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1.
Electrophoresis ; 2024 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-39329504

RESUMO

A method was developed for studying mass transfer kinetics at lipid bilayers of liposomes. Elution peaks of coumarin were measured by liposome electrokinetic chromatography (LEKC). Four types of phospholipids having different alkyl chains were used for preparing liposomes, which were used as pseudo-stationary phases in LEKC systems. Rate constants of permeation across lipid bilayers of liposomes or of adsorption at lipid membranes were determined by analyzing the first absolute and second central moments of the elution peaks measured by LEKC. The rate constants of permeation or adsorption tend to decrease with an increase in the carbon number of the alkyl chains of phospholipids. It was demonstrated that the moment analysis of elution peak profiles measured by LEKC is effective for determining lipid membrane permeability or adsorption kinetics. Compared with other conventional techniques, the method has some advantages for studying mass transfer kinetics at lipid bilayers. Solute permeation across or solute adsorption at real lipid bilayers of liposomes is analyzed. The principle of the method is the analysis of separation behavior in LEKC, which is different from that of the other ones. It is expected that the method contributes to the kinetic study of mass transfer at lipid bilayers from various perspectives.

2.
Small ; : e2401214, 2024 Jun 17.
Artigo em Inglês | MEDLINE | ID: mdl-38884200

RESUMO

Nowadays, capacitive deionization (CDI) has emerged as a prominent technology in the desalination field, typically utilizing porous carbons as electrodes. However, the precise significance of electrode properties and operational conditions in shaping desalination performance remains blurry, necessitating numerous time-consuming and resource-intensive CDI experiments. Machine learning (ML) presents an emerging solution, offering the prospect of predicting CDI performance with minimal investment in electrode material synthesis and testing. Herein, four ML models are used for predicting the CDI performance of porous carbons. Among them, the gradient boosting model delivers the best performance on test set with low root mean square error values of 2.13 mg g-1 and 0.073 mg g-1 min-1 for predicting desalination capacity and rate, respectively. Furthermore, SHapley Additive exPlanations is introduced to analyze the significance of electrode properties and operational conditions. It highlights that electrolyte concentration and specific surface area exert a substantially more influential role in determining desalination performance compared to other features. Ultimately, experimental validation employing metal-organic frameworks-derived porous carbons and biomass-derived porous carbons as CDI electrodes is conducted to affirm the prediction accuracy of ML models. This study pioneers ML techniques for predicting CDI performance, offering a compelling strategy for advancing CDI technology.

3.
Sci Total Environ ; 937: 173534, 2024 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-38802020

RESUMO

Granite, as the natural barrier for the disposal of high-level radioactive waste, plays an important role in ensuring environmental and public safety. The safety assessment of the repository depends on the reliable migration parameters of radionuclides in granite. In this study, we developed a kinetic adsorption-advection-dispersion model based on first-order adsorption kinetics. It introduces a first-order adsorption rate coefficient to describe the kinetics of adsorption process and accounts for other crucial mechanisms affecting the migration of radionuclide ions, namely, the electromigration, electroosmosis, and dispersion. This model is then applied to interpret the experimental results of electromigration of tracer ions in intact granite. The results show that for the weakly adsorbed radionuclides studied, iodide and selenite, the effective diffusion coefficients and formation factors calculated by this model are in constant with those derived from the classical advection-dispersion model based on linear adsorption equilibrium. By contrast, for the moderately or strongly adsorbed tracer ions studied, including cobalt, cesium, and strontium, the migration parameters calculated by this model exhibit significantly less uncertainty than those obtained from the advection-dispersion model simulations. The advection-dispersion model based on the first order adsorption kinetics introduces the first order adsorption rate coefficient, and considers the influence of electromigration, electroosmosis and dispersion mechanism, which helps to explain the migration mechanism of nuclide ions in intact granite more accurately.

4.
NMR Biomed ; 36(12): e5023, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-37620002

RESUMO

A complementary safety assessment of the specific absorption rate (SAR) of the electromagnetic energy was performed in a prototype 8Tx/16Rx RF array for cardiac magnetic resonance imaging (MRI) at 7 T. The study aimed to address two critical aspects of 7-T SAR safety not always explicitly examined by coil vendors: (i) the influence of an RF-array position on a peak SAR value, and (ii) the risk of exceeding the permitted maximal SAR in the tissue surrounding conductive passive implants. The full-wave 3D electromagnetic simulations for the thorax with shifted array position and the whole-body volume in the presence of a dental retainer, an intrauterine contraceptive device (IUD), and a hip joint implant, were performed for two human voxel models. The effect of the array displacement on the SAR was simulated for seven array locations on the thorax shifted from the central position in different directions on 50 mm. The peak SAR values for both models were analyzed for the three phase-only transmit vectors optimized for B1 + homogeneity and transmit efficiency. Peak SAR values due to the shifts of the array position increase up to ≈50%. The worst-case peak SAR value for a dental retainer was found to be in the range of 10% of the maximal SAR in the tissue within the array's borders. For the IUD and artificial hip joint implants the effect was found to be negligible (peak SAR < 1% of the SAR within array borders). In addition to simulations for cardiac MRI, we performed a preliminary B1 + shimming and SAR-safety analysis for the same RF-array at various positions lower on the body trunk to assess a potential application in imaging abdominopelvic organs (prostate, kidney, and liver). The most promising target for an ad hoc alternative application of the array was found to be the prostate.


Assuntos
Imageamento por Ressonância Magnética , Tórax , Masculino , Humanos , Imagens de Fantasmas , Imageamento por Ressonância Magnética/métodos , Coração/diagnóstico por imagem , Próstata
5.
Antibiotics (Basel) ; 12(4)2023 Apr 07.
Artigo em Inglês | MEDLINE | ID: mdl-37107086

RESUMO

For ideal gasses, the likelihood of collision of two molecules is a function of concentrations as well as environmental factors such as temperature. This too is the case for particles diffusing within liquids. Two such particles are bacteria and their viruses, the latter called bacteriophages or phages. Here, I review the basic process of predicting the likelihoods of phage collision with bacteria. This is a key step governing rates of phage-virion adsorption to their bacterial hosts, thereby underlying a large fraction of the potential for a given phage concentration to affect a susceptible bacterial population. Understanding what can influence those rates is very relevant to appreciating both phage ecology and the phage therapy of bacterial infections, i.e., where phages are used to augment or replace antibiotics; so too adsorption rates are highly important for predicting the potential for phage-mediated biological control of environmental bacteria. Particularly emphasized here, however, are numerous complications on phage adsorption rates beyond as dictated by the ideals of standard adsorption theory. These include movements other than due to diffusion, various hindrances to diffusive movement, and the influence of assorted heterogeneities. Considered chiefly are the biological consequences of these various phenomena rather than their mathematical underpinnings.

6.
Nanomaterials (Basel) ; 13(7)2023 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-37049241

RESUMO

Metal-organic frameworks (MOFs) are one of the most promising adsorbents in the adsorption cooling system (ACS) for their outstanding water adsorption performance. Notwithstanding that fact, numerous reports pay more attention to the ACS performance improvement through enhancing equilibrium water uptake of MOFs. However, adsorption cooling performance, including specific cooling power (SCP) and coefficient of performance for cooling (COPC) of MOF/water working pairs, always depends on the water adsorption kinetics of MOFs in ACS. In this work, to increase the water adsorption rate, the preparation of MOP/MIL-101(Cr) was achieved by encapsulating hydrophilic metal-organic polyhedral (MOP) into MIL-101(Cr). It was found that the hydrophilicity of MOP/MIL-101(Cr) was enhanced upon hydrophilic MOP3 encapsulation, resulting in a remarkable improvement in water adsorption rates. Furthermore, both SCP and COPC for MOP/MIL-101(Cr)-water working pairs were also improved because of the fast water adsorption of MOP/MIL-101(Cr). In brief, an effective approach to enhance the water adsorption rate and cooling performance of MOF-water working pairs through enhancing the hydrophilicity of MOFs by encapsulating MOP into MOFs was reported in this work, which provides a new strategy for broadening the application of MOF composites in ACS.

7.
ACS Appl Mater Interfaces ; 15(10): 13589-13599, 2023 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-36864004

RESUMO

The efficient and renewable recovery of cesium and strontium by absorption from a new type of geothermal water liquid mineral resource is highly desirable but still challenging. In this work, a new Zr-doped layered potassium thiostannate adsorbent (KZrTS) was first synthesized and used for Cs+ and Sr2+ green and efficient adsorption. It was found that KZrTS had very fast adsorption kinetics toward both Cs+ and Sr2+ with an equilibrium reached within 1 min, and the theoretical maximum adsorption capacities for Cs+ and Sr2+ were 402.84 and 84.88 mg/g, respectively. Moreover, to solve the loss problem of the engineering application of the powdered adsorbent KZrTS, KZrTS was uniformly coated with polysulfone by wet spinning technology to form micrometer-level filament-like absorbents (Fiber-KZrTS), whose adsorption equilibrium rates and capacities toward Cs+ and Sr2+ are almost the same as that of powder. Furthermore, Fiber-KZrTS showed excellent reusability, and the adsorption performance remained virtually unchanged after 20 cycles. Therefore, Fiber-KZrTS has potential application for green and efficient cesium and strontium recovery from geothermal water.

8.
Environ Pollut ; 319: 121019, 2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36621712

RESUMO

Arsenate reducing bacteria (AsRB) enhance arsenic (As) release via reducing As(V) to As(III), and As mobility is usually controlled by As(III) re-uptake on in-situ formed secondary iron minerals. The re-uptake of As(III) under groundwater flow conditions significantly impacts the fate and transport of As. Herein, a novel As(V)-reducing bacterium Alkaliphilus IMB was isolated in an As-contaminated soil. Scanning transmission X-ray microscopy showed that dissolved As(V) was mainly bound to the cell walls whereas dissolved As(III) was homogeneously distributed around IMB, indicating that As(V) reduction occurs outside the cell membrane. To explore the effect of IMB on As mobility, IMB was incubated with As-loaded nanoscale zero-valent iron (nZVI) residues under static and flowing conditions. IMB reduced 100% dissolved As(V) to As(III) even in a short contact time (∼1 h) during flowing incubation. The formation of As(III) did not influence As mobility under static condition as evidenced by the comparable concentrations of released As in the presence of IMB (8.5% to total As) and the abiotic control (10% to total As). Biogenic As(III) was re-adsorbed on the solids as shown by the higher ratio of solid-bound As(III) to total As in the presence of IMB (54%) than that in the abiotic control (12%). By contrast, the degree of As(III) re-adsorption was inhibited in the flowing environment, as suggested by the lower As(III) ratio in the solid (31%). This inhibition can be ascribed to the relatively slow adsorption of As(III) compared with the quick reduction of As(V) (∼1 h). Thus, IMB significantly enhanced As release during flowing incubation as shown that 9.8% As was released in the presence of IMB while 2.1% As in the abiotic control. This study found the contrary effect of AsRB on As mobility in static and flowing environments, highlighting the importance of re-adsorption rate of As(III).


Assuntos
Arsênio , Ferro , Ferro/química , Arsênio/metabolismo , Oxirredução , Arseniatos/metabolismo , Adsorção
9.
Environ Sci Pollut Res Int ; 30(11): 28975-28989, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36402883

RESUMO

Recently, there has been a clear understanding of the mechanism and influencing factors of ferrihydrite (Fh) phase transformation catalyzed by Fe(II); however, these factors mainly belong to environmental conditions and exogenous substances. And there is a lack of research on the effect of soil composition and structure on the phase transformation of Fh. Therefore, this study investigated the effects of montmorillonite (Mt) on the adsorption of Fe(II) and phase transformation of Fh under near-neutral pH. The initial rates ([Formula: see text]) of Elovich equation demonstrated the addition of Mt inhibited the adsorption of Fh but simultaneously accelerated the initial adsorption, thus increasing the adsorption of the system (e.g., 22.09-25.03 mg/g as increased Mt under pH 6.5) due to its high surface charge density. Increased pH enhances the surface charge density by promoting the deprotonation of the surface group (Fe-OH, Al-OH, and Si-OH) and consequently increases adsorption of Fe(II) (e.g., 17.97-22.09 mg/g as increased pH of pure Fh). Based on the previous method of extracting labile Fe(III), we found that pH promotes the initial formation of labile Fe(III) by increasing electron transfer and promoting recrystallization caused by bridging condensation, via increased -OH. Although Mt inhibits the adsorption of Fh, it promotes the formation of labile Fe(III) by increasing the system adsorption and bond with Fh. The results of the analysis of variance showed both pH and solid ratio influence significantly on the maximum adsorption (p = 6.81 × 10-9 and 2.54 × 10-3) and the conversion ratios of labile Fe(III) (p = 3.43 × 10-24 and 9.16 × 10-43).


Assuntos
Bentonita , Compostos Férricos , Compostos Férricos/química , Bentonita/química , Adsorção , Oxirredução , Concentração de Íons de Hidrogênio , Compostos Ferrosos
10.
Environ Sci Pollut Res Int ; 29(22): 33785-33795, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35028831

RESUMO

To know about the reasons leading to variations in dust control efficiency of the surfactant solution spray on coal dust (from the same coal source) with different diameters, the changes of coal dust surface features (specific surface area, pore volume, gas adsorption, and surface potential) with crush degrees and their effects on the wettability were investigated. The experimental results indicated that the surface characteristics of coal dust showed remarkably positive correlations with the crush degree. For example, dust size was reduced from 114.96 to 18.71 µm, the pore volume and gas adsorption of coal dust surface was enhanced by 75%, 104.5%, respectively. It made gas film around dust particles more easily been generated, hindering the contact between dust particles and droplets. The adsorption rate of the surfactant molecules on the coal dust surface was significantly reduced with the dust size decreased, increasing the difficulty of capturing coal dust by surfactant solution. Additionally, based on the linear fitting analysis between surface features and the dust control efficiency, it was indicated that the increased gas adsorption and pore structures on the dust surface was the key factors weakening the dust removal efficiency of the surfactant solution from the perspective of the physical features of coal dust. This study was conducive to optimizing the surfactant-aided dust control technology to better capture coal dust with small size.

11.
J Colloid Interface Sci ; 608(Pt 2): 1457-1462, 2022 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-34749137

RESUMO

HYPOTHESIS: Hydrogen geo-storage is considered as an option for large scale hydrogen storage in a full-scale hydrogen economy. Among different types of subsurface formations, coal seams look to be one of the best suitable options as coal's micro/nano pore structure can adsorb a huge amount of gas (e.g. hydrogen) which can be withdrawn again once needed. However, literature lacks fundamental data regarding H2 diffusion in coal. EXPERIMENTS: In this study, we measured H2 adsorption rate in an Australian anthracite coal sample at isothermal conditions for four different temperatures (20 °C, 30 °C, 45 °C and 60 °C), at equilibrium pressure âˆ¼ 13 bar, and calculated H2 diffusion coefficient ( [Formula: see text] ) at each temperature. CO2 adsorption rates were measured for the same sample at similar temperatures and equilibrium pressure for comparison. FINDINGS: Results show that H2 adsorption rate, and consequently [Formula: see text] , increases by temperature. [Formula: see text] values are one order of magnitude larger than the equivalent [Formula: see text] values for the whole studied temperature range 20-60 °C. [Formula: see text] / [Formula: see text] also shows an increasing trend versus temperature. CO2 adsorption capacity at equilibrium pressure is about 5 times higher than that of H2 in all studied temperatures. Both H2 and CO2 adsorption capacities, at equilibrium pressure, slightly decrease as temperature rises.

12.
Nanotechnology ; 33(10)2021 Dec 16.
Artigo em Inglês | MEDLINE | ID: mdl-34844230

RESUMO

By experimental and density functional theory calculations, the toxic gases (O3and NO2) sensing capability and mechanism of ZnO NRs and Ag/ZnO NRs have been comparatively studied in this work. Ag NPs arrays were employed for the growth of ZnO NRs. The experimental results show that when ZnO NRs are grown on Ag NPs, the response and adsorption rate towards the gases change significantly. The TDOS plot shows that the HOMO-LUMO gap changes after interaction with different oxidizing gases, and the peak intensity also decreases confirming the electron are transferred from ZnO to NO2and O3. The response to gases decreases and the adsorption reaction rate increases in Ag/ZnO NRs, as calculated by the Eyring-Polanyi equation, which is very similar to our experimental data. We also find that the absorption coefficient is different for O3and NO2. Finally, experimental response and theoretical results were compared and found to be in good agreement.

13.
R Soc Open Sci ; 8(6): 201789, 2021 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-34109032

RESUMO

Metal oxide-loaded biochars are a promising material to remove phosphate from polluted water to ultra-low concentrations. To facilitate preparing the metal oxide-loaded biochar with the best phosphate adsorption performance, five biochars loaded with Al, Ca, Fe, La and Mg oxides, respectively (Al-BC, Ca-BC, Fe-BC, La-BC and Mg-BC) were produced using Phragmites australis pretreated with 0.1 mol AlCl3, CaCl2, FeCl3, LaCl3 and MgCl2, respectively, characterized, and phosphate adsorption kinetics and isotherms of the biochars were determined. The maximum phosphate adsorption capacities (Qm ) of the biochars ranked as Al-BC (219.87 mg g-1) > Mg-BC (112.45 mg g-1) > Ca-BC (81.46 mg g-1) > Fe-BC (46.61 mg g-1) > La-BC (38.93 mg g-1). The time to reach the adsorption equilibrium ranked as La-BC (1 h) < Ca-BC (12 h) < Mg-BC (24 h) = Fe-BC (24 h)

14.
J Colloid Interface Sci ; 596: 173-183, 2021 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-33839350

RESUMO

HYPOTHESIS: High hydrostatic pressure treatment causes structural changes in interfacial-active ß-lactoglobulin (ß-lg). We hypothesized that the pressure-induced structural changes affect the intra- and intermolecular interactions which determine the interfacial activity of ß-lg. The conducted experimental and numerical investigations could contribute to the mechanistic understanding of the adsorption behavior of proteins in food-related emulsions. EXPERIMENTS: We treated ß-lg in water at pH 7 with high hydrostatic pressures up to 600 MPa for 10 min at 20 °C. The secondary structure was characterized with Fourier-transform infrared spectroscopy (FTIR) and circular dichroism (CD), the surface hydrophobicity and charge with fluorescence-spectroscopy and ζ-potential, and the quaternary structure with membrane-osmometry, analytical ultracentrifugation (AUC) and mass spectrometry (MS). Experimental analyses were supported through molecular dynamic (MD) simulations. The adsorption behavior was investigated with pendant drop analysis. FINDINGS: MD simulation revealed a pressure-induced molten globule state of ß-lg, confirmed by an unfolding of ß-sheets with FTIR, a stabilization of α-helices with CD and loss in tertiary structure induced by an increase in surface hydrophobicity. Membrane-osmometry, AUC and MS indicated the formation of non-covalently linked dimers that migrated slower through the water phase, adsorbed more quickly due to hydrophobic interactions with the oil, and lowered the interfacial tension more strongly than reference ß-lg.


Assuntos
Lactoglobulinas , Óleos , Adsorção , Emulsões , Pressão Hidrostática
15.
J Sci Food Agric ; 101(10): 4201-4206, 2021 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-33420739

RESUMO

BACKGROUND: The poor palatability, low digestibility, and unpleasant color of parboiled rice (PR) have severely hampered its acceptance by consumers. It is hence necessary and urgent to develop a new method for producing high-quality PR. In the current study, the effect of high hydrostatic pressure (HHP) pre-soaking on the color, textural properties, and the degree of retrogradation of PR was investigated. RESULTS: With HHP from 100 to 500 MPa, the water adsorption rate increased and cooking time decreased. Parboiled rice samples presented higher lightness scores (L) and had lower color intensity (B). Compared with a control group, PR samples treated with high-pressure pre-soaking showed a reduction of hardness values from 0.69% to 32.99%, and gumminess values also decreased from 8.58% to 33.62%. The differential scanning calorimetry (DSC) results indicated that the enthalpy values of PR samples decreased after high pressure pre-soaking. The molecular structure of PR characterized by Fourier transform infrared spectrometry confirmed that HHP pre-soaking could decrease the retrogradation level. CONCLUSION: The findings outlined above suggest that the texture and retrogradation properties of PR were improved after high-pressure pre-soaking. © 2021 Society of Chemical Industry.


Assuntos
Culinária/métodos , Manipulação de Alimentos/métodos , Oryza/química , Varredura Diferencial de Calorimetria , Culinária/instrumentação , Dureza , Temperatura Alta , Pressão Hidrostática , Sementes/química
16.
ACS Appl Mater Interfaces ; 13(2): 2694-2709, 2021 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-33400496

RESUMO

A novel CO2-responsive cotton as an eco-friendly adsorbent derived from poly(4-acryloyloxybenzophenone-co-2-(dimethylamino) ethyl methacrylate) and cotton was fabricated via a facile and fast dip-coating method. As expected, upon CO2 stimulation, the protonated cotton presented CO2-induced "on-off" selective adsorption behaviors toward anionic dyes owing to electrostatic interactions. The adsorption isotherms and kinetics of the CO2-responsive cotton toward anionic dyes obeyed the Langmuir isotherm and pseudo-second-order kinetics models, respectively. It is noteworthy that the CO2-responsive cotton exhibited high adsorption capacity and ultrafast adsorption rate toward anionic dyes with the maximum adsorption capacities of 1785.71 mg g-1 for methyl orange (MO), 1108.65 mg g-1 for methyl blue (MB), and 1315.79 mg g-1 for naphthol green B (NGB), following the adsorption equilibrium times of 5 min for MO, 3 min for MB, and 4 min for NGB. Moreover, the CO2-responsive cotton also exhibited high removal efficiency toward anionic dyes in synthetic dye effluent. Additionally, the CO2-responsive cotton could be facilely regenerated via heat treatment under mild conditions and presented stable adsorption properties even after 15 cycles. Finally, the as-prepared CO2-responsive cotton exhibited outstanding antibacterial activity against E. coli and S. aureus. In summary, this novel CO2-responsive cotton can be viewed as a promising eco-friendly adsorbent material for potential scalable application in dye-contaminated wastewater remediation.

17.
Chemosphere ; 255: 126965, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32417513

RESUMO

Adsorption rate is a critical parameter in the design of effective biosorbent treatment systems for heavy metals removal. Though numerous studies have identified the physico-chemical properties of biosorbents that exert influence on the adsorption rate, such influence has not been mathematically defined, limiting the effective design of adsorption systems. This study quantifies the influence of biosorbent physico-chemical properties including, specific surface area, surface functional groups, pore size, pore volume and zeta potential on the adsorption rate in relation to three divalent metal cations. Mathematical equations were developed to predict the influence of physico-chemical properties on pseudo second order kinetic constant and thereby predict the adsorption rate. Tea factory waste and coconut shell biochar were mixed in different weight percentages to vary the physico-chemical properties under consideration. Four different initial metal ion concentrations were used. Relationship between pseudo second order kinetic constant at each concentration with physico-chemical properties was quantified using regression analysis. The experimental analysis revealed that among the physico-chemical properties, acidic surface functional groups had the most profound influence on sorption mechanisms. Reliability and accuracy of the predictive models were significantly improved when separate models were developed for two ranges of initial metal ion concentrations. The outcomes of this study will contribute to the effective design and optimization of biosorbent mixtures with the capacity to remove Pb2+, Cu2+ and Cd2+ in wastewater.


Assuntos
Metais Pesados/química , Modelos Químicos , Poluentes Químicos da Água/química , Adsorção , Carvão Vegetal , Cocos , Concentração de Íons de Hidrogênio , Cinética , Metais Pesados/análise , Reprodutibilidade dos Testes , Águas Residuárias/química , Poluentes Químicos da Água/análise
18.
ACS Appl Mater Interfaces ; 12(8): 9775-9781, 2020 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-32011857

RESUMO

The extraction of lithium from seawater has attracted much interest as a means to meet increasing demand for lithium with the rapid expansion of the electric vehicle and electronics markets. Herein, a renewable and recyclable hydrogen manganese oxide (HMO)-modified cellulose film was developed and investigated toward the extraction of lithium from lithium-containing aqueous solutions. The porous film was characterized, and its extraction efficacy and selectivity toward lithium from an aqueous solution (ppm level) and seawater (ppb level) were investigated. The HMO/cellulose film exhibited a higher Li+ adsorption capacity (21.6 mg g-1 HMO) than HMO/polymer (e.g., poly(vinyl chloride) or poly(vinylidene fluoride)) films, which have been examined in the literature for lithium extraction, because of its multidimensional porosity and hydrophilicity. The kinetics analysis based on a pseudo-second-order model indicated that the Li+ extraction rate of the HMO/cellulose film was 3 times higher than that achieved by the HMO particle alone (i.e., 0.075; cf. 0.023 g mg-1 h-1). Furthermore, the HMO/cellulose film displayed high selectivity for Li+ when exposed to seawater-the extraction of Li+ reached 99%, whereas that of the other ions present in seawater (i.e., Sr2+, K+, and Ca2+) was <4%. In addition, the adsorption capacity and mechanical strength of the HMO/cellulose film remained stable even after eight adsorption-desorption cycles. The present findings demonstrate the potential of the present HMO/cellulose film for the recovery of Li+ from seawater or wastewater.

19.
Polymers (Basel) ; 11(5)2019 May 20.
Artigo em Inglês | MEDLINE | ID: mdl-31137564

RESUMO

This paper describes a procedure to measure the permeability P, diffusivity D, and rate of adsorption k1, thus determining the solubility S and rate of desorption k2 of He, N2, O2, CH4, and CO2 on a polydimethylsiloxane (PDMS) membrane. The described procedure is able to determine experimentally all the physical quantities that characterize the gas transport process through a thin rubber polymer membrane. The experiments were carried out at room temperature and at a transmembrane pressure of 1 atm. The results are in good agreement with the available data in the literature and offer an evaluation of k1 and k2.

20.
Carbohydr Polym ; 213: 352-360, 2019 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-30879679

RESUMO

Persistent organic pollutants, including plasticizers, pesticides, pharmaceuticals and endocrine disrupters, have posed a serious threat to water safety and human health. Addressing this problem calls out new materials of purifying water with high efficiency. Here, a series of cross-linked ß-cyclodextrin polymers (ß-CDPs) with hierarchically micro-mesoporous structure and high surface area were first synthesized by introducing polymer of intrinsic microporosity (PIM) and used for adsorptive removal of organic micropollutants from water. The chemical compositions and porous structures of the obtained ß-CDPs were characterized in detail. Adsorption data showed that the quasi-second-order adsorption rate constant and maximal adsorption capacity of ß-CDPs towards bisphenol A was up to 3.88 g mg-1 min-1 and 502 mg g-1, almost 2.6 and 5.7 times as large as those of the state-of-the-art porous ß-CD polymer, respectively. Further, hierarchically porous ß-CDPs also demonstrated ultrafast adsorption rates and high adsorption capacities towards various organic pollutants under the synergistic effect of micropores and mesopores. In addition, ß-CDPs were easily regenerated by simple ethanol cleaning and kept high removal ability over 5 cycles. The virtues of extraordinary adsorption ability and convenient regeneration offer ß-CDPs potential applications in water purification.

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