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Browsing by Author "Yalcinkaya, Fatma"

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A Review on Membrane Technology and Chemical Surface Modification for the Oily Wastewater Treatment
(MDPI, 2020-03-11) Yalcinkaya, Fatma; Boyraz, Evren; Maryška, Jiří; Kučerová, Klára
Cleaning of wastewater for the environment is an emerging issue for the living organism. The separation of oily wastewater, especially emulsified mixtures, is quite challenged due to a large amount of wastewater produced in daily life. In this review, the membrane technology for oily wastewater treatment is presented. In the first part, the global membrane market, the oil spill accidents and their results are discussed. In the second and third parts, the source of oily wastewater and conventional treatment methods are represented. Among all methods, membrane technology is considered the most efficient method in terms of high separation performance and easy to operation process. In the fourth part, we provide an overview of membrane technology, fouling problem, and how to improve the self-cleaning surface using functional groups for effectively treating oily wastewater. The recent development of surface-modified membranes for oily wastewater separation is investigated. It is believed that this review will promote understanding of membrane technology and the development of surface modification strategies for anti-fouling membranes.
Effect of Laminating Pressure on Polymeric Multilayer Nanofibrous Membranes for Liquid Filtration
(MDPI, 2019-04-24) Yalcinkaya, Fatma; Hrůza, Jakub
In the new century, electrospun nanofibrous webs are widely employed in various applications due to their specific surface area and porous structure with narrow pore size. The mechanical properties have a major influence on the applications of nanofiber webs. Lamination technology is an important method for improving the mechanical strength of nanofiber webs. In this study, the influence of laminating pressure on the properties of polyacrylonitrile (PAN) and polyvinylidene fluoride (PVDF) nanofibers/laminate was investigated. Heat-press lamination was carried out at three different pressures, and the surface morphologies of the multilayer nanofibrous membranes were observed under an optical microscope. In addition, air permeability, water filtration, and contact angle experiments were performed to examine the effect of laminating pressure on the breathability, water permeability and surface wettability of multilayer nanofibrous membranes. A bursting strength test was developed and applied to measure the maximum bursting pressure of the nanofibers from the laminated surface. A water filtration test was performed using a cross-flow unit. Based on the results of the tests, the optimum laminating pressure was determined for both PAN and PVDF multilayer nanofibrous membranes to prepare suitable microfilters for liquid filtration.
Electron-Beam Irradiation of the PLLA/CMS/beta-TCP Composite Nanofibers Obtained by Electrospinning
(MDPI, 2020-07) Yusof, Mohd Reusmaazran; Shamsudin, Roslinda; Zakaria, Sarani; Hamid, Muhammad Azmi Abdul; Yalcinkaya, Fatma; Abdullah, Yusof; Yacob, Norzita
Nanofibrous materials produced by electrospinning processes have potential advantages in tissue engineering because of their biocompatibility, biodegradability, biomimetic architecture, and excellent mechanical properties. The aim of the current work is to study the influence of the electron beam on the poly L-lactide acid/ carboxy-methyl starch/beta-tricalcium phosphate (PLLA/CMS/beta-TCP) composite nanofibers for potential applications as bone-tissue scaffolds. The composite nanofibers were prepared by electrospinning in the combination of 5%v/vcarboxy-methyl starch (CMS) and 0.25 wt% of beta-TCP with the PLLA as a matrix component. The composites nanofibers were exposed under 5, 30, and 100 kGy of irradiation dose. The electron-beam irradiation showed no morphological damage to the fibers, and slight reduction in the water-contact angle and mechanical strength at the higher-irradiation doses. The chain scission was found to be a dominant effect; the higher doses of electron-beam irradiation thus increased the in vitro degradation rate of the composite nanofibers. The chemical interaction due to irradiation was indicated by the Fourier transform infrared (FTIR) spectrum and thermal behavior was investigated by a differential scanning calorimeter (DSC). The results showed that the electron-beam-induced poly L-lactide acid/carboxy-methyl starch/beta-tricalcium phosphate (PLLA/CMS/beta-TCP) composite nanofibers may have great potential for bone-tissue engineering.
Electron-Beam Irradiation of the PLLA/CMS/β-TCP Composite Nanofibers Obtained by Electrospinning
(MDPI, 2020) Yusof, Mohd Reusmaazran; Shamsudin, Roslinda; Zakaria, Sarani; Abdul Hamid, Muhammad Azmi; Yalcinkaya, Fatma; Abdullah, Yusof; Yacob, Norzita
Nanofibrous materials produced by electrospinning processes have potential advantages in tissue engineering because of their biocompatibility, biodegradability, biomimetic architecture, and excellent mechanical properties. The aim of the current work is to study the influence of the electron beam on the poly L-lactide acid/ carboxy-methyl starch/β-tricalcium phosphate (PLLA/CMS/β-TCP) composite nanofibers for potential applications as bone-tissue scaffolds. The composite nanofibers were prepared by electrospinning in the combination of 5% v/v carboxy-methyl starch (CMS) and 0.25 wt% of β-TCP with the PLLA as a matrix component. The composites nanofibers were exposed under 5, 30, and 100 kGy of irradiation dose. The electron-beam irradiation showed no morphological damage to the fibers, and slight reduction in the water-contact angle and mechanical strength at the higher-irradiation doses. The chain scission was found to be a dominant effect; the higher doses of electron-beam irradiation thus increased the in vitro degradation rate of the composite nanofibers. The chemical interaction due to irradiation was indicated by the Fourier transform infrared (FTIR) spectrum and thermal behavior was investigated by a differential scanning calorimeter (DSC). The results showed that the electron-beam-induced poly L-lactide acid/carboxy-methyl starch/β-tricalcium phosphate (PLLA/CMS/β-TCP) composite nanofibers may have great potential for bone-tissue engineering.
Electrospun Polyacrylonitrile Nanofibrous Membranes for Point-of-Use Water and Air Cleaning
(MDPI, 2019-01) Roche, Remi; Yalcinkaya, Fatma
Novel electrospun polyacrylonitrile (PAN) nanofibrous membranes were prepared by using heat-press lamination under various conditions. The air permeability and the burst-pressure tests were run to select the membranes for point-of-use air and water cleaning. Membrane characterization was performed by using scanning electron microscopy, contact angle, and average pore size measurements. Selected membranes were used for both air dust filtration and cross-flow water filtration tests. Air dust filter results indicated that electrospun PAN nanofibrous membranes showed very high air-dust filtration efficiency of more than 99.99 % in between PM0.3 and PM2.5, whereas cross-flow filtration test showed very high water permeability over 600 L/(m(2)hbar) after 6 h of operation. Combining their excellent efficiency and water permeability, these membranes offer an ideal solution to filter both air and water pollutants.
Electrospun Polyamide-6 Nanofiber Hybrid Membranes for Wastewater Treatment
(2019-01) Yalcinkaya, Fatma; Yalcinkaya, Baturalp; Hrůza, Jakub
Electrospun nanofiber hybrid membranes have superior membrane performance due to their high specific surface area, narrow pore size, high porosity, and uniform pore size. Recently, increasing attention has been given to hydrophilic membranes such as polyamide 6 (PA6) in applications microfiltration and reverse osmosis. Electrospun PA6 nanofiber hybrid membranes have not found any real application due to their poor mechanical strength under high pressure. In this study, PA6 nanofiber layer was prepared using wire electrospinning method. Three supporting material with different adhesion method has been used to improve the mechanical properties of the membranes. Membranes were characterized with Scanning Electron Microscope images, pore size, and contact angle measurements. Tensile strength and the delamination tests were run to measure the mechanical properties of the membranes. Three types of wastewater were carried out during filtration; using real wastewater supplied from a company which consists of pitch and tar oils, engine oil/water mixture and kitchen oil/water mixture. Results indicated that the adhesion method and the supporting layer played a big role in the permeability of the membranes. The PA6 nanofiber hybrid membranes exhibited high water fluxes in even at low pressures which indicate that electrospun nanofiber membranes might be highly promising for microfiltration applications.
Fabrication and Characterization of Carboxymethyl Starch/Poly(l-Lactide) Acid/beta-Tricalcium Phosphate Composite Nanofibers via Electrospinning
(MDPI, 2019-10-18) Yusof, Mohd Reusmaazran; Shamsudin, Roslinda; Zakaria, Sarani; Hamid, Muhammad Azmi Abdul; Yalcinkaya, Fatma; Abdullah, Yusof; Yacob, Norzita
A natural polymer of carboxymethyl starch (CMS) was used in combination with the inorganic mineral of beta-Tricalcium Phosphate (beta-TCP) and Poly L-lactide (PLLA) to prepare composite nanofibers with the potential to be used as a biomedical membrane. beta-TCP contents varied in the range of 0.25% to 1% in the composition of PLLA and CMS. A mixed composition of these organic and inorganic materials was electro-spun to produce composite nanofibers. Morphological investigation indicated that smooth and uniform nanofibers could be produced via this technique. The average of the nanofiber diameters was slightly increased from 190 to 265 nm with the beta-TCP content but some agglomeration of particles began to impede in the fiber at a higher content of beta-TCP. It was observed that the fibers were damaged at a higher content of beta-TCP nanoparticles. With the presence of higher beta-TCP, the wettability of the PLLA was also improved, as indicated by the water contact angle measurement from 127.3 degrees to 118 degrees. The crystallization in the composite decreased, as shown in the changes in glass transition (T-g) and melting temperature (T-m) by differential scanning calorimeter (DSC) and X-ray diffraction analysis. Increases in beta-TCP contributed to weaker mechanical strength, from 8.5 to 5.7 MPa, due to imperfect fiber structure.
Fabrication and characterization of carboxymethyl starch/poly(l-lactide) acid/β-tricalcium phosphate composite nanofibers via electrospinning
(MDPI, 2019) Yusof, Mohd Reusmaazran; Shamsudin, Roslinda; Zakaria, Sarani; Hamid, Muhammad Azmi Abdul; Yalcinkaya, Fatma; Abdullah, Yusof; Yacob, Norzita
A natural polymer of carboxymethyl starch (CMS) was used in combination with the inorganic mineral of β-Tricalcium Phosphate (β-TCP) and Poly l-lactide (PLLA) to prepare composite nanofibers with the potential to be used as a biomedical membrane. β-TCP contents varied in the range of 0.25% to 1% in the composition of PLLA and CMS. A mixed composition of these organic and inorganic materials was electro-spun to produce composite nanofibers. Morphological investigation indicated that smooth and uniform nanofibers could be produced via this technique. The average of the nanofiber diameters was slightly increased from 190 to 265 nm with the β-TCP content but some agglomeration of particles began to impede in the fiber at a higher content of β-TCP. It was observed that the fibers were damaged at a higher content of β-TCP nanoparticles. With the presence of higher β-TCP, the wettability of the PLLA was also improved, as indicated by the water contact angle measurement from 127.3° to 118°. The crystallization in the composite decreased, as shown in the changes in glass transition (Tg) and melting temperature (Tm) by differential scanning calorimeter (DSC) and X-ray diffraction analysis. Increases in β-TCP contributed to weaker mechanical strength, from 8.5 to 5.7 MPa, due to imperfect fiber structure.
Incorporation of PVDF Nanofibre Multilayers into Functional Structure for Filtration Applications
(MDPI, 2019-09-29) Roche, Remi; Yalcinkaya, Fatma
Membranes are considered as a promising technology for separation and filtration processes. Here, novel polyvinylidene fluoride (PVDF) nanofibrous multilayer membranes were fabricated by wire-based industrial electrospinning equipment following by a lamination process. The lamination process was optimised under various applied temperature, force of lamination, and lamination time. Air permeability and burst-pressure tests were run to determine the optimum membranes for filtration application. The structures of the prepared membranes were characterised by scanning electron microscopy and pore-size analysis. The hydrophilic properties of the membranes were evaluated using water contact angle measurement, and the mechanical strength of the membranes was analysed. Air and water filtration tests were run to find the possible application of prepared membranes. The air filtration results showed that membranes had high filtration efficiencies: Over 99.00% for PM2.5, and PM0.1. The water filtration results indicated that permeability of the membranes changed from 288 to 3275 L/m2hbar. The successful preparation of such an interesting material may provide a new approach for the design and development of electrospun filter membranes.
Influence of Electrospinning Parameters on the Hydrophilicity of Electrospun Polycaprolactone Nanofibres
(2019) Tiyek, Ismail; Gunduz, Aysegul; Yalcinkaya, Fatma; Chaloupek, Jiri
In the present study, PCL (polycaprolactone) nanofibres were produced by the electrospinning method. The use of PCL electrospun biopolymer in biomedical applications has attracted considerable interest due to its chemical resistance, biodegradability, biocompatibility, and non-toxic characteristics. However, the hydrophobic nature of PCL polymer restricts the useage of PCL nanofibres for the cell adhesion and absorption. A hydrophilic and biocompatible PCL electrospun mat with a low water contact angle is an attractive strategy for development in tissue engineering and wound dressing. In this study, we demonstrate a feasible and simple method to produce hydrophilic PCL nanofibres for possible application in wound dressing. Chloroform/ethanol (EtOH) and chloroform/dimethylformamide (DMF) mixtures were used as two different solvent systems. The impact of the polymeric solution concentration, applied voltage, and solvent mixtures on the fibre surface morphology and water contact angle was investigated. Consequently, bead structures were observed at low concentrations but disappeared with increases in the concentration. It was observed that the size of beads decreased and the diameter of fibres increased with increasing voltage. The wettability of the webs changed from hydrophobic to hydrophilic with changes of the polymer concentration. The contact angle of the nanofibre mats decreased in both solvent systems as the concentration increased. The results showed that the lowest contact angle was obtained in 24% wt. PCL+chloroform/EtOH solution and was 68°. The highest contact angle was obtained in 4% wt. PCL+chloroform/EtOH solution and was 112°. Using this method, the surface hydrophilicity of the PCL nanofibres improved easily without any surface treatment.
Influence of Salts on Electrospinning of Aqueous and Nonaqueous Polymer Solutions
(Technická Univerzita v Liberci, 2015) Yalcinkaya, Fatma; Yalcinkaya, Baturalp; Jirsák, Oldřich
A roller electrospinning system was used to produce nanofibres by using different solution systems. Although the process of electrospinning has been known for over half a century, knowledge about spinning behaviour is still lacking. In this work, we investigated the effects of salt for two solution systems on spinning performance, fibre diameter, and web structure. Polyurethane (PU) and polyethylene oxide (PEO) were used as polymer, and tetraethylammonium bromide and lithium chloride were used as salt. Both polymer and salt concentrations had a noteworthy influence on the spinning performance, morphology, and diameter of the nanofibres. Results indicated that adding salt increased the spinnability of PU. Salt created complex bonding with dimethylformamide solvent and PU polymer. Salt added to PEO solution decreased the spinning performance of fibres while creating thin nanofibres, as explained by the leaky dielectric model.
New Methods in the Study of Roller Electrospinning Mechanism
(Technická Univerzita v Liberci, ) Yalcinkaya, Fatma
ONE-DIMENSIONAL NANOFIBERS: APPLICATION IN MEMBRANE TECHNOLOGY
(2021-11-08) Yalcinkaya, Fatma
This habilitation thesis is prepared based on the author's contributions to the nanofiber membranes in water treatment. First, the author tried to determine the main problems why the nanofibers cannot use in water domain applications in the market, then tried to suggest solutions, solve and clarify each problem. The thesis provides a comprehensive description of the issue based on the current state of knowledge. The structure of the thesis is as follows: Chapter 1 is a general introduction that shows the main problems why the nanofibers cannot take place in liquid filtration. In Chapter 2, electrospinning process and parameters for the forming of the nanofiber web are introduced. We discuss the needle-free electsopinning system developed by the Technical University of Liberec (TUL). Chapter 3 focuses on membrane technology and nanofibers in membrane technology. Chapter 4 is represented the work of the author in cooperation with several authors from different institutions and countries in the field of nanofiber web formation, membrane preparation, application, and comment on their contribution to the scientific community. Chapter 5 is the conclusion of the work. In the Appendix part, the author includes scientific publications together with co-authors from the same or different institutions.
Polyvinyl Butyral (PVB) Nanofiber/Nanoparticle-Covered Yarns for Antibacterial Textile Surfaces
(MDPI, 2019-09-03) Yalcinkaya, Fatma; Komárek, Michal
In this study, nanoparticle-incorporated nanofiber-covered yarns were prepared using a custom-made needle-free electrospinning system. The ultimate goal of this work was to prepare functional nanofibrous surfaces with antibacterial properties and realize high-speed production. As antibacterial agents, we used various amounts of copper oxide (CuO) and vanadium (V) oxide (V2O5) nanoparticles (NPs). Three yarn preparation speeds (100 m/min, 150 m/min, and 200 m/min) were used for the nanofiber-covered yarn. The results indicate a relationship between the yarn speed, quantity of NPs, and antibacterial efficiency of the material. We found a higher yarn speed to be associated with a lower reduction in bacteria. NP-loaded nanofiber yarns were proven to have excellent antibacterial properties against Gram-negative Escherichia coli (E. coli). CuO exhibited a greater inhibition and bactericidal effect against E. coli than V2O5. In brief, the studied samples are good candidates for use in antibacterial textile surface applications, such as wastewater filtration. As greater attention is being drawn to this field, this work provides new insights regarding the antibacterial textile surfaces of nanofiber-covered yarns.
Preparation of various nanofiber layers using wire electrospinning system
(ELSEVIER, RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS, 2019-12) Yalcinkaya, Fatma
This study focuses on the preparation of various polymeric nanofibers using new industrial production equipment a wire electrospinning system. The disadvantages of each polymeric nanofiber were improved by mixing suitable polymer/polymer-solvent/solvent systems. A total of 9 types of polymers (polyamide, polyvinylidene fluoride, polyacrylonitrile, polyurethane, polysulfone, chitosan, cellulose acetate, polyvinyl butyral, and polycaprolactone) and their mixtures were electrospun using a wire electrospinning system. The resultant fiber surface morphology showed that the wire electrospinning method is suitable for the production of various polymers on an industrial scale. Moreover, polymer mixtures changed the adhesion properties, increased productivity and reduced the fiber diameter of nanofibers. (C) 2016 The Author. Production and hosting by Elsevier B.V. on behalf of King Saud University. Thisis an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Separation of racemic compound by nanofibrous composite membranes with chiral selector
(ELSEVIER, RADARWEG 29, 1043 NX AMSTERDAM, NETHERLANDS, 2020-02-15) Gaálová, Jana; Yalcinkaya, Fatma; Cuřínová, Petra; Kohout, Michal; Yalcinkaya, Baturalp; Koštejn, Martin; Jirsák, Jan; Stibor, Ivan; Bara, Jason E.; Van der Bruggen, Bart; Izák, Pavel
A series of unique composite membranes formed from a nano&fibrous material with different amounts of a chiral selector was used for separation of chiral drugs. The membrane performances were demonstrated through sorption tests, wherein they were soaked in an aqueous solution of racemic D, L-tryptophan (a model chiral drug). The changes in concentration of both enantiomers over time were monitored by HPLC analysis. During 100 days, a blank membrane (without the chiral selector) exhibited no sorption activity. The membranes containing the selector had no influence on the amount of D-enantiomer, while the L-enantiomer was preferentially adsorbed on each membrane. The intensity of the sorption was found to be a direct function of the amount of the selector contained in a particular membrane. The separation of the same model chiral compound was further studied in diffusion cells by pertraction. The preferential sorption of L-tryptophan in the feed underlined the crucial importance of the selector in an active layer in view of chiral recognition of enantiomers. Due to the exclusive membrane material, the retention of L-tryptophan in the membrane materials did not block the passage of D-enantiomer into the permeate at any point during the experiment. Moreover, the nanomaterial in the active layer assured the distribution of the selector to the point that only 50% of (S, S)-1,2-diaminocyclohexane in one part of the active layer was sufficient to achieve 99% of enantioselectivity. The membranes - fresh and used - were analysed by Fourier-transform infrared (FTIR) spectroscopy and characterized by scanning electron microscopy (SEM) confirming the stability of the tested membranes. To complete the study, the role of the polyamide active layer in chiral recognition of tryptophan enantiomers was proposed.
Surface-modified nanofibrous PVDF membranes for liquid separation technology
(2019) Boyraz, Evren; Yalcinkaya, Fatma; Hrůza, Jakub; Maryška, Jiří
Preparing easily scaledup, cost-effective, andrecyclablemembranes for separation technology is challenging. In the present study, a unique and newtype ofmodified polyvinylidene fluoride (PVDF) nanofibrous membrane was prepared for the separation of oil-water emulsions. Surface modification was done in two steps. In the first step, dehydrofluorination of PVDF membranes was done using an alkaline solution. After the first step, oil removal and permeability of themembraneswere dramatically improved. In the second step, TiO2 nanoparticles were grafted onto the surface of the membranes. After adding TiO2 nanoparticles, membranes exhibited outstanding anti-fouling and self-cleaning performance. The as-prepared membranes can be of great use in new green separation technology and have great potential to deal with the separation of oil-water emulsions in the near future.

Browsing by Author "Yalcinkaya, Fatma"

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