Antimicrobial properties of polymeric nanofibrous membranes containing ferrous sulphate

This paper reposts on nanofibers of polymers doped with ferrous sulphate (FeSO4) possibly in combination with quaternary ammonium salt (QAS) prepared by electrospinning. Three types of polymers (polyvinylidene fluoride/PVDF, polylactic acid/PLA and polyurethane/PU) with good electrospinning processability and good mechanical properties of nanofibers were chosen. The prepared nanofibrous membranes were characterised in terms of morphology of the fibres assessed by SEM, and the pore sizes were determined by porometry. The leaching test showed a firm anchoring of the additive in the nanofiber structure. Antimicrobial activity was monitored after 0 h, 4 h and 24 h using Staphylococcus aureus (CCM 4516) and Klebsiella pneumoniae (CCM 4415) strains. Furthermore, aerosol filtration efficycy was dermined and also quality factor of filtration. The membrane prepared from PU doped with FeSO4 showed the best antibacterial efficiency. The porosity and morphology of the nanofibrous membrane effectively contributed to the trapping of microorganisms. This system was also evaluated as the most suitable for the electrospinning process from the effectivity point of view. Spinning ang dopping process of preparation is easily applicatbole to the the industrial conditions of production which is very importatnt aspect of this submitted scientifique work. © 2021 NANOCON Conference Proceedings - International Conference on Nanomaterials. All rights reserved.Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT: RP/CPS/2020/00

An estimate of the onset of beadless character of electrospun nanofibers using rheological characterization

Electrospinning represents the very effective process of producing nanofibrous mats. This process is influenced by a number of mutually and strongly interlaced entry parameters (characteristics of polymer, solvent, process parameters) and their participation in the resulting nanofiber quality. The appearance of nanofibers is a result of the necessary primary experimental parameter setting within an acceptable range. However, finer analysis of nanofiber quality depends on the proper choice of these individual factors. The aim of this contribution is to evaluate one of the key factors—polymer concentration—with respect to the presence or absence of bead formation. This passage can be approximated by rheological oscillatory measurements when a sudden decrease in phase angle indicates this change. It replaces otherwise time-and cost-consuming trial-and-error experiments. This approach was tested using three different materials: solutions of poly(vinylidene fluoride-co-hexafluoropropylene), poly(vinyl butyral), and poly(ethylene oxide). © 2021 by the authors. Licensee MDPI, Basel, Switzerland.Ministry of Education, Youth and Sports of the Czech RepublicMinistry of Education, Youth & Sports - Czech Republic [LTC 19034]; COST ActionsEuropean Cooperation in Science and Technology (COST) [CA17107]European Cooperation in Science and Technology, COST: CA17107; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT: LTC 1903

Nanostructures for air filtration. Filtration properties in range of maximum penetrating particle sizes

End user customers and legislation of European countries require to classify the air filtration materials for ultra- fine particles separation in range of maximum penetrating particle size (MPPS). The filtration properties of nanostructured materials based on various polymers at comparable conditions (the same pressure drops) have been evaluated. © 2019 Author(s).Technology Agency of the Czech Republic [TE01020216]; Ministry of Education, Youth and Sports of the Czech Republic - Program NPU I [LO1504

The adsorption, kinetics, and interaction mechanisms of various types of estrogen on electrospun polymeric nanofiber membranes

This study focuses on the adsorption kinetics of four highly potent sex hormones (estrone (E1), 17 beta-estradiol (E2), 17 alpha-ethinylestradiol (EE2), and estriol (E3)), present in water reservoirs, which are considered a major cause of fish feminization, low sperm count in males, breast and ovarian cancer in females induced by hormonal imbalance. Herein, electrospun polymeric nanostructures were produced from cellulose acetate, polyamide, polyethersulfone, polyurethanes (918 and elastollan), and polyacrylonitrile (PAN) to simultaneously adsorbing these estrogenic hormones in a single step process and to compare their performance. These nanofibers possessed an average fiber diameter in the range 174-330 nm and their specific surface area ranged between 10.2 and 20.9 m(2) g(-1). The adsorption-desorption process was investigated in four cycles to determine the effective reusability of the adsorption systems. A one-step high-performance liquid chromatography technique was developed to detect and quantify concurrently each hormone present in the solution. Experimental data were obtained to determine the adsorption kinetics by applying pseudo-first-order, pseudo-second-order and intraparticle diffusion models. Findings showed that E1, E2 and EE2 best fitted pseudo-second-order kinetics, while E3 followed pseudo-first-order kinetics. It was found that polyurethane Elastollan nanofibers had maximum adsorption capacities of 0.801, 0.590, 0.736 and 0.382 mg g(-1) for E1, E2, EE2 and E3, respectively. In addition, the results revealed that polyurethane Elastollan nanofibers had the highest percentage efficiency of estrogens removal at similar to 58.9% due to its strong hydrogen bonding with estrogenic hormones, while the least removal efficiency for PAN at similar to 35.1%. Consecutive adsorption-desorption cycles demonstrated that polyurethane maintained the best efficiency, even after being repeatedly used four times compared to the other polymers. Overall, the findings indicate that all the studied nanostructures have the potential to be effective adsorbents for concurrently eradicating such estrogens from the environment.Ministry of Education, Youth and Sports of the Czech RepublicMinistry of Education, Youth & Sports - Czech Republic [RP/CPS/2020/002]; Internal Grant Agency of TBU in Zlin [IGA/CPS/2020/002]; Technological Agency of the Czech Republic [FW01010588

The adsorptive behaviour of electrospun hydrophobic polymers for optimized uptake of estrogenic sex hormones from aqueous media: kinetics, thermodynamics, and reusability study

Background: Estrogenic hormones as micropollutants in water systems cause severe adverse effects on human health and marine life, leading to fatal diseases, such as breast, ovarian, and prostate cancer. Electrospun polymers have proven high stability and impressive performance in adsorption removal. In this study, electrospun polysulfone (PSU), polyvinylidene fluoride, and polylactic acid were prepared and characterized using scanning electron microscope (SEM), fourier-transform intrared spectroscopy (FTIR), thermogravimetric analysis (TGA), Brunauer Emmett Teller (BET), surface area measurement X-Ray diffraction (XRD), and porometry. Results: Nanofibers possess a mean fiber diameter of 149–183 nm and a specific surface area of 1.6–6.3 m2/g. The adsorption efficiency of the simultaneous removal of estrone (E1), 17β-estradiol (E2), estriol (E3), and 17α-ethinylestradiol (EE2) in a mixed concentration was investigated using high performace liquid chromatography (HPLC). The results indicate that spun PSU fibers exhibited the highest removal of all four estrogens, with a maximum removal efficiency of 71.2%, 65.9%, 56.9%, and 36.1% and adsorption capacity of 0.508, 0.703, 0.550, and 0.354 mg/g for E1, EE2, E2, and E3, respectively. Additionally, the adsorption was optimised by varying parameters, such as concentration of adsorbate, pH, adsorbent dosage, and temperature, to statistically analyse one-way variance using ANOVA. The pseudo-second-order is best fitted for E1, EE2, and E2, while the pseudo-first-order is best for E3. The Langmuir–Freundlich isothermal model was most suitable for evaluation, and the thermodynamics depicted the adsorption to be exothermic and spontaneous. Conclusion: The results indicate that spun PSU can be an efficient adsorbent in the simultaneous elimination of estrogens from wastewater and it exhibits a high regeneration performance of over 60% after six adsorption–desorption cycles. © 2022 Society of Chemical Industry (SCI). © 2022 Society of Chemical Industry (SCI).IGA/CPS/2022/003; Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT: RP/CPS/2022/002, RP/CPS/2022/005Ministry of Education, Youth, and Sports of the Czech Republic [RP/CPS/2022/002, RP/CPS/2022/005]; Internal Grant Agency of TBU in Zlin [IGA/CPS/2022/003

Highly efficient affinity anchoring of gold nanoparticles on chitosan nanofibers via dialdehyde cellulose for reusable catalytic devices

Polysaccharides are often utilized as reducing and stabilizing agents and as support in the synthesis of gold nanoparticles (AuNPs). However, using approaches like spin coating or dip coating, AuNPs are generally bound to the support only by weak interactions, which can lead to decreased stability of the composite. Here, a two-stage approach for the preparation of composites with covalently anchored AuNPs is proposed. First, 5 nm AuNPs with high catalytic activity for the reduction of 4-nitrophenol (TOF = 15.8 min−1) were synthesized and stabilized using fully oxidized and solubilized 2,3-dialdehyde cellulose (DAC). Next, the carbonyl groups in the shell of prepared nanoparticles were used to tether AuNPs to chitosan nanofibers with quantitative efficacy in a process that we termed “affinity anchoring”. Schiff bases formed during this process were subsequently reduced to secondary amines by borohydride, which greatly improved the stability of the composite in the broad pH range from 3 to 9. The catalytic efficacy of the resulting composite is demonstrated using a model catalytic device, showing high stability, fast conversion rates, and direct reusability. © 2023 Elsevier LtdDKRVO, (RP/CPS/2022/007); Tomas Bata University in Zlin, TBU, (IGA/CPS/2023/006); Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT; Grantová Agentura České Republiky, GA ČR, (23-07361S); Masarykova Univerzita, MU, (MUNI/A/1298/2022

Investigation of arsenic removal from aqueous solution through selective sorption and nanofiber-based filters

Background: This research paper focuses on removing of arsenic from contaminated water via a nanofibrous polymeric microfiltration membrane, applied in prospective combination with an inorganic sorbent based on iron oxide hydroxide FeO(OH). Materials and methods: Nanofibrous materials were prepared by electrospinning from polyurethane selected by an adsorption test. The chemical composition (FTIR), morphology (SEM, porometry) and hydrophilicity (contact angle) of the prepared nanostructured material were characterized. The process of eliminating arsenic from the contaminated water was monitored by atomic absorption spectroscopy (AAS). The adsorption efficiency of the nanofibrous material and the combination with FeO(OH) was determined, the level of arsenic anchorage on the adsorption filter was assessed by a rinsing test and the selectivity of adsorption in arsenic contaminated mineral water was examined. Results: It was confirmed that the hydrophilic aromatic polyurethane of ester type PU918 is capable of capturing arsenic by complexation on nitrogen in its polymer chains. The maximum As removal efficiency was around 62 %. Arsenic was tightly anchored to the polymeric adsorbent. The adsorption process was sufficiently selective. Furthermore, it was found that the addition of even a small amount of FeO(OH) (0.5 g) to the nanofiber filter would increase the efficiency of As removal by 30 %. Conclusions: The presented results showed that an adsorption filter based on a polyurethane nanostructured membrane added with an inorganic adsorbent FeO(OH) is a suitable way for the elimination of arsenic from water. However, it is necessary to ensure perfect contact between the surface of the nanostructure and the filtered medium. © 2021, Springer Nature Switzerland AG.Technological Agency of the Czech Republic [TJ02000629]; Ministry of Education, Youth and Sports of the Czech RepublicMinistry of Education, Youth & Sports - Czech Republic [LO1504, RP/CPS/2020/002]Technologická Agentura České Republiky: TJ02000629; Kementerian Pendidikan Malaysia, KP

Efficient Cu2+, Pb2+ and Ni2+ ion removal from wastewater using electrospun DTPA-modified chitosan/polyethylene oxide nanofibers

Diethylenetriaminepentaacetic acid-modified chitosan/polyethylene oxide nanofibers (CS-DTPA/PEO NFs) were developed for enhanced heavy metal ion adsorption. These nanofibers were prepared by electrospinning, and their morphology and structure were investigated by scanning electron microscopy (SEM), and Fourier-transform infrared spectroscopy (FTIR), respectively. The ability of CS-DTPA/PEO NFs to removing copper (Cu2+), lead (Pb2+) and nickel (Ni2+) ions from aqueous solutions was tested at room temperature. The effects of [DTPA]/[NH2] molar ratio, pH and initial concentration of metal ions on their absorption capacity were investigated to optimize process conditions, using pseudo-first and apparent-second-order, Boyd and intraparticle diffusion models to determine the rate-limiting step of metal ions adsorption. In turn, Freundlich, Langmuir, Temkin and Dubinin-Radushkevich isotherm models were used to describe the experimental data. The results demonstrate a decrease in the ability of CS-DTPA/PEO NFs to adsorb metal ions in the following order: Cu2+>Pb2+>Ni2+. The adsorption equilibrium is established after 90 min from the first contact with solutions containing the metal ions, and data are described using the Langmuir isotherm model. The maximal adsorption capacities of CS-DTPA/PEO NFs for Cu2+, Pb2+ and Ni2+ions were 177, 142, 56 mg g−1, respectively. The stability and reproducibility of CS-DTPA/PEO NFs were determined after five adsorption–desorption tests. © 2020Ministry of Education, Youth and Sports of the Czech RepublicMinistry of Education, Youth & Sports - Czech Republic [NPU I LO1504, CZ.02.2.69/0.0/0.0/16_027/0008464]; Ministry of Science and Higher Education of the Russian Federation [WSWW2020-0011

Effect of polyurethane structure on arsenic adsorption capacity in nanofibrous polymer/ferrous sulphate-based systems

This study investigates the effect of the nanofibrous polymeric structure of an adsorptive material, modified with an immobilized inorganic sorbent based on ferrous sulphate, on the capacity of the material to remove arsenic from contaminated water. Nanofibrous materials were prepared by electrospinning from polyurethane types selected using a primary adsorption test. The functional groups and chemical composition (FTIR, EDX), morphology (SEM, porometry) and hydrophilicity (contact angles) of the prepared nanostructured materials were determined in order to assess the effect of composition and structure on the removal of arsenic. The process of arsenic removal was monitored by atomic absorption spectroscopy (AAS). It was found that certain samples of polyurethanes, particularly self-synthesized aromatic polyurethane of an ester type, PU918, could remove arsenic by complexation on nitrogen in their polymer chains. The greatest efficiency for arsenic removal was ca. 60% (initial c(As) = 150 mu g L-1). It was also found that adding even a small amount (1 wt%) of an inorganic adsorbent based on ferrous sulphate into the fibre mass of the nanofibrous structure would increase the efficiency up to 90% as a result of a chemical reaction between the additive and arsenic ions. The extent and rate of adsorption were described by kinetic and isotherm models. The adsorption process is well characterized by a pseudo-second-order kinetic model and both Freundlich and Langmuir isotherm models. High adsorption capacity and rate are the basis for the use of nanofibrous material in filters for arsenic separation.Technological Agency of the Czech Republic [TJ02000269]; Ministry of Education Youth and Sports of the Czech Republic-programme DKRVO [RP/CPS/2022/002

The cytisine-enriched poly(3-hydroxybutyrate) fibers for sustained-release dosage form

The polymeric cytisine-enriched fibers based on poly(3-hydroxybutyrate) were obtained using electrospinning method. The biocompatibility study, advanced thermal analysis and release of cytisine from the poly(3-hydroxybutyrate) fibers were carried out. The nanofibers' morphology was evaluated by scanning electron microscopy. The formation and description of phases during the thermal processes of fibers by the advanced thermal analysis were examined. The new quantitative thermal analysis of polymeric fibers with cytisine phases based on vibrational, solid and liquid heat capacities was presented. The apparent heat capacity of fibers was measured using the standard differential scanning calorimetry. The quantitative analysis allowed for the study of the glass transition and melting/crystallization process. The mobile amorphous fraction, degree of crystallinity and rigid amorphous fraction were determined depending on the thermal history of semicrystalline polymeric fibers. Furthermore, the cytisine dissolution behaviour was studied. It was observed that the kinetic of the release from polymeric nanofiber is delayed than for the marketed product. The immunosafety of the tested polymeric nanofibers with cytisine was confirmed by the Food and Drug Agency Guidance as well as the European Medicines Agency. The polymeric matrix with cytisine seems to be a promising candidate for the prolonged release formulation. © 2023Ministerstvo Školství, Mládeže a Tělovýchovy, MŠMT: RP/CPS/2022/002; Narodowe Centrum Nauki, NCN: 2019/03/X/NZ7/00888; Narodowym Centrum Nauki, NC