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1.
Public Health Nurs ; 2024 Jun 09.
Artigo em Inglês | MEDLINE | ID: mdl-38853282

RESUMO

BACKGROUND: Postpartum depression is among the most common complications associated with child-bearing having a period prevalence rate of 17%. Despite the prevalence of postpartum depression, recognition and treatment remains low. METHODS: This paper examines the predictors of help-seeking behavior among a sample (N = 326) of postpartum women. A cross-sectional survey was deployed, and participants were recruited via social media through snowball and convenient sampling techniques. RESULTS: Binary logistic regression was used to analyze the data. Results indicate the severity of depression and favorable attitudes toward help-seeking were predictors of help-seeking behavior among postpartum women in this sample. DISCUSSION/CONCLUSION: This study has implications for healthcare workers, including the allied health professions. Access to treatment is, in part, influenced by a woman's ability to ask for help from health professionals. Social workers and nurses have an opportunity to educate and discuss postpartum mental health and improve treatment seeking.

2.
Br J Haematol ; 194(1): 53-60, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34114218

RESUMO

Measurement of BCR activator of RhoGEF and GTPase -ABL proto-oncogene 1, non-receptor tyrosine kinase (BCR-ABL1) mRNA levels by reverse transcription quantitative polymerase chain reaction (RTqPCR) has been critical to treatment protocols and clinical trials in chronic myeloid leukaemia; however, interlaboratory variation remains a significant issue. Reverse transcriptase droplet digital PCR (RTddPCR) has shown potential to improve testing but a large-scale interlaboratory study is required to definitively establish this. In the present study, 10 BCR-ABL1-positive samples with levels ranging from molecular response (MR)1·0 -MR5·0 were tested by 23 laboratories using RTddPCR with the QXDX BCR-ABL %IS kit. A subset of participants tested the samples using RTqPCR. All 23 participants using RTddPCR detected BCR-ABL1 in all samples to MR4·0 . Detection rates for deep-response samples were 95·7% at MR4·5 , 78·3% at MR4·7 and 87·0% at MR5·0 . Interlaboratory coefficient of variation was indirectly proportional to BCR-ABL1 level ranging from 29·3% to 69·0%. Linearity ranged from 0·9330 to 1·000 (average 0·9936). When results were compared for the 11 participants who performed both RTddPCR and RTqPCR, RTddPCR showed a similar limit of detection to RTqPCR with reduced interlaboratory variation and better assay linearity. The ability to detect deep responses with RTddPCR, matched with an improved linearity and reduced interlaboratory variation will allow improved patient management, and is of particular importance for future clinical trials focussed on achieving and maintaining treatment-free remission.


Assuntos
Proteínas de Fusão bcr-abl/sangue , Ensaio de Proficiência Laboratorial , Leucemia Mielogênica Crônica BCR-ABL Positiva/sangue , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Ásia , Biomarcadores Tumorais/sangue , Europa (Continente) , Células HL-60/química , Humanos , Células K562/química , Laboratórios Clínicos , Modelos Lineares , América do Norte , Kit de Reagentes para Diagnóstico , Reprodutibilidade dos Testes
3.
Phys Chem Chem Phys ; 22(11): 6478, 2020 Mar 18.
Artigo em Inglês | MEDLINE | ID: mdl-32129432

RESUMO

Correction for 'Isomer-specific cryogenic ion vibrational spectroscopy of the D2 tagged Cs+(HNO3)(H2O)n=0-2 complexes: ion-driven enhancement of the acidic H-bond to water' by Sayoni Mitra et al., Phys. Chem. Chem. Phys., 2020, DOI: 10.1039/c9cp06689f.

4.
Phys Chem Chem Phys ; 22(8): 4501-4507, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32068217

RESUMO

We report how the binary HNO3(H2O) interaction is modified upon complexation with a nearby Cs+ ion. Isomer-selective IR photodissociation spectra of the D2-tagged, ternary Cs+(HNO3)H2O cation confirms that two structural isomers are generated in the cryogenic ion source. In one of these, both HNO3 and H2O are directly coordinated to the ion, while in the other, the water molecule is attached to the OH group of the acid, which in turn binds to Cs+ with its -NO2 group. The acidic OH stretching fundamental in the latter isomer displays a ∼300 cm-1 red-shift relative to that in the neutral H-bonded van der Waals complex, HNO3(H2O). This behavior is analyzed with the aid of electronic structure calculations and discussed in the context of the increased effective acidity of HNO3 in the presence of the cation.

5.
J Phys Chem A ; 124(15): 2991-3001, 2020 Apr 16.
Artigo em Inglês | MEDLINE | ID: mdl-32162519

RESUMO

The gas-phase vibrational spectrum of the isolated iodide-water cluster ion (I-·H2O), first reported in 1996, presents one of the most difficult, long-standing spectroscopic puzzles involving ion microhydration. Although the spectra of the smaller halides are well described in the context of an asymmetrical ground-state structure in which only one OH group is hydrogen-bonded to the ion, the I-·H2O spectrum displays multiplet structures with partially resolved rotational patterns that are additionally influenced by quantum nuclear spin statistics. In this study, this complex behavior is unraveled with a combination of experimental methods, including ion preparation in a temperature-controlled ion trap and spectral simplification through applications of tag-free, two-color IR-IR double-resonance spectroscopy. Analysis of the double-resonance spectra reveals a vibrational ground-state tunneling splitting of about 20 cm-1, which is on the same order as the spacing between the peaks that comprise the multiplet structure. These findings are further supported by the results obtained from a fully coupled, six-dimensional calculation of the vibrational spectrum. The underlying level structure can then be understood as a consequence of experimentally measurable, vibrational mode-dependent tunneling splittings (which, in the case of the ground vibrational state, is comparable to the rotational energy spacing between levels with Ka = 0 and 1), as well as Fermi resonance interactions. The latter include the hydrogen-bonded OH stretches and combination bands that involve the HOH bend overtones and soft-mode excitations of frustrated translation and rotation displacements of the water molecule relative to the ion. These anharmonic couplings yield closely spaced bands that are activated in the IR by borrowing intensity from the OH stretch fundamentals.

6.
J Phys Chem A ; 124(50): 10393-10406, 2020 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-33270448

RESUMO

Decoding the structural information contained in the interfacial vibrational spectrum of water requires understanding how the spectral signatures of individual water molecules respond to their local hydrogen bonding environments. In this study, we isolated the contributions for the five classes of sites that differ according to the number of donor (D) and acceptor (A) hydrogen bonds that characterize each site. These patterns were measured by exploiting the unique properties of the water cluster cage structures formed in the gas phase upon hydration of a series of cations M+·(H2O)n (M = Li, Na, Cs, NH4, CH3NH3, H3O, and n = 5, 20-22). This selection of ions was chosen to systematically express the A, AD, AAD, ADD, and AADD hydrogen bonding motifs. The spectral signatures of each site were measured using two-color, IR-IR isotopomer-selective photofragmentation vibrational spectroscopy of the cryogenically cooled, mass selected cluster ions in which a single intact H2O is introduced without isotopic scrambling, an important advantage afforded by the cluster regime. The resulting patterns provide an unprecedented picture of the intrinsic line shapes and spectral complexities associated with excitation of the individual OH groups, as well as the correlation between the frequencies of the two OH groups on the same water molecule, as a function of network site. The properties of the surrounding water network that govern this frequency map are evaluated by dissecting electronic structure calculations that explore how changes in the nearby network structures, both within and beyond the first hydration shell, affect the local frequency of an OH oscillator. The qualitative trends are recovered with a simple model that correlates the OH frequency with the network-modulated local electron density in the center of the OH bond.

7.
Proc Natl Acad Sci U S A ; 114(24): E4706-E4713, 2017 06 13.
Artigo em Inglês | MEDLINE | ID: mdl-28566495

RESUMO

We report the vibrational spectra of the hydronium and methyl-ammonium ions captured in the C3v binding pocket of the 18-crown-6 ether ionophore. Although the NH stretching bands of the CH3NH3+ ion are consistent with harmonic expectations, the OH stretching bands of H3O+ are surprisingly broad, appearing as a diffuse background absorption with little intensity modulation over 800 cm-1 with an onset ∼400 cm-1 below the harmonic prediction. This structure persists even when only a single OH group is present in the HD2O+ isotopologue, while the OD stretching region displays a regular progression involving a soft mode at about 85 cm-1 These results are rationalized in a vibrationally adiabatic (VA) model in which the motion of the H3O+ ion in the crown pocket is strongly coupled with its OH stretches. In this picture, H3O+ resides in the center of the crown in the vibrational zero-point level, while the minima in the VA potentials associated with the excited OH vibrational states are shifted away from the symmetrical configuration displayed by the ground state. Infrared excitation between these strongly H/D isotope-dependent VA potentials then accounts for most of the broadening in the OH stretching manifold. Specifically, low-frequency motions involving concerted motions of the crown scaffold and the H3O+ ion are driven by a Franck-Condon-like mechanism. In essence, vibrational spectroscopy of these systems can be viewed from the perspective of photochemical interconversion between transient, isomeric forms of the complexes corresponding to the initial stage of intermolecular proton transfer.

8.
J Phys Chem A ; 123(37): 7965-7972, 2019 Sep 19.
Artigo em Inglês | MEDLINE | ID: mdl-31430153

RESUMO

The vibrational spectrum of the protonated water trimer, H+(H2O)3, is surprisingly complex, with many strong features in the expected region of the fundamentals associated with two H-bonded OH groups on the H3O+ core ion. Here we follow how the bands in this region of the spectrum evolve when the energies of the fundamentals in the H-bonded OH stretches are systematically increased by the attachment of increasingly strongly bound "tag" molecules (He, Ar, D2, N2, CO, and H2O) to the free OH position on the hydronium core ion of H+(H2O)3, as well as by replacement of the hydrogen atom in the nonbonded OH group on hydronium with methyl and ethyl groups. This allows for the incremental transformation of the complex band pattern observed in H+(H2O)3 into that of the "Eigen" structure of the protonated water tetramer. Differences among the trajectories of the various bands provide an empirical way to disentangle features primarily due to the displacements of the OH stretches bound to the hydronium core from those arising from anharmonic coupling to states involving one or more quanta in lower frequency modes. The latter are found to be dramatically enhanced when the nominal frequencies of the intermolecular OH stretching modes approach those of the intramolecular bends of the H3O+ and H2O constituents in both H and D isotopologues.

9.
Molecules ; 24(12)2019 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-31242707

RESUMO

For the first time, a nanosilver-coated hollow fiber microfiltration (MF) was fabricated by a simple chemical reduction method, then tested for membrane biofouling mitigation study under extreme high mixed liquor suspended solid (MLSS) concentration for long term. This study presents a simple and novel technique to modify a commercially available MF membrane using silver nanoparticles (AgNPs) followed by an investigation of mitigating membrane biofouling potentials using this modified membrane to compare with an unmodified membrane for 60-day operation period. The modified membranes showed that AgNPs was attached to the MF-membrane successfully with a high density of 119.85 ± 5.42 mg/m2. After long-term testing of 60 days in membrane bioreactor with a MLSS concentration of 11,000 mg/L, specific flux of the AgNPs coated MF (AgNPs-MF) decreased 59.7%, while the specific flux of the unmodified membrane dropped 81.8%, resulted from the increase of transmembrane vacuum pressure for the AgNPs-MF was lower than that of the unmodified one. The resistance-in-series model was used to calculate the resistance coefficients of membrane modules, and the result showed that the cake layer resistance coefficient of the unmodified membrane was 2.7 times higher than that of the AgNPs-MF after the 60-day operation, confirming that AgNPs displayed great antimicrobial properties to mitigate membrane biofouling under such high MLSS.


Assuntos
Incrustação Biológica , Reatores Biológicos , Membranas Artificiais , Nanopartículas Metálicas , Prata , Ultrafiltração , Nanopartículas Metálicas/química , Nanopartículas Metálicas/ultraestrutura , Prata/química , Análise Espectral
10.
J Phys Chem A ; 122(40): 8037-8046, 2018 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-30208709

RESUMO

Vibrational spectra of protonated tryptophan were recorded by predissociation of H2 messenger tags using cryogenic ion traps. We explore the issue of messenger induced spectral changes by solvating TrpH+(H2) n with n = 1-5 to obtain single photon vibrational spectra of TrpH+ and of its partly deuterated isotopomer in the spectral region of 800-4400 cm-1. Depending on the number of messenger molecules, the spectra of several conformational isomers associated with multiple H2 binding locations along with two natural conformations of TrpH+ were found using the two photon MS3IR2 conformational hole burning method. Most probable messenger positions were established by comparison with predictions from DFT calculations on various candidate structures. Mechanical anharmonicity effects associated with the charged amino group were modeled by Born-Oppenheimer ab initio molecular dynamics. The spectra of TrpH+(H2O) m=1,2, recorded by infrared multiphoton dissociation (IRMPD), reveal broad features in the NH stretching region of the NH3+ group, indicating strong hydrogen bonding in acceptor-donor configuration with the benzene ring for the first water molecule, while the second water appears to attach to a less strongly perturbing site, yielding unique transitions associated with the free OH stretching fundamentals. We discuss the structural deformations induced by the water molecules and compare our results to recent experiments on similar hydrated cationic systems.

11.
J Phys Chem A ; 122(48): 9275-9284, 2018 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-30351101

RESUMO

We report vibrational spectra of the cryogenically cooled H9O4+ cation along with those of the D2 tagged HD8O4+ isotopomers using two variations on a two-color, IR-IR double-resonance photoexcitation scheme. The spectrum of the isolated H9O4+ ion consists of two sharp features in the OH stretching region that indicate exclusive formation of the "Eigen" cation, the H3O+·(H2O)3 isomer that corresponds to the filled hydration shell around the hydronium ion. Consistent with this structural assignment, the spectrum of the HD8O4+ isotopologue is resolved into contributions from two isotopomers: one with the single OH group on one of the three solvent water molecules and another in which it resides on the hydronium core ion. The latter spectrum is dominated by a broad feature assigned to the isolated hydronium OH stretching fundamental with an envelope that is similar to that displayed by the H3O+·(H2O)3 isotopologue. The feature appears with a diffuse band ∼380 cm-1 above it, which is assigned to a combination band involving the hydronium OH stretching vibration and the frustrated translation mode of the HD2O+ core and one of the solvating water molecules. These trends are analyzed with anharmonic calculations involving four-mode coupling on a realistic potential surface and interpreted in the context of vibrationally adiabatic potentials based on insights acquired from analysis of the ground state probability amplitudes obtained from diffusion Monte Carlo calculations.

12.
Chemosphere ; 362: 142743, 2024 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-38950740

RESUMO

For the first time, a hyper-thermophilic aerobic (>60 °C) bioreactor has been integrated with direct submerged membrane distillation (MD), highlighting its potential as an advanced wastewater treatment solution. The hyper-thermophilic aerobic bioreactor, operating up to 65 °C, is tailored for high organic removal, while MD efficiently produces clean water. Throughout the study, high removal rates of 99.5% for organic matter, 96.4% for ammonia, and 100% for phosphorus underscored the impressive adaptability of microorganisms to challenging hyper-thermophilic conditions and a successful combination with the MD process. Despite the extreme temperatures and substantial salinity accumulation reaching up to 12,532 µS/cm, the biomass of microorganisms increased by 1.6 times over a 92-day period, representing their remarkable resilience. The distillation flux ranged from 6.15 LMH to 8.25 LMH, benefiting from the temperature gradient in the hyper-thermophilic setting and the design of the tubular submerged MD membrane module. The system also excels in pH control, utilizing fewer alkali and nutritional resources than conventional systems. Meiothermus, Firmicutes, and Bacteroidetes, the three dominant species, played a crucial role, showcasing their significance in adapting to high salinity and decomposing organic matter.

13.
J Hazard Mater ; 427: 128200, 2022 04 05.
Artigo em Inglês | MEDLINE | ID: mdl-34999397

RESUMO

Tetramethylammonium hydroxide (TMAH) is a toxic photoresist developer used in the photolithography process in thin-film transistor liquid crystal display (TFT-LCD) production, and it can be removed through anaerobic treatment. TMAH cannot be released into the environment because of its higher toxicity. A tight membrane, such as a forward osmosis (FO) membrane, together with an anaerobic biological process can ensure that no TMAH is released into the environment. Thus, for the first time, an anaerobic osmotic membrane bioreactor (AnOMBR) hybrid system was developed in this study to treat a low-strength TMAH wastewater and to simultaneously investigate its microbial community. Microfiltration extraction was used to mitigate the salinity accumulation, and a periodically physical water cleaning was utilized to mitigate the FO membrane fouling. The diluted draw solute (MgSO4) was reconcentrated and reused by a membrane distillation (MD) process in the AnOMBR to achieve 99.99% TMAH removal in this AnOMBR-MD hybrid system, thereby ensuring that no TMAH is released into the natural environment. Moreover, the membrane fouling in the feed and draw sides were analyzed through the fluorescence excitation-emission matrix (FEEM) spectrophotometry to confirm that the humic acid-like materials were the primary membrane fouling components in this AnOMBR. Additionally, 16S rRNA metagenomics analysis indicated that Methanosaeta was the predominant contributor to methanogenesis and proliferated during the long-term operation. The methane yield was increased from 0.2 to 0.26 L CH4/g COD when the methanogen species acclimatized to the saline system.


Assuntos
Microbiota , Purificação da Água , Anaerobiose , Reatores Biológicos , Membranas Artificiais , Osmose , Compostos de Amônio Quaternário , RNA Ribossômico 16S/genética , Águas Residuárias , Água
14.
CNS Neurol Disord Drug Targets ; 21(7): 621-630, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-34414874

RESUMO

AIMS: To investigate the efficacy and safety of Cerebrolysin and Cerebrolysin plus nootropics in the routine treatment of patients with acute ischemic stroke (AIS). BACKGROUND: Acute ischemic stroke (AIS) is a leading cause of disability with unmet treatment needs lacking effective drug therapy. Multimodal drugs modulating stroke pathophysiology as Cerebrolysin constitute a good therapeutic option. OBJECTIVE: In this study, we assessed the effects of Cerebrolysin and Cerebrolysin plus nootropics, in comparison with other nootropic drugs alone, on functional, neurological and cognitive recovery of patients with AIS in Vietnam. METHODS: This non-interventional, controlled, open-label, prospective and multicenter study included 398 AIS patients (234 males) treated with Cerebrolysin (n=190; 20 i.v. infusions of 10 ml), other nootropics (comparator group; n=86), or a combination of both (n=122). The study primary endpoint was the modified Ranking Scale (mRS) score on day 90. Secondary endpoints included study-period change in NIHSS score; percentage of well-recovered (mRS 0-2) patients, the proportion of good NIHSS response (≥6 points) cases, and MoCA scores at day 90; and safety indicators. RESULTS: Compared with other nootropics, both Cerebrolysin and combined therapy induced significant improvements (p<0.001) in: Functional recovery (mRS scores); percentage of well-recovered patients (Cerebrolysin: 81.6%; combination: 93.4%; comparator: 43.0%); neurological recovery (study- period NIHSS change); proportion of good NIHSS responders (Cerebrolysin: 77.5%; combination: 92.5%; comparator: 47.6%); and MoCA scores (Cerebrolysin: 23.3±4.8; combination: 23.7±4.1; comparator: 15.9±7.7). Compared to Cerebrolysin, combined therapy improved (p<0.01) mRS outcomes and NIHSS change, but not MoCA scores, in moderate-severe stroke (NIHSS>11) cases only. No drug-related adverse events were reported. CONCLUSION: Cerebrolysin alone or combined with other nootropics was effective and safe in routine AIS treatment, during both acute and recovery phases, which supports its use in daily clinical practice. Others: According to the results of this multicenter study, the importance of reducing differences in the treatment regimens of AIS in Vietnam should be further emphasized.


Assuntos
Isquemia Encefálica , AVC Isquêmico , Fármacos Neuroprotetores , Nootrópicos , Acidente Vascular Cerebral , Aminoácidos , Isquemia Encefálica/complicações , Isquemia Encefálica/tratamento farmacológico , Feminino , Humanos , Masculino , Fármacos Neuroprotetores/uso terapêutico , Nootrópicos/uso terapêutico , Gravidez , Estudos Prospectivos , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/tratamento farmacológico , Resultado do Tratamento , Vietnã
15.
Bioresour Technol ; 342: 125930, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34547711

RESUMO

This study designed a Dynamic-Osmotic membrane bioreactor/nanofiltration (OsMBR/NF) system for municipal wastewater treatment and reuse. Results indicated that a continuously rotating FO module with 60 RPM in Dynamic-OsMBR system could enhance shear stress and reduce cake layer of foulants, leading to higher flux (50%) compared to Traditional-OsMBR during a 40-operation day. A negligible specific reverse salt flux (0.059 G/L) and a water flux of 2.86 LMH were recorded when a mixture of 0.1 M EDTA-2Na/0.1 M Na2CO3/0.9 mM Triton114 functioned as draw solution (DS). It was found that the Dynamic-OsMBR/NF hybrid system could effectively remove pollutants (∼98% COD, ∼99% PO43-P, ∼93% NH4+-N, > 99% suspended solids) from wastewater. In short, this developed system can be considered a breakthrough technology as it successfully minimizes membrane fouling by shear force, and achieves high water quality for reuse by two membrane- barriers.


Assuntos
Membranas Artificiais , Purificação da Água , Reatores Biológicos , Osmose , Águas Residuárias
16.
Nat Chem ; 12(2): 159-164, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31767995

RESUMO

The extremely broad infrared spectrum of water in the OH stretching region is a manifestation of how profoundly a water molecule is distorted when embedded in its extended hydrogen-bonding network. Many effects contribute to this breadth in solution at room temperature, which raises the question as to what the spectrum of a single OH oscillator would be in the absence of thermal fluctuations and coupling to nearby OH groups. We report the intrinsic spectral responses of isolated OH oscillators embedded in two cold (~20 K), hydrogen-bonded water cages adopted by the Cs+·(HDO)(D2O)19 and D3O+·(HDO)(D2O)19 clusters. Most OH oscillators yield single, isolated features that occur with linewidths that increase approximately linearly with their redshifts. Oscillators near 3,400 cm-1, however, occur with a second feature, which indicates that OH stretch excitation of these molecules drives low-frequency, phonon-type motions of the cage. The excited state lifetimes inferred from the broadening are considered in the context of fluctuations in the local electric fields that are available even at low temperature.

17.
Environ Sci Pollut Res Int ; 27(33): 41751-41763, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32700271

RESUMO

Membrane distillation (MD) has a high heat requirement. Integrating MD with thermophilic bioreactors could remedy this problem. A laboratory-scale thermophilic anaerobic granular sludge membrane distillation bioreactor (ThAGS-MDBR) was used to treat wastewater with a high organic loading rate (OLR). Waste heat from ThAGS was used directly for the MD process to reduce energy consumption. The result demonstrated that the ThAGS-MDBR system achieved a high-efficiency removal of chemical oxygen demand (more 99.5%) and NH4+-N (96.4%). Furthermore, the highest methane production from the proposed system was 332 mL/g CODremoved at OLR of 16 kg COD/m3/day. Specifically, an aggregate of densely packed diverse microbial communities in anaerobic granular sludge was the main mechanism for the enhancement of bioreactor tolerance with environmental changes. High-quality distillate water from ThAGS-MDBR was reclaimed in one step with total organic carbon less than 1.7 mg/L and electrical conductivity less than 120 µS/cm. Furthermore, the result of the DNA extraction kit recorded that Methanosaeta thermophila was a critical archaea for high COD removal and bioreactor stability.


Assuntos
Esgotos , Águas Residuárias , Anaerobiose , Reatores Biológicos , Destilação , Metano , Eliminação de Resíduos Líquidos
18.
Environ Sci Pollut Res Int ; 27(28): 34664-34674, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31401797

RESUMO

Progressive freezing is a solvent purification technology with low energy requirements and high concentration efficiency. Although these advantages make it a promising technology, the technique has never been explored for draw solution recovery for forward osmosis (FO). Hence, in this study, the progressive freezing process was used to concentrate three common diluted draw solutions: NaCl, MgCl2, and EDTA-2Na with different ice front speeds, stirring rates, and initial draw solution concentrations. Effective partition and intrinsic partition constants were also evaluated. The results reveal that the freezing process can achieve a draw solution recovery rate of 99.73%, 99.06%, and 98.65% with NaCl, MgCl2, and EDTA-2Na, respectively, using an ice front speed of 0.5 cm/h, a stirring rate of 2.62 m/s, and 30% of percentage of ice phase. Higher concentration efficiency for NaCl and MgCl2 was achieved due to the high solubility of NaCl and MgCl2 increased solute diffusion into the liquid phase solutions. The concentration factors for all three draw solutions exceeded 1.9, indicating that the draw solutes could be reused for the FO process. In addition, the two mass transfer coefficients depended on the ice front speed and the stirring rates were also obtained for scaling up the experiment in the future.


Assuntos
Membranas Artificiais , Purificação da Água , Congelamento , Osmose , Soluções
19.
Bioresour Technol ; 312: 123573, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32470825

RESUMO

For the first time, a novel sponge-based moving bed-anaerobic osmosis membrane bioreactor/membrane distillation (AnOMBR/MD) system using mixed Na3PO4/EDTA-2Na as the draw solution was employed to treat wastewater for enhanced water flux and reduced membrane fouling. Results indicated that the moving sponge-AnOMBR/MD system obtained a stable water flux of 4.01 L/m2 h and less membrane fouling for a period lasting 45 days. Continuous moving sponge around the FO module is the main mechanism for minimizing membrane fouling during the 45-day AnOMBR operation. The proposed system's nutrient removal was almost 100%, thus showing the superiority of simultaneous FO and MD membranes. Nutrient recovery from the MF permeate was best when solution pH was controlled to 9.5, whereby 17.4% (wt/wt) of phosphorus was contained in precipitated components. Moreover, diluted draw solute following AnOMBR was effectively regenerated using the MD process with water flux above 2.48 L/m2 h and salt rejection > 99.99%.


Assuntos
Destilação , Purificação da Água , Anaerobiose , Reatores Biológicos , Membranas Artificiais , Nutrientes , Osmose , Águas Residuárias , Água
20.
Science ; 364(6437): 275-278, 2019 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-31000660

RESUMO

The diffuse vibrational envelope displayed by water precludes direct observation of how different hydrogen-bond topologies dictate the spectral response of individual hydroxy group (OH) oscillators. Using cold, isotopically labeled cluster ions, we report the spectral signatures of a single, intact water (H2O) molecule embedded at various sites in the clathrate-like cage structure adopted by the Cs+·(D2O)20 ion. These patterns reveal the site-dependent correlation between the frequencies of the two OH groups on the same water molecule and establish that the bound OH companion of the free OH group exclusively accounts for bands in the lower-energy region of the spectrum. The observed multiplet structures reveal the homogeneous linewidths of the fundamentals and quantify the anharmonic contributions arising from coupling to both the intramolecular bending and intermolecular soft modes.

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