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1.
Sci Rep ; 12(1): 13479, 2022 Aug 05.
Artículo en Inglés | MEDLINE | ID: mdl-35931720

RESUMEN

The relapsing fever agent Borrelia hermsii is transmitted by the tick Ornithodoros hermsi. To study the B. hermsii-tick interactions required for pathogen acquisition and transmission we developed an artificial membrane feeding system for O. hermsi nymphs and adults that results in a high percentage of engorgement. This system provides the nutritional requirements necessary for the tick to develop, mate, and produce viable eggs. By inoculating the blood with B. hermsii, we were able to obtain infected ticks for quantitative studies on pathogen acquisition and persistence. These ticks subsequently transmitted the spirochetes to mice, validating this system for both acquisition and transmission studies. Using this feeding method, a mutant of the antigenic variation locus of B. hermsii (Vmp-) that is incapable of persisting in mice was acquired by ticks at equivalent densities as the wild-type. Furthermore, Vmp is not required for persistence in the tick, as the mutant and wild-type strains are maintained at similar numbers after ecdysis and subsequent feeding. These results support the theory that Vmp is an adaptation for mammalian infection but unnecessary for survival within the tick. Interestingly, B. hermsii numbers severely declined after acquisition, though these ticks still transmitted the infection to mice. This procedure reduces animal use and provides a safe, highly controlled and well-contained alternative method for feeding and maintaining O. hermsi colonies. Importantly, this system permits quantitative studies with B. hermsii strains through ingestion during the blood meal, and thus more closely recapitulates pathogen acquisition in nature than other artificial systems.


Asunto(s)
Borrelia , Ornithodoros , Fiebre Recurrente , Spirochaeta , Animales , Borrelia/genética , Mamíferos , Membranas Artificiales , Ratones
2.
Anal Chim Acta ; 1222: 339986, 2022 Aug 22.
Artículo en Inglés | MEDLINE | ID: mdl-35934419

RESUMEN

Two modes of electromembrane extraction (EME) were evaluated in this work, one using deep eutectic solvents (DESs) as liquid membrane, and another was gel electromembrane extraction (G-EME) based on solid agarose membrane. Both EME modes have eliminated organic solvents and are recognized as green strategies. Unlike classic EME in which polypropylene membrane and organic extracting solvents play an essential role in the extraction process, new modes of EME are based on biodegradable membranes and aqueous extracting solutions. Approaches of EME based on the new designs follow the green chemistry principles. Each mode of EME was evaluated for the determination of polar and non-polar bases drugs from human urine samples using high-performance liquid chromatography (HPLC) equipped with a diode array detector (DAD). EME using DES A was suitable for determining polar and non-polar bases drugs in a large polarity window. While extraction recoveries for all six drugs studied by G-EME were lower than EME using DES A. Comparing the two EME modes shows similar results in the analytical figures of merit. However, differences in extraction recoveries of the drugs by two EME modes were observed which is related to the difference in membranes structure. Our findings indicate that the differences between membranes properties used in two EME modes, including the permeability, hydrophilicity, hydrophobicity, and variety of interactions, are influencer factors on extraction efficiency. The two EME modes provided good linearity in the ranges of 16-100 and 19-100 µg. L-1 for G-EME and EME using DES A, respectively with (r2 > 0.993). Also, the detection limits (LODs) were 19-32 and 19-29 µg. L-1 for G-EME and EME using DES A, respectively.


Asunto(s)
Disolventes Eutécticos Profundos , Membranas Artificiales , Cromatografía Líquida de Alta Presión , Humanos , Sefarosa/química , Solventes/química
3.
Int J Mol Sci ; 23(13)2022 Jun 29.
Artículo en Inglés | MEDLINE | ID: mdl-35806220

RESUMEN

The effect of the modification of the polyvinyl alcohol (PVA) selective layer of thin film composite (TFC) membranes by aluminosilicate (Al2O3·SiO2) nanoparticles on the structure and pervaporation performance was studied. For the first time, PVA-Al2O3·SiO2/polyacrylonitrile (PAN) thin film nanocomposite (TFN) membranes for pervaporation separation of ethanol/water mixture were developed via the formation of the selective layer in dynamic mode. Selective layers of PVA/PAN and PVA-Al2O3·SiO2/PAN membranes were formed via filtration of PVA aqueous solutions or PVA-Al2O3·SiO2 aqueous dispersions through the ultrafiltration PAN membrane for 10 min at 0.3 MPa in dead-end mode. Average particle size and zeta potential of aluminosilicate nanoparticles in PVA aqueous solution were analyzed using the dynamic light scattering technique. Structure and surface properties of membranes were studied using scanning electron microscopy (SEM), atomic force microscopy (AFM) and water contact angle measurements. Membrane performance was investigated in pervaporation dehydration of ethanol/water mixtures in the broad concentration range. It was found that flux of TFN membranes decreased with addition of Al2O3·SiO2 nanoparticles into the selective layer due to the increase in selective layer thickness. However, ethanol/water separation factor of TFN membranes was found to be significantly higher compared to the reference TFC membrane in the whole range of studied ethanol/water feed mixtures with different concentrations, which is attributed to the increase in membrane hydrophilicity. It was found that developed PVA-Al2O3·SiO2/PAN TFN membranes were more stable in the dehydration of ethanol in the whole range of investigated concentrations as well as at different temperatures of the feed mixtures (25 °C, 35 °C, 50 °C) compared to the reference membrane which is due to the additional cross-linking of the selective layer by formation hydrogen and donor-acceptor bonds between aluminosilicate nanoparticles and PVA macromolecules.


Asunto(s)
Nanopartículas , Alcohol Polivinílico , Resinas Acrílicas , Silicatos de Aluminio , Deshidratación , Etanol/química , Humanos , Membranas Artificiales , Alcohol Polivinílico/química , Dióxido de Silicio , Agua/química
4.
Rev Sci Instrum ; 93(6): 064104, 2022 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-35778037

RESUMEN

The ion transport measurements using various ion-exchange membranes (IEMs) face several challenges, including controllability, reproducibility, reliability, and accuracy. This is due to the manual filling of the solutions in two different reservoirs in a typical diffusion cell experiment with a random flow rate, which results in the diffusion through the IEM even before turning on the data acquisition system as reported so far. Here, we report the design and development of an automated experimental setup for ion transport measurements using IEMs. The experimental setup has been calibrated and validated by performing ion transport measurements using a standard nanoporous polycarbonate membrane. We hope that the present work will provide a standard tool for realizing reliable ion transport measurements using ion-exchange membranes and can be extended to study other membranes of various pore densities, shapes, and sizes.


Asunto(s)
Membranas Artificiales , Difusión , Intercambio Iónico , Transporte Iónico , Reproducibilidad de los Resultados
5.
Artículo en Inglés | MEDLINE | ID: mdl-35830314

RESUMEN

This study clinically and histologically evaluated the new bone formation and soft tissue changes when an autogenous tooth-derived mineralized dentin matrix (DDM) graft covered with a free gingival graft (FGG) was used for alveolar ridge preservation, as compared to spontaneous healing. Using a split-mouth protocol, 14 consecutive patients who required two extractions of a single-rooted tooth in the maxillary arch were enrolled. In each patient, one extraction site was treated with DDM and FGG (test group), while the other extraction site was covered with FGG and healed spontaneously (control group). In both test and control sites, implant placement was performed after a 16-week healing period. Compared to baseline (immediately after tooth extraction), both treatments yielded statistically significant differences in some clinical parameters and in the bone micro-architecture within the augmented sites. However, the use of DDM with the FGG created greater new vital bone formation, more newly formed bone, and fewer dimensional tissue changes than spontaneous healing with FGG.


Asunto(s)
Aumento de la Cresta Alveolar , Alveolo Dental , Proceso Alveolar/patología , Proceso Alveolar/cirugía , Aumento de la Cresta Alveolar/métodos , Trasplante Óseo/métodos , Dentina , Humanos , Membranas Artificiales , Extracción Dental/métodos , Alveolo Dental/patología , Alveolo Dental/cirugía
6.
Int J Periodontics Restorative Dent ; 42(4): e113-e120, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35830318

RESUMEN

This study presents a one-stage technique for horizontal guided bone regeneration and transmucosal implant placement in the presence of hard and soft tissue defects. The proposed technique uses autologous bone particles, deproteinized bovine bone matrix, collagen membranes, and concentrated growth factor membranes to create a multilayer barrier and enhance tissue regeneration. Four patients were treated with a total of seven implants. Digital analyses of intraoral scan data taken at baseline and at 6 months postsurgery showed a mean increase in tissue volume of 157.4 mm3. The patient satisfaction was high, and no complications were observed.


Asunto(s)
Implantes Dentales , Animales , Matriz Ósea/trasplante , Regeneración Ósea , Bovinos , Colágeno/uso terapéutico , Implantación Dental Endoósea/métodos , Regeneración Tisular Guiada Periodontal/métodos , Humanos , Membranas Artificiales , Cicatrización de Heridas
7.
Artículo en Inglés | MEDLINE | ID: mdl-35805879

RESUMEN

Forward osmosis (FO) is an evolving membrane separation technology for water treatment and reclamation. However, FO water treatment technology is limited by factors such as concentration polarization, membrane fouling, and reverse solute flux. Therefore, it is of a great importance to prepare an efficient high-density porous membrane and to select an appropriate draw solute to reduce concentration polarization, membrane fouling, and reverse solute flux. This review aims to present a thorough evaluation of the advancement of different draw solutes and membranes with their effects on FO performance. NaCl is still widely used in a large number of studies, and several general draw solutes, such as organic-based and inorganic-based, are selected based on their osmotic pressure and water solubility. The selection criteria for reusable solutes, such as heat-recovered gaseous draw, magnetic field-recovered MNPs, and electrically or thermally-responsive hydrogel are primarily based on their industrial efficiency and energy requirements. CA membranes are resistant to chlorine degradation and are hydrophilic, while TFC/TFN exhibit a high inhibition of bio-adhesion and hydrolysis. AQPs are emerging membranes, due to proteins with complete retention capacity. Moreover, the development of the hybrid system combining FO with other energy or water treatment technologies is crucial to the sustainability of FO.


Asunto(s)
Membranas Artificiales , Purificación del Agua , Ósmosis , Cloruro de Sodio , Soluciones , Aguas Residuales
8.
Environ Sci Technol ; 56(15): 10954-10962, 2022 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-35819002

RESUMEN

To enhance the use of nanofiltration in the production of quality drinking water, particularly through the efficient removal of micropollutants yet still preserving essential minerals, the targeted nanofiltration membranes (NFMs) are required to have small pore dimensions coupled with a high, net-negative charge density. Herein, after the formation of a separation layer using piperazine interfacially polymerized with trimesoyl chloride, the exploitation of residual amine groups was systematically investigated by different diacyl chlorides in an organic milieu, which caused the upper part of the final separation layer to be denser and highly negatively charged. Hence, this protocol offers a novel means to fabricate NFMs simultaneously endowed with a low molecular cutoff (MWCO) of 145-238 Da and a reduced rejection of MgCl2 (48%-80%) as well as a competitive water permeance. Those features are ideally applicable to the goal of removing small micropollutants while preserving mineral ions, as needed for the energy-efficient production of safe, quality drinking water. Furthermore, an attempt was made to correlate MWCO with MgCl2 rejection, which provides some insights on the nexus of the electrostatic effects constrained by size exclusion. The significance of residual amine groups and the modification environment was unveiled, and this method paves a new avenue for designing functional NFMs.


Asunto(s)
Agua Potable , Nylons , Aminas , Cationes Bivalentes , Membranas Artificiales
9.
Commun Biol ; 5(1): 745, 2022 Jul 25.
Artículo en Inglés | MEDLINE | ID: mdl-35879398

RESUMEN

Extracellular mitochondria are present and act as non-cell-autonomous signals to support energetic homeostasis. While mitochondria allograft is a promising approach in rescuing neurons, glia, and vascular cells in CNS injury and disease, there are profound limitations in cellular uptake of mitochondria together with the efficacy. Here, we modified mitochondria by coating them with cationic DOTAP mixed with DOPE via a modified inverted emulsion method to improve mitochondrial transfer and efficacy. We initially optimized the method using control microbeads and liposomes followed by using mitochondria isolated from intact cerebral cortex of male adult C57BL/6J mice. After the coating process, FACS analysis indicated that approximately 86% of mitochondria were covered by DOTAP/DOPE membrane. Moreover, the artificial membrane-coated mitochondria (AM-mito) shifted the zeta-potential toward positive surface charge, confirming successful coating of isolated mitochondria. Mitochondrial proteins (TOM40, ATP5a, ACADM, HSP60, COX IV) and membrane potentials were well maintained in AM-mito. Importantly, the coating improved mitochondrial internalization and neuroprotection in cultured neurons. Furthermore, intravenous infusion of AM-mito immediately after focal cerebral ischemia-reperfusion amplified cerebroprotection in vivo. Collectively, these findings indicate that mitochondrial surface coating with artificial lipid membrane is feasible and may improve the therapeutic efficacy of mitochondria allograft.


Asunto(s)
Membranas Artificiales , Mitocondrias , Animales , Lípidos , Liposomas/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Mitocondrias/metabolismo
10.
Int J Mol Sci ; 23(14)2022 Jul 19.
Artículo en Inglés | MEDLINE | ID: mdl-35887303

RESUMEN

Present research was directed towards the development of new high-performance and cost-effective polysulfone membranes (PSFQ) by introducing ionic liquids (ILs-Cyphos 101 IL and Aliquat 336) into their matrix. Variation of ILs was performed with the aim to find the one that brings new properties and improves the functionality and selectivity of PSFQ membranes in ultrafiltration processes. Based on the obtained results of the rheological study, we established the compatibility of compounds and optimal content of the used ILs, namely 3 wt% and 15 wt% Cyphos 101 IL and compositions varying between 3 and 15 wt % Aliquat 336. Results indicated that the ILs acted as plasticizers when they were added to the system, a helpful aspect in processing membranes used in water decontamination. The efficiency and performance of the membranes were evaluated by their use in the treatment of diclofenac (DCF)-containing waters. Membranes obtained from PSFQ/Aliquat 336 solution containing 15 wt% IL exhibited a 97% removal degree of DCF in the treatment process of 50 mL solution containing 3 mg/L DCF. The separation efficiency was kept constant for four filtration/cleaning cycles. The results indicated an improvement in membrane performance as the amount of IL in their structure increased, which confirms the potential for application in water treatment processes.


Asunto(s)
Líquidos Iónicos , Líquidos Iónicos/química , Membranas , Membranas Artificiales
11.
Carbohydr Polym ; 294: 119756, 2022 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-35868783

RESUMEN

Nanofibrous membrane have great potential in the field of water purification due to the high porosity and large specific surface area. Herein, a dual layers nanofibrous membrane was prepared by combining an active layer containing carbon nanotubes (CNTs) with a porous chitosan (CS)/polyvinylpyrrolidone (PVP)/polyvinyl alcohol (PVA) nanofibrous support layer via electrospinning-electrospray technique for highly efficient heavy metal and organic pollutants removal. Incorporating CNTs into the active layer offered additional nanochannels which significantly enhanced pure water permeate flux (1533.26 L·m-2·h-1) and heavy metal ions/dyes rejection (Cu2+ 95.68 %, Ni2+ 93.86 %, Cd2+ 88.52 %, Pb2+ 80.41 %, malachite green 87.20 %, methylene blue 76.33 %, and crystal violet 63.39 %). The optimal membranes were formed with a thickness of 20 µm and a roughness of 142 nm while still showing good perm-selectivity compared with commercial PVDF membrane. Moreover, the constructed membrane exhibited good antifouling property and long-term stability during filtration process. This work provides a new strategy to fabricate advanced separation membranes for water treatment.


Asunto(s)
Quitosano , Metales Pesados , Nanofibras , Nanotubos de Carbono , Purificación del Agua , Quitosano/química , Membranas Artificiales , Nanofibras/química , Alcohol Polivinílico/química , Povidona , Purificación del Agua/métodos
12.
Biomed Res Int ; 2022: 7742687, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35872861

RESUMEN

This study is aimed at performing a systematic review and a network meta-analysis of the effects of several membranes on vertical bone regeneration and clinical complications in guided bone regeneration (GBR) or guided tissue regeneration (GTR). We compared the effects of the following membranes: high-density polytetrafluoroethylene (d-PTFE), expanded polytetrafluoroethylene (e-PTFE), crosslinked collagen membrane (CCM), noncrosslinked collagen membrane (CM), titanium mesh (TM), titanium mesh plus noncrosslinked (TM + CM), titanium mesh plus crosslinked (TM + CCM), titanium-reinforced d-PTFE, titanium-reinforced e-PTFE, polylactic acid (PLA), polyethylene glycol (PEG), and polylactic acid 910 (PLA910). Using the PICOS principles to help determine inclusion criteria, articles are collected using PubMed, Web of Science, and other databases. Assess the risk of deviation and the quality of evidence using the Cochrane Evaluation Manual, and GRADE. 27 articles were finally included. 19 articles were included in a network meta-analysis with vertical bone increment as an outcome measure. The network meta-analysis includes network diagrams, paired-comparison forest diagrams, funnel diagrams, surface under the cumulative ranking curve (SUCRA) diagrams, and sensitivity analysis diagrams. SUCRA indicated that titanium-reinforced d-PTFE exhibited the highest vertical bone increment effect. Meanwhile, we analyzed the complications of 19 studies and found that soft tissue injury and membrane exposure were the most common complications.


Asunto(s)
Regeneración Tisular Guiada Periodontal , Titanio , Regeneración Ósea , Colágeno , Membranas Artificiales , Metaanálisis en Red , Politetrafluoroetileno
13.
Environ Sci Technol ; 56(14): 10339-10348, 2022 07 19.
Artículo en Inglés | MEDLINE | ID: mdl-35786926

RESUMEN

Biofouling in anaerobic membrane bioreactors (AnMBRs) has not been studied widely. Moreover, the effect of membrane surface properties on biofilm formation beyond initial deposition is controversial. We investigated biofouling with polyvinyldifluoride, polyacrylonitrile, and zwitterion-modified polyethersulfone ultrafiltration membranes having different properties during 72 h filtration using natural anaerobes isolated from AnMBR and analyzed biofilm characteristics by physicochemical and molecular techniques. A decrease in membrane performance was positively correlated with biofilm formation on polyvinyldifluoride and polyacrylonitrile membranes, and as expected, physical cleaning effectively mitigated biofilm on hydrophilic and low-roughness membranes. Surprisingly, while the biofilm on the hydrophilic and low-surface roughness zwitterion-modified membrane was significantly impaired, the impact on transmembrane pressure was the highest. This was ascribed to the formation of a soft compressible thin biofilm with high hydraulic resistance, and internal clogging and pore blocking due to high pore-size distribution. Anaerobe community analysis demonstrated some selection between the bulk and biofilm anaerobes and differences in the relative abundance of the dominant anaerobes among the membranes. However, correlation analyses revealed that all membrane properties studied affected microbial communities' composition, highlighting the system's complexity. Overall, our findings indicate that the membrane properties can affect biofilm formation and the anaerobic microbial population but not necessarily alleviate biofouling.


Asunto(s)
Incrustaciones Biológicas , Anaerobiosis , Bacterias Anaerobias , Biopelículas , Reactores Biológicos , Membranas Artificiales , Ultrafiltración/métodos
14.
Environ Sci Technol ; 56(14): 10279-10288, 2022 07 19.
Artículo en Inglés | MEDLINE | ID: mdl-35802136

RESUMEN

The permeance and selectivity of a reverse osmosis (RO) membrane are governed by its ultrathin polyamide film, yet the growth of this critical film during interfacial polymerization (IP) has not been fully understood. This study investigates the evolution of a polyamide nanofilm at the aqueous/organic interface over time. Despite its thickness remaining largely constant (∼15 nm) for the IP reaction time ranging from 0.5 to 60 min, the density of the polyamide nanofilm increased from 1.25 to 1.36 g cm-3 due to the continued reaction between diffused m-phenylenediamine and dangling acyl chloride groups within the formed polyamide film. This continued growth of the polyamide nanofilm led to a simultaneous increase in its crosslinking degree (from 50.1 to 94.3%) and the healing of nanosized defects, resulting in a greatly enhanced rejection of 99.2% for NaCl without sacrificing water permeance. Using humic acid as a molecular probe for sealing membrane defects, the relative contributions of the increased crosslinking and reduced defects toward better membrane selectivity were resolved, which supports our conceptual model involving both enhanced size exclusion and healed defects. The fundamental insights into the growth mechanisms and the structure-property relationship of the polyamide nanofilm provide crucial guidance for the further development and optimization of high-performance RO membranes.


Asunto(s)
Nylons , Agua , Filtración/métodos , Membranas Artificiales , Polimerizacion
15.
Folia Med (Plovdiv) ; 64(1): 13-20, 2022 Feb 28.
Artículo en Inglés | MEDLINE | ID: mdl-35851902

RESUMEN

Here we review the knowledge on the local biological immunological response (formation of "pseudo periosteum" of the host) to two types of nonresorbable membranes used in the horizontal and vertical alveolar ridge augmentation: the titanium-reinforced polytetrafluoroethylene membrane and the titanium mesh membrane. A literature search was conducted including available in vitro, in vivo, and clinical studies on cellular and molecular immunological response to these two types of nonresorbable membranes, in particular the formation of "pseudo periosteum".


Asunto(s)
Regeneración Tisular Guiada Periodontal , Periostio , Regeneración Ósea/fisiología , Membranas Artificiales , Periostio/cirugía , Politetrafluoroetileno , Titanio
16.
J Chromatogr A ; 1676: 463271, 2022 Aug 02.
Artículo en Inglés | MEDLINE | ID: mdl-35779390

RESUMEN

In this study, the retention on three types of columns, an immobilized artificial membrane (IAM), a cholesterol-bonded and an octadecyl (C18) column, was applied for the prediction of skin permeability. The first two columns are biomimicking ones, which have certain components of the skin bound to the stationary phase, and were applied in HPLC, while the sub-2 µm C18 column was studied in UHPLC because of its fast features. Fifty-eight compounds were analyzed applying different mobile-phase compositions, with varying percentages of organic modifier on every column, to extrapolate the retention factor to a theoretically purely aqueous mobile phase (log kw). The retention factors, along with two sets of theoretical molecular descriptors, were used to model the skin permeability coefficient (log Kp) using multiple linear regression (MLR) and partial least squares (PLS) regression modelling. Although the retention factors (log k) on the IAM column showed a better correlation with the skin permeability, the overall best model was obtained by applying a stepwise MLR approach on the UHPLC parameters combined with some theoretical descriptors. This model showed a good fit, and on top has potential to accurately predict skin permeability values. Furthermore, the UHPLC method has the advantage of being fast and can thus be classified as a high-throughput approach.


Asunto(s)
Colesterol , Membranas Artificiales , Cromatografía Líquida de Alta Presión/métodos , Permeabilidad , Preparaciones Farmacéuticas
17.
J Am Chem Soc ; 144(30): 13764-13772, 2022 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-35866599

RESUMEN

Introducing alien intercalations to sub-nanometer scale nanochannels is one desirable strategy to optimize the ion transportation of two-dimensional nanomaterial membranes for improving osmotic energy harvest (OEH). Diverse intercalating agents have been previously utilized to realize this goal in OEH, but with modest performance, complex operations, and physicochemical uncertainty gain. Here, we employ the self-exfoliation behavior of oxidative fragments (OFs) from graphene oxide basal plane under an alkaline environment to encapsulate detached OFs in nanochannels for breaking a trade-off between permeability and selectivity, boosting power density from 1.8 to 4.9 W m-2 with a cation selectivity of 0.9 and revealing a negligible decline in power density and trade-off during a long-term operation test (∼168 h). The strategy of membrane design, employing the intrinsically self-exfoliated OFs to decorate the nanochannels, provides an alternative and facile approach for ion separation, OEH, and other nano-fluidic applications.


Asunto(s)
Grafito , Membranas Artificiales , Ósmosis , Permeabilidad
18.
J Am Soc Mass Spectrom ; 33(8): 1510-1517, 2022 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-35866646

RESUMEN

Naphthenic acids comprise one of the most toxic compounds of the produced water released from offshore oil platforms. Therefore, developing and applying faster, simpler, and more efficient analytical methods for analyzing naphthenic acids are urgently needed. Electromembrane extraction (EME) uses the electrokinetic migration of target ions through a porous membrane. Herein, the EME method was applied to extract naphthenic acids from produced water. The EME method was optimized, and the optimal conditions encompassed decanol as the organic solvent, the sample with pH 10.0, 5 min of extraction at 200 V, and the ratio 4:1 (borate buffer/matrix, v/v). Electrochemical impedance spectroscopy confirmed charged species' migration from produced water through the EME. Subsequently, all extracts were analyzed by ultra-high-resolution mass spectrometry. The EME efficiency was assessed by comparing the extraction results to the liquid-liquid extraction (LLE) method results. Analytical results showed good linearity for both solvent and matrix curves (R2 > 0.98). Low detection limits ranged from 0.10 to 0.13 µg mL-1 and quantification limits from 0.36 to 0.45 µg mL-1. Precision and accuracy values ranged from -13.3% to 16.5%. These values fit the proposed method, demonstrating that the EME was more efficient than LLE in naphthenic acid extraction. The EME method preferably extracted aromatic compounds with double-bond equivalence from 6 to 8. The EME coupled with ultra-high-resolution mass spectrometry was demonstrated as a promising analytical approach to naphthenic acid extraction as an efficient and more environmentally friendly alternative to conventional extraction methods.


Asunto(s)
Membranas Artificiales , Agua , Ácidos Carboxílicos , Espectrometría de Masas , Solventes/química , Agua/química
19.
Molecules ; 27(11)2022 Jun 02.
Artículo en Inglés | MEDLINE | ID: mdl-35684512

RESUMEN

Anion Exchange Membrane (AEM) fuel cells have attracted growing interest, due to their encouraging advantages, including high power density and relatively low cost. AEM is a polymer matrix, which conducts hydroxide (OH-) ions, prevents physical contact of electrodes, and has positively charged head groups (mainly quaternary ammonium (QA) groups), covalently bound to the polymer backbone. The chemical instability of the quaternary ammonium (QA)-based head groups, at alkaline pH and elevated temperature, is a significant threshold in AEMFC technology. This review work aims to introduce recent studies on the chemical stability of various QA-based head groups and transportation of OH- ions in AEMFC, via modeling and simulation techniques, at different scales. It starts by introducing the fundamental theories behind AEM-based fuel-cell technology. In the main body of this review, we present selected computational studies that deal with the effects of various parameters on AEMs, via a variety of multi-length and multi-time-scale modeling and simulation methods. Such methods include electronic structure calculations via the quantum Density Functional Theory (DFT), ab initio, classical all-atom Molecular Dynamics (MD) simulations, and coarse-grained MD simulations. The explored processing and structural parameters include temperature, hydration levels, several QA-based head groups, various types of QA-based head groups and backbones, etc. Nowadays, many methods and software packages for molecular and materials modeling are available. Applications of such methods may help to understand the transportation mechanisms of OH- ions, the chemical stability of functional head groups, and many other relevant properties, leading to a performance-based molecular and structure design as well as, ultimately, improved AEM-based fuel cell performances. This contribution aims to introduce those molecular modeling methods and their recent applications to the AEM-based fuel cells research community.


Asunto(s)
Compuestos de Amonio , Membranas Artificiales , Electrodos , Polímeros/química , Temperatura
20.
Carbohydr Polym ; 291: 119601, 2022 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-35698404

RESUMEN

Membranes are the dominant material for seawater desalination and clean-water harvesting, which are commonly composed of synthetic polymers, showing low hydrophilicity and environmental hazard. Herein, we developed a low-cost, intrinsically green, superhigh-water flux Janus cellulose membrane (CEM) via a facile cellulase etching strategy. Coating cellulase on the single surface of cellulose membrane (such as top surface), triggers effective etching on its top section rather than bottom section, which architects an asymmetric-pore structure of the Janus CEM including porous top-and dense bottom-layer. Such distinction endows the Janus CEM with an unprecedented high-water flux of 135.75 LMH and a low salt-water ratio of 0.29 g·L-1 for 1 M NaCl solution, which is 17-time higher and 62-time lower than that of the pristine CEM. Our Janus CEM enables a promising participant for the advanced membrane materials toward versatile separation engineering.


Asunto(s)
Celulasas , Purificación del Agua , Celulosa/química , Humanos , Membranas Artificiales , Ósmosis , Agua/química
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