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1.
J Environ Manage ; 302(Pt B): 114103, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34798586

RESUMO

In this study, (3-mercaptopropyl) triethoxysilane (MPTMS)-modified ordered mesoporous silica (OMS) materials were prepared using a post-grifting method, with MPTMS as the organic functionalized reagent. The OMS materials were analyzed by FT-IR spectra, N2 sorption, and small angle X-ray scattering to evaluate their potential for scavenging Cd2+ from water. Moreover, a (3-mercaptopropyl) triethoxysilane-functionalized ordered mesoporous silica modified polyvinylidene fluoride (MPTMS-OMS/PVDF) membrane was synthesized using the solvent phase inversion method to remediate wastewater containing heavy metal ions. The MPTMS-OMS was characterized by a maximum specific surface area of 422 m2/g, high surface hydrophilicity, and high pure water flux. The MPTMS-OMS/PVDF exhibited a dynamic adsorption capacity for Cd2+ in water. At an MPTMS-OMS content of 5 wt%, the Cd2+ removal efficiency was 90%, whereas the pure PVDF showed no Cd2+ adsorption capacity. These results highlight the potential of the MPTMS-OMS/PVDF membrane to eliminate Cd2+ during the decontamination of aqueous streams containing low-concentrations of contaminants.


Assuntos
Metais Pesados , Dióxido de Silício , Adsorção , Cádmio , Polímeros de Fluorcarboneto , Polivinil , Espectroscopia de Infravermelho com Transformada de Fourier , Água
2.
Chemosphere ; 286(Pt 2): 131705, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34333185

RESUMO

With regard to the treatment of multicomponent wastewaters, to construct multifunctional super-wetting membranes is highly attractive in current decade. In this work, a low-cost and novel NiFe2O4/TA/PVDF composite membrane was fabricated via a facile in-situ deposition method under vacuum system. In which, photo-response NiFe2O4 nanoparticles were immobilized on the surface of flexible PVDF base membrane via hydrophilic tannic acid (TA) as the binder. The resulting composite membrane exhibited a special superwettability of superamphilicity in air and underwater superoleophobicity with a nanoscale rough surface structure. One the one hand, NiFe2O4/TA/PVDF membrane can be used a reusable catalyst in Photo-Fenton degradation of organic dyes with high efficiency. On the other hand, the composite membrane can effectively separate emulsified oils from representative oil-in-water emulsions with excellent separation efficiency all above 99 % and relatively high flux (880-1525 Lm-2h-1 bar-1). More importantly, NiFe2O4/TA/PVDF composite membrane showed satisfactory processing efficiency, anti-fouling property and excellent reusability in deal with the mixed organic pollutants (water-insoluble emulsified oils and water-soluble organic dyes) existed in one aqueous system, which followed the procedure of initially photo-Fenton degradation of organic dyes emulsion and successively separation the remaining emulsion over the recovered membrane. This successful development of high-performance NiFe2O4/TA/PVDF composite membrane will provide a new candidate for both oil/water separation and organic wastewater treatment, as well as promote the utilization of spinel ferrites in the construction of multifunctional membrane for environmental purification.


Assuntos
Poluentes Ambientais , Membranas Artificiais , Polivinil , Taninos
3.
J Mech Behav Biomed Mater ; 125: 104891, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34689030

RESUMO

Polyvinylidene fluoride - hydroxyapatite composite filaments were processed by twin-screw extrusion at different processing angular velocities and characterized by scanning electron and atomic force microscopies, differential scanning calorimetry and tensile tests. Polymer-ceramic composites with a 0-3 connectivity were successfully obtained. Regardless of the used processing parameters, all composite filaments present very similar melting (∼152°C) and solidification (∼139°C) points and elastic moduli (∼1.0 GPa) for hydroxyapatite as dispersed phase in the composite with concentrations up to 25 wt%, indicating that they are adequate for twin-screw extrusion and 3D printing. However, the yield strength (∼29 MPa), ultimate tensile strength (∼36 MPa) and tensile point (∼29 MPa) parameters are similar only for hydroxyapatite concentrations up to 15 wt%, once higher concentrations of hydroxyapatite as dispersed phase result in fragile samples (∼50% lower for each studied property).


Assuntos
Durapatita , Polivinil , Polímeros de Fluorcarboneto , Polímeros , Impressão Tridimensional
4.
Chemosphere ; 287(Pt 3): 132212, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34547558

RESUMO

Amphiphilic copolymers containing hydrophilic and hydrophobic blocks represented by surfactants have proven to be more effective for modifying membranes than hydrophilic copolymers. However, studies on the effects of additive and coagulation bath pH on the morphology and properties of surfactant-modified membranes have rarely been reported. Hence, this study aims to investigate the effects of the additive dosage and the coagulation bath pH on the mechanisms of phase inversion and performance improvement of amphoteric fluorocarbon special surfactant (FS-50) blended PVDF membranes. It was observed that the pure water flux increased from 114.68 LMH/bar of the original membrane M0 to 205.02 LMH/bar of the blend membrane M1, and then to 615.88 LMH/bar of the coagulation-bath-regulated membrane MPH9 with a high BSA rejection rate of 90.86%, showing a two-stage jump. The addition of FS-50 promoted the instantaneous phase inversion of the membrane, allowing the blend membrane to exhibit a higher proportion of pore characteristics and stronger permeability. After that, the mechanisms of the membrane phase inversion process affected by the coagulation bath pH were interpreted according to the pH-response characteristics of FS-50 in terms of charge repulsion effect and compressed double-electron layer effect. Furthermore, the cross-sectional morphology and the surface structure of the membrane prepared in acidic and alkaline coagulation baths were significantly affected by the pH of the coagulation bath, exhibiting different features. For one, the porosity of the membranes gradually decreased as the acidity and alkalinity of the coagulation bath increased, and the membrane MPH9 exhibited both maximum surface and overall porosity. For another, the coagulation bath pH did not negatively affect the contact angle, surface roughness and tensile strength of the membranes. Overall, adjusting the dosage of FS-50 and the pH of the coagulation bath is a promising approach to greatly enhance membrane performance.


Assuntos
Fluorcarbonetos , Tensoativos , Estudos Transversais , Concentração de Íons de Hidrogênio , Membranas Artificiais , Polivinil
5.
Chemosphere ; 287(Pt 2): 132092, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34826888

RESUMO

Superhydrophobic nanofibers have received prominent attention owing to their exceptional properties and researchers are focused on developing high-performing MD membranes. Herein, we fabricate superhydrophobic electrospun nanofibrous membranes using polyvinylidene fluoride (PVDF) solutions with silica nanoparticles (0 wt% to 6 wt%) to create multiscale (or hierarchical) surface roughness. For superhydrophobicity, the composite membranes (Si@PVDF) were subjected to a two-step modification that included acid pre-treatment and silanization with fluoroalkylsilane (FAS) compound of low surface energy. The acid pre-treatment enhances the hydroxyl group of SiO2 nanoparticles and create active sites in abundance for silanization. The modified membranes (FAS-Si@PVDF-A) having 6 wt% SiO2 showed excellent wetting resistance with water contact angle (WCA) up to 154.6 ± 2.2°, smaller average pore size of 0.27 ± 0.3 µm, and high liquid entry pressure (LEP) of 143 ± 4 kPa. It was observed, increasing silica content decreased the fiber diameter and average pore size and increased WCA and LEP of modified membranes. The modified superhydrophobic membranes gave stable permeate flux, exhibited strong wetting resistance and excellent salt rejection in vacuum membrane distillation (VMD) test. The optimal FAS-Si@PVDF-A membrane (6 wt% SiO2) of thickness 98 ± 5 µm produced a stable permeate flux of more than 11.5 kg m-2 h-1 and salt rejection as high as 99.9% after 22 h of continuous operation using NaCl solution (3.5 wt%) as feed. Therefore, this modification provided superhydrophobic membranes possessing robust anti-wetting properties with significant permeability and has encouraging application in membrane distillation for desalination.


Assuntos
Nanofibras , Purificação da Água , Destilação , Interações Hidrofóbicas e Hidrofílicas , Membranas Artificiais , Polivinil , Dióxido de Silício , Vácuo
6.
J Hazard Mater ; 422: 126877, 2022 01 15.
Artigo em Inglês | MEDLINE | ID: mdl-34425428

RESUMO

Carbon nitride (CN)/polyvinylidene fluoride (PVDF) photocatalytic composite membrane (PCM) is considered as a promising candidate to improve the anti-fouling characteristic of conventional PVDF membrane and overcome the difficulty encountered during recovery of powder catalyst simultaneously. However, the effects of differently-modified CN on PCM and its mechanism are still unclear. In this study, bulk-CN (BCN), carbon defects CN (CCN), nitrogen defect CN (DCN), mesoporous CN (MCN), and nitrogen-rich CN (NCN) were incorporated into PVDF by phase inversion method. The influence of changes in the physical and chemical properties of CN, including hydrophilic groups, photocatalytic activity, and particle size, on the permeability, anti-fouling characteristic, and photocatalytic self-cleaning activity of CN/PVDF was systematically analyzed. The mechanism of excellent performance of PCM was revealed by experimental test and theoretical calculation. The flux of PCM was significantly improved by increasing the hydrophilic group on modified CN. However, the differences in particle size and interaction between different types of modified CN and PVDF chains endowed the CN/PVDF with different porosity. DCN/PVDF showed high porosity and hydrophilicity, leading to high water flux and rejection rate of 293.6 L (m2 h)-1 and 90.1%, respectively. Compared to pure PVDF, the flux recovery rate of DCN30/PVDF increased by 27.6%, and the irreversible fouling decreased from 36.9% to 9.2%. The modified CN/PVDF showed excellent photocatalytic activity for the removal of cefotaxime (CFX) and E. coli. Owing to the narrow band gap of DCN, large specific surface area, and low photogenerated carrier recombination rate, the CFX removal rate reached 99% in 2 h, and E. coli inactivation achieved 3.7 log within 4 h via DCN30/PVDF.


Assuntos
Escherichia coli , Membranas Artificiais , Polímeros de Fluorcarboneto , Nitrilas , Polivinil
7.
J Hazard Mater ; 421: 126747, 2022 01 05.
Artigo em Inglês | MEDLINE | ID: mdl-34364210

RESUMO

The synthesis of Bi2WO6 and CeO2 photocatalytic nanomaterials exhibit a great ability to photodegrade the antibiotics and shown excellent oxidation of various organic pollutants. Heterostructure 1:1 & 2:1 Bi2WO6/CeO2 nanocomposite was successfully synthesized via the facile sono-dispersion method and exquisite photocatalytic activity. The 0.5 wt% of nanocomposites were well-grafted on PVDF membrane surface via an in-situ polymerization method using polyacrylic acid. The fourier transform infrared (FTIR) spectra demonstrated that the network formation in PVDF induced by the -COOH functional group in acrylic acid. The grafted membrane morphology and strong binding ability over the membranes were validated by scanning electron microscope with energy dispersion (SEM-EDS) and X-ray photoelectron spectroscopy (XPS), respectively. The permeate flux of 49.2 L.m-2 h-1 and 41.65 L.m-2 h were observed for tetracycline and the humic acid solution respectively for 1 wt% of PVP and 0.5 wt% of photocatalytic nanomaterials in PVDF membrane. The tetracycline and humic acid photodegradation rate of 82% and 78% and total resistance of 1.43 × 1010 m-1 and 1.64 × 1010 m-1, 83.5% and 77% flux recovery ratio were observed with N5 membrane. The 2:1 Bi2WO6/CeO2 nanocomposite grafted membrane showed a high permeate flux and better photodegradation ability of organic pollutants in the wastewater.


Assuntos
Substâncias Húmicas , Tetraciclina , Antibacterianos , Catálise , Polivinil
8.
Chemosphere ; 286(Pt 2): 131756, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34365174

RESUMO

MnO2 nanorods with controllable scale were grown in the PVDF-g-PMAA modified membrane to form PVDF-g-PMAA@ MnO2 membrane through the in situ redox reaction of KMnO4 solution, which is confirmed by scanning electron microscopy (SEM) and X-ray energy-dispersion spectroscopy (EDX). The pore size of the membrane decreased with the increase of KMnO4 solution concentration. The thermodynamic stability and the hydrophilicity of the membrane were also enhanced by the MnO2 nanorods. The water flux, bovine serum albumin (BSA)/Lysozyme protein solution flux and rejection, flux recovery, etc. showed effective improvement of the anti-fouling performance of the PVDF-g-PMAA@ MnO2 membrane. More importantly, it can effectively separate BSA from lysozyme, which provided a potential application in the field of biology, food, and other industrial fields for the requirement of separation and purification.


Assuntos
Incrustação Biológica , Nanotubos , Incrustação Biológica/prevenção & controle , Compostos de Manganês , Membranas Artificiais , Óxidos , Ácidos Polimetacrílicos , Polivinil
9.
J Colloid Interface Sci ; 607(Pt 1): 367-377, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34509111

RESUMO

Harmless and breathable flexible humidity sensor has important applications in continuous and real-time detection of human physiological activities. In this work, with hydrophobic poly (vinylidene fluoride) (PVDF) membrane as both the template and substrate and cetyltrimethylammonium bromide as a structure regulator, polyaniline (PANI) was unilaterally deposited on a PVDF microporous membrane to facilely fabricate a single-sided integrated flexible humidity sensor (IFHS). Such IFHS is featured with unique micro/nano structure and good air permeability. Moreover, it exhibits good humidity sensing properties at room temperature including fast response, small hysteresis and stable response even under bending deformation. The flexible sensor could realize non-contact monitoring of human respiration and speaking activities. Unilateral deposition of PANI and good breathability of IFHS avoids direct contact between PANI and human skin, thus averting harms to human and minimizing the deterioration of humidity sensing properties of PANI layer. The simple method is universal to the preparation of single-sided, integrated, breathable, nontoxic and fast response wearable humidity sensors based on PANI and hydrophobic microporous polymer membranes, offering useful references for the construction of advanced flexible sensors.


Assuntos
Nanoestruturas , Dispositivos Eletrônicos Vestíveis , Compostos de Anilina , Humanos , Umidade , Polivinil , Compostos de Vinila
10.
J Colloid Interface Sci ; 607(Pt 1): 711-719, 2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-34530191

RESUMO

Indoor air quality (IAQ) has assumed new significance given the extensive amount of time spent indoor due to the coronavirus pandemic and particulate matter (PM) pollution. Accordingly, the development of window air filters to effectively intercept PM from outdoor air under natural ventilation conditions is an important research topic. However, most existing filters inevitably suffer from the compromise among filtration capability, transparency, and air permeability. In this study, we fabricate a high-performance transparent air filter to improve IAQ via natural ventilation. polyvinylidene fluoride (PVDF) superfine nanofibers of size 20-35 nm are prepared using extremely dilute solution electrospinning; a multi-scale nanofiber structure is then designed. By adjusting the ratio of PVDF superfine nanofibers (SNs) to PVDF coarse fibers (CNs), we balance the structure-performance relationship. Benefiting from the multiscale structural features that include a small pore size (0.72 µm) and high porosity (92.22%), the resulting filters exhibit excellent performance including high interception efficiency (99.92%) for PM0.3, low air resistance (69 Pa), high transparency (∼80%) and stable filtration after 100 h of UV irradiation. This work describes a new strategy for the fabrication of nanofibers with true-nanoscale diameters and the design of high-performance air filters.


Assuntos
Filtros de Ar , Nanofibras , Material Particulado , Polivinil
11.
J Environ Manage ; 304: 114260, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34915386

RESUMO

The polyvinylidene difluoride (PVDF) membrane has received considerable attention as a flexible surface enhanced Raman scattering (SERS) substrate due to its excellent mechanical and physicochemical properties. However, the poor fouling resistance of PVDF membrane due to its intrinsic hydrophobic property limits its practical application. To address this, in this investigation, a SERS imprinted membrane is synthesized based on W18O49/Ag composites. Firstly, to promote hydrophilicity, N-vinyl-2-pyrrolidone (NVP) and triethoxyvinylsilane (VTES) are copolymerized by hydrolysis condensation and linked with engineered polyvinypyrrolidone (PVP) chains exposed on the surface of membrane. Furthermore, W18O49/Ag composites are dispersed on the membrane under the assistance of polydopamine (pDA) to promote the pollution resistance. Subsequently, in order to demonstrate the practical detection property, W18O49/Ag/PVDF membrane is selected as the SERS substrate to synthesize SERS imprinted membrane by precipitation polymerization for the selective detection of L-tyrosine. The characteristic results reveal that the SERS-imprinted membrane exhibits satisfactory hydrophilicity, and it can effectively degrade the pollutant molecules absorbed on its surface under ultraviolet light illumination. It is proved from the detection results that the LOD of WADP-MIMs for L-tyrosine reached 10-9 mol L-1 when the concentration of L-tyrosine changed between 10-3-10-9 mol L-1. The correlation coefficient (R2) is 0.994 and the limit of detection is 10-9 mol L-1. Meanwhile, it can be applied for the selective detection of L-tyrosine in mixture samples. Overall, this study presents a novel approach for the hydrophilic modification and pollution resistance enhancement of PVDF-based SERS imprinted membrane, which can be effectively utilized for the selective detection of practical samples.


Assuntos
Polivinil , Tirosina , Polímeros de Fluorcarboneto , Interações Hidrofóbicas e Hidrofílicas , Análise Espectral Raman
12.
Environ Res ; 204(Pt A): 111943, 2022 03.
Artigo em Inglês | MEDLINE | ID: mdl-34478725

RESUMO

As one of the main pollutants of water pollution, the potential toxicity of heavy metal ions always threatens the safety of human and nature. Therefore, how to effectively remove heavy metal ions has become an important research topic in environmental protection. In the existing research, adsorption method is outstanding from many methods because of its high adsorption efficiency and easy operation. In this study, different generations of hyperbranched polyamide-amine (PAMAM) were grafted onto PVDF membrane to obtain the membrane with high adsorption capacity for heavy metal ions. The structure and physicochemical properties of the membranes were evaluated by means of fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (FE-SEM), element analyzer and X-ray photoelectron spectroscopy (EDX). At the same time, various factors affecting the adsorption process were studied, and it was found that the adsorption behavior of copper ion (Cu2+) on the membrane conformed to the pseudo-first-order kinetic model and Langmuir isotherm model. Moreover, after comparing the adsorption effect of the modified membranes grafted with different generations of PAMAM, it was found that the membrane grafted with the third generation PAMAM had the best adsorption when the solution pH was 5, and its maximum adsorption capacity could reach 153.8 mg/g. After five adsorption-desorption cycles, its adsorption capacity can reach 72.83% of the first test, indicating that it has good recycling performance. The results show that the adsorption membrane has good application potential and research value.


Assuntos
Metais Pesados , Poluentes Químicos da Água , Adsorção , Aminas , Cobre , Polímeros de Fluorcarboneto , Humanos , Concentração de Íons de Hidrogênio , Íons , Cinética , Nylons , Polivinil , Espectroscopia de Infravermelho com Transformada de Fourier , Poluentes Químicos da Água/análise
13.
Sensors (Basel) ; 21(24)2021 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-34960518

RESUMO

Pyroelectrics are a wide class of materials that change their polarization when the system temperature varies. This effect is utilized for a number of different commercial and industrial applications ranging from simple thermal sensors and laser interferometers to water vapor harvesting. Electron paramagnetic resonance (EPR) spectroscopy is a powerful tool for studying the structure and dynamics of materials with unpaired electrons. Since heating accompanies a resonant change of the orientation of electron spins in an external magnetic field, pyroelectrics can be utilized as versatile detectors for so-called indirect detection of the EPR signal. In this work, we investigated three different types of PVDF (polyvinylidene difluoride) standard pyroelectric films with indium tin oxide, Cu/Ni, and Au coatings to determine their sensitivity for detecting EPR signals. All the films were shown to be able to detect the EPR spectra of about 1 µg of a standard stable free radical by heat release. A comparative study based on the calculation of the noise-equivalent power and specific detectivity from experimental spectra showed that the Au coated PVDF film is the most promising active element for measuring the EPR signal. Using the best achieved sensitivity, estimation is given whether this is sufficient for using a PVDF-based pyrodetector for indirectly detecting EPR spectra by recombination heat release or not.


Assuntos
Temperatura Alta , Polivinil , Espectroscopia de Ressonância de Spin Eletrônica , Elétrons , Polímeros de Fluorcarboneto
14.
Diagn Interv Radiol ; 27(6): 786-788, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34792034

RESUMO

Bronchial artery embolization (BAE) is considered the first choice treatment for hemoptysis. To our knowledge no cases of BAE using a recent ethylene vinyl alcohol copolymer agent (Squid) have been previously mentioned. Two cases of BAE for remitting hemoptysis using Squid and polyvinyl alcohol particles are reported in this technical note. The final angiographic control confirmed full exclusion of the target territory in both cases. Both patients felt some chest pain immediately after the embolization, not requiring any medications. No more episodes of hemoptysis occurred in the following 3 months after the procedure.


Assuntos
Artérias Brônquicas , Embolização Terapêutica , Animais , Artérias Brônquicas/diagnóstico por imagem , Decapodiformes , Hemoptise/diagnóstico por imagem , Hemoptise/terapia , Humanos , Álcool de Polivinil , Polivinil , Estudos Retrospectivos , Resultado do Tratamento
15.
Water Sci Technol ; 84(9): 2380-2393, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34810318

RESUMO

Novel polyvinylidene fluoride/TiO2/UiO-66-NH2 (PVDF/TiUN) membranes were produced by the delay phase separation method via introducing the TiO2/UiO-66-NH2 (TiUN) nanocomposite into PVDF casting solution. Interconnection of TiO2 and UiO-66-NH2 improved photocatalysis capacity and endowed PVDF/TiUN membranes with self-cleaning capability. Quantitative measurements showed that, firstly, PVDF/TiUN membranes exhibited improved photodegradation kinetics and efficiency (up to 88.1%) to Rhodamine B (RhB). Secondly, the performances of bovine serum albumin (BSA) rejection and permeation of PVDF/TiUN membranes outperformed those of other check samples, indicating enhanced hydrophilicity. Thirdly, rejection rate of BSA reached a breathtaking 98.14% and flux recovery ratio (FRR) of BSA reached a breathtaking 95.37%. Thus, given their excellent anti-contamination property and separation performance, the PVDF/TiUN membrane is very likely to be a novel water treatment membrane.


Assuntos
Incrustação Biológica , Estruturas Metalorgânicas , Incrustação Biológica/prevenção & controle , Membranas Artificiais , Polivinil , Titânio , Zircônio
16.
Water Sci Technol ; 84(9): 2541-2556, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34810330

RESUMO

Ultrafiltration membranes are widely used for the treatment of papermaking wastewater. The antifouling performance of polyvinylidene fluoride (PVDF) ultrafiltration membranes can be improved by changing the hydrophilicity. Here, a novel amphiphilic copolymer material, PVDF grafted with N-isobutoxy methacrylamide (PVDF-g-IBMA), was prepared using ultraviolet-induced Cu(II)-mediated reversible deactivation radical polymerization. The amphipathic copolymer was used to prepare ultrafiltration membrane via NIPS. The prepared PVDF-g-IBMA ultrafiltration membrane was estimated using 1H NMR, FT-IR, and DSC. The contact angle, casting viscosity, and the permeation performance of the PVDF-g-IBMA ultrafiltration membrane were also determined. The pure water flux, bovine serum albumin removal rate, and pure water flux recovery rate of the PVDF-g-IBMA ultrafiltration membrane were 432.8 L·m-2·h-1, 88.4%, and 90.8%, respectively. Furthermore, for the treatment of actual papermaking wastewater, the chemical oxygen demand and turbidity removal rates of the membrane were 61.5% and 92.8%, respectively. The PVDF-g-IBMA amphiphilic copolymer ultrafiltration membrane exhibited good hydrophilicity and antifouling properties, indicating its potential for treating papermaking wastewater.


Assuntos
Incrustação Biológica , Ultrafiltração , Incrustação Biológica/prevenção & controle , Interações Hidrofóbicas e Hidrofílicas , Membranas Artificiais , Polivinil , Espectroscopia de Infravermelho com Transformada de Fourier , Águas Residuárias
17.
Part Fibre Toxicol ; 18(1): 38, 2021 10 18.
Artigo em Inglês | MEDLINE | ID: mdl-34663357

RESUMO

BACKGROUND: Silver nanoparticles (AgNPs) are widely used in biomedicine due to their strong antimicrobial, antifungal, and antiviral activities. Concerns about their possible negative impacts on human and environmental health directed many researchers towards the assessment of the safety and toxicity of AgNPs in both in vitro and in vivo settings. A growing body of scientific information confirms that the biodistribution of AgNPs and their toxic effects vary depending on the particle size, coating, and dose as well as on the route of administration and duration of exposure. This study aimed to clarify the sex-related differences in the outcomes of oral 28 days repeated dose exposure to AgNPs. METHODS: Wistar rats of both sexes were gavaged daily using low doses (0.1 and 1 mg Ag/kg b.w.) of polyvinylpyrrolidone (PVP)-coated small-sized (10 nm) AgNPs. After exposure, blood and organs of all rats were analysed through biodistribution and accumulation of Ag, whereas the state of the liver and kidneys was evaluated by the levels of reactive oxygen species (ROS) and glutathione (GSH), catalase (CAT) activity, superoxide dismutase (SOD) and glutathione peroxidase (GPx), expression of metallothionein (Mt) genes and levels of Mt proteins. RESULTS: In all animals, changes in oxidative stress markers and blood parameters were observed indicating the toxicity of AgNPs applied orally even at low doses. Sex-related differences were noticed in all assessed parameters. While female rats eliminated AgNPs from the liver and kidneys more efficiently than males when treated with low doses, the opposite was observed for animals treated with higher doses of AgNPs. Female Wistar rats exposed to 1 mg PVP-coated AgNPs/kg b.w. accumulated two to three times more silver in the blood, liver, kidney and hearth than males, while the accumulation in most organs of digestive tract was more than ten times higher compared to males. Oxidative stress responses in the organs of males, except the liver of males treated with high doses, were less intense than in the organs of females. However, both Mt genes and Mt protein expression were significantly reduced after treatment in the liver and kidneys of males, while they remained unchanged in females. CONCLUSIONS: Observed toxicity effects of AgNPs in Wistar rats revealed sex-related differences in response to an oral 28 days repeated exposure.


Assuntos
Nanopartículas Metálicas , Povidona , Animais , Feminino , Masculino , Nanopartículas Metálicas/toxicidade , Polivinil , Povidona/toxicidade , Ratos , Ratos Wistar , Prata/toxicidade , Distribuição Tecidual
18.
Molecules ; 26(19)2021 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-34641513

RESUMO

A study on the headspace volatile organic compounds (VOCs) profile of native populations of Sideritis romana L. and Sidertis montana L., Lamiaceae, from Croatia is reported herein, to elucidate the phytochemical composition of taxa from this plant genus, well-known for traditional use in countries of the Mediterranean and the Balkan region. Headspace solid-phase microextraction (HS-SPME), using divinylbenzene/carboxene/polydimethylsiloxane (DVB/CAR/PDMS) or polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber, coupled with gas chromatography-mass spectrometry (GC-MS) was applied to analyze the dried aerial parts of six native populations in total. Furthermore, principal component analysis (PCA) was conducted on the volatile constituents with an average relative percentage ≥1.0% in at least one of the samples. Clear separation between the two species was obtained using both fiber types. The VOCs profile for all investigated populations was characterized by sesquiterpene hydrocarbons, followed by monoterpene hydrocarbons, except for one population of S. romana, in which monoterpene hydrocarbons predominated. To our knowledge, this is the first report on the VOCs composition of natural populations of S. romana and S. montana from Croatia as well as the first reported HS-SPME/GC-MS analysis of S. romana and S. montana worldwide.


Assuntos
Sideritis/química , Compostos Orgânicos Voláteis/análise , Croácia , Dimetilpolisiloxanos/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Monoterpenos/análise , Compostos Fitoquímicos/análise , Polivinil/química , Análise de Componente Principal , Sesquiterpenos/análise , Microextração em Fase Sólida/instrumentação , Microextração em Fase Sólida/métodos
19.
IET Nanobiotechnol ; 15(4): 427-440, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34694715

RESUMO

The main emphasis herein is on the eco-friendly synthesis and assessment of the antimicrobial potential of silver nanoparticles (AgNPs) and a cytotoxicity study. Silver nanoparticles were synthesised by an extracellular method using bacterial supernatant. Biosynthesised silver nanoparticles were characterised by UV-vis spectroscopy, transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, dynamic light scattering, and zeta potential analysis. The synthesised silver nanoparticles exhibited a characteristic peak at 420 nm. TEM analysis depicted the spherical shape and approximately 20 nm size of nanoparticles. Silver nanoparticles carry a charge of -33.75 mV, which confirms their stability. Biogenic polyvinyl pyrrolidone-coated AgNPs exhibited significant antimicrobial effects against all opportunistic pathogens (Gram-positive and Gram-negative bacteria, and fungi). Silver nanoparticles equally affect the growth of both Gram-positive and Gram-negative bacteria, with a maximum inhibition zone observed at 22 mm and a minimum at 13 mm against Pseudomonas aeruginosa and Fusarium graminearum, respectively. The minimum inhibitory concentration (MIC) of AgNPs against P. aeruginosa and Staphylococcus aureus was recorded at between 15 and 20 µg/ml. Synthesised nanoparticles exhibited a significant synergistic effect in combination with conventional antibiotics. Cytotoxicity estimates using C2C12 skeletal muscle cell line via 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) test and lactate dehydrogenase assay were directly related to the concentration of AgNPs and length of exposure. On the basis of the MTT test, the IC50 of AgNPs for the C2C12 cell line was approximately 5.45 µg/ml concentration after 4 h exposure.


Assuntos
Anti-Infecciosos , Nanopartículas Metálicas , Antibacterianos/farmacologia , Anti-Infecciosos/farmacologia , Bacillaceae , Escherichia coli , Fusarium , Bactérias Gram-Negativas , Bactérias Gram-Positivas , Nanopartículas Metálicas/toxicidade , Testes de Sensibilidade Microbiana , Polivinil , Prata , Espectroscopia de Infravermelho com Transformada de Fourier
20.
Artigo em Russo | MEDLINE | ID: mdl-34714007

RESUMO

Chronic subdural hematomas (CSH) usually require surgical evacuation via a burr hole or craniotomy. Certain incidence of recurrent postoperative CSH is known. Middle meningeal artery (MMA) embolization has been described as an alternative surgery for new or recurrent CSH or as a preventive measure to reduce the risk of postoperative recurrence. The authors report successful MMA embolization with 2 non-adhesive embolic agents of various viscosities (SQUID 12 and SQUID 18, Balt USA, Irvine, CA, USA) for recurrent postoperative CSH in a 44-year-old woman.


Assuntos
Embolização Terapêutica , Hematoma Subdural Crônico , Adulto , Feminino , Hematoma Subdural Crônico/terapia , Humanos , Artérias Meníngeas , Polivinil , Viscosidade
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