characterizations

Main materials in this study are 25, 26, 27, 28- tetrahydrocalix[4]arene (C4) and 49, 50, 51, 52, 53, 54, 55, 56-octahydroxycalix[8]arene (C8) (FIGURE 1) that purchased from Sigma-Aldrich. Each of the calixarenes was dissolved in chloroform (CHCl3) to produce 0.2 mg/ml of calixarene solution. The calixarenes and their organic solvent, CHCl3 (>99.8% purity) were used without additional purification procedure. Pieces of quartz with a dimension of 2.5 cm × 2.5 cm were selected as the substrate for calixarene LB thin film deposition. Proper cleaning method was utilized to ensure the cleanliness of the substrate. Initially, the substrates were cleaned with Decon 90 before rinsed with deionized (DI) water. Later, ultrasonication (40 kHz) of substrates with the sequences of acetone (10 minutes), DI water (2 minutes), propanol (10 minutes) and DI water (2 minutes) again before the drying process with a nitrogen gun take place. Finally, the substrates were being treated hydrophobically with 1,1,1,3,3,3-Hexamethyldisilazane (C 2 H 19 NSi 2 ) overnight to
Show more

6 Read more

Development of liposomal cosmeceuticals

Development of liposomal cosmeceuticals

A liposome is a tiny bubble (vesicle), made out of the same material as a cell membrane. Membranes are usually made of phospholipids, which are molecules that have a head group and a tail group. The head is attracted to water, and the tail, which is made of a long hydrocarbon chain, is repelled by water. Since then, liposomes have made their way to the market. Today, numerous lab scale but only a few large-scale techniques are available. Today, they are a very useful reproduction, reagent, and tool in various scientific disciplines, including mathematics and theoretical physics, biophysics, chemistry, colloid science, biochemistry, and biology. Liposomes with modified surfaces have also been developed using several molecules, such as glycolipids or sialic acid. Liposomes are used as model for artificial cells. Liposomes can also be designed to deliver drugs in other ways. The use of liposomes for transformation or transfection of DNA into a host of cell is known as lipofection. Liposome are widely used as carriers of active ingredients to human tissue and as lipid transfer vesicles to the skin. Liposomes find applications in pharmaceutical, cosmetic and other industrial field.
Show more

5 Read more

Show all 10000 documents...