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1.
Bratisl Lek Listy ; 122(1): 54-64, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33393322

RESUMO

The effect of poly(lactic­co­glycolic acid) (PLGA) on structure, degradation, drug release and mechanical properties of fibrin/pomegranate(F/POM)-based drug­eluting scaffolds have been studied comprehensively. METHODS AND MATERIAL: Nanoparticle-fibrin is prepared from thrombin and fibrinogen dissolved in NaOH and HCl. Then pomegranate powder is added to it. Nanoparticles/pom are provided by freeze drying and freeze milling. The 3-D scaffold of poly(lactide-co­glycolic acid) (PLGA) was prepared via salt­leaching solvent/casting leaching method and impregnated with nanofibrin-pom. Structural and chemical component of the scaffolds were evaluated by transmission and scanning electron microscopy and furrier transmission infrared spectroscopy, respectively. Moreover, the scaffolds were characterized from the degradation rate and drug releasing rate points of view of human Adipose Derive Stem Cells (hADSCs). Cytotoxicity effects of the scaffold were evaluated on hADSCs via MTT assay. RESULTS: The results showed that the size of nanoparticles was about 100 nm. The scaffold had a slow degradation rate and it caused a sustained release pattern of pom. MTT assay indicated that nanoparticles had no cytotoxicity and fibrin-pom nanoparticles increased compressive strength of PLGA/scaffolds dramatically and also caused a proper compressive modulus. CONCLUSIONS: By adding F/POM nanoparticle to PLGA and fabricating a three­dimensional nanocomposite scaffold (PLGA/F/POM nanoparticle), special physical and mechanical properties also suitable for drug release and cell behavior were achieved, which makes it suitable for cartilage tissue engineering applications (Tab. 1, Fig. 7, Ref. 53) Keywords: hybrid composites, drug delivery, carrier, nanoparticles, scaffold.


Assuntos
Nanocompostos , Fibrina , Glicóis , Humanos , Copolímero de Ácido Poliláctico e Ácido Poliglicólico , Romã (Fruta) , Engenharia Tecidual , Tecidos Suporte
2.
Chemosphere ; 265: 129089, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33261841

RESUMO

Herein, degradation of ofloxacin (OFX) by pulsed discharge plasma (PDP) coupled with multi-catalysis using graphene-Fe3O4 nanocomposites was inspected. The graphene-Fe3O4 nanocomposites were prepared by hydrothermal synthesis, and their morphology, specific surface area, chemical bond structure and magnetic property were characterized systematically. Compared with sole Fe3O4, the specific surface area of graphene-Fe3O4 nanocomposites increased from 26.34 m2/g to 125.04 m2/g. The prepared graphene-Fe3O4 nanocomposites had higher paramagnetism and the magnetic strength reached 66.05 emu/g, which was prone to separate from solution. Graphene-Fe3O4 nanocomposites could further accelerate OFX degradation compared to sole Fe3O4. When graphene content was 18 wt%, graphene-Fe3O4 nanocomposites exhibited the highest catalytic activity, and the removal efficiency of OFX enhanced from 65.0% (PDP alone) to 99.9%. 0.23 g/L dosage and acid solution were beneficial for OFX degradation. Higher stability of graphene-Fe3O4 nanocomposites could be maintained although four times use. Graphene-Fe3O4 nanocomposites could catalyze H2O2 and O3 to produce more ·OH. The degradation products of OFX were identified by liquid chromatography mass spectrometry (LC-MS) and ion chromatography (IC). According to the identified products and discrete Fourier transform (DFT), the degradation pathway was inferred. Further toxicity assessment of products manifested that the toxicity of oral rat 50% lethal dose (LD50) and the developmental toxicity of OFX were reduced.


Assuntos
Grafite , Nanocompostos , Poluentes Químicos da Água , Animais , Catálise , Grafite/toxicidade , Peróxido de Hidrogênio , Nanocompostos/toxicidade , Ofloxacino , Plasma , Ratos , Água , Poluentes Químicos da Água/toxicidade
3.
Chemosphere ; 265: 128999, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33302199

RESUMO

A new approach of highly fluxes thin film nanocomposite (TFN) nanofiltration (NF) membranes is reported. The fabricated module was made by incorporation of commercial-Al2O3 (CO.TFN) and camphor-Al2O3NPs (CA.TFN) into polyamide layers throughout the interfacial polymerization method. A simple biological reduction technique was adopted in preparation of camphor-Al2O3 NPs by using CinnamomumCamphora (CC) leaf extract. The crystallography of the commercial and camphor-Al2O3 NPs was examined by XRD and FTIR analyses. The CO.TFN and CA.TFN membranes were characterized by determining their surface roughness, pore size, porosity, zeta potential and contact angle parameters. The morphology and the cross-sectional of the NF membranes were studied by atomic force microscope (AFM) and scanning electron microscope (SEM). NF performance was investigated at various Al2O3 NPs loads, applied pressure, and time. The results, of the membranes fabricated at low cost, showed the high permeable flux and elimination of multivalent cations (Mg2+, Ca2+, and water softening). Incorporating 0.98 mM of camphor-Al2O3 NPs into the TFC membrane increased the water flux up to 4 times compared to only 1.5 times for commercial-Al2O3 NPs. Moreover, the salt rejection of CO.TFN and CA.TFN NF membranes increased to 95.1% and 96.5%, respectively for the feed solution (2 g/L Na2SO4 at 25 °C). The optimized NF membrane module of 0.98 mM camphor-Al2O3-NPs (CA.TFN) shows the maximum water flux 69.0,62.2, 60.5 and 55.4 L/m2.h for the feed solutions of following salts NaCl, Na2SO4, MgCl2 and MgSO4 with high salt rejections 92.4%, 96.5%, 91.7% and 95.3%, respectively. This proves that camphor-Al2O3 NPs have a significant role in increasing the membrane hydrophilicity. Hence, the CA.TFN membrane module proved to be a promising candidate for the real brackish water desalination as that collected from Marsa Alam, Egypt.


Assuntos
Nanocompostos , Nanopartículas , Cânfora , Estudos Transversais , Egito , Águas Salinas
4.
Chemosphere ; 265: 129013, 2021 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-33310314

RESUMO

A photocatalyst based on the integration of reduced graphene oxide (rGO) with Bi4O5Br2 nanosheets was facilely prepared and was confirmed by transmission electron microscope, scanning electron microscope, X-ray diffraction and Raman spectroscopy. The integration of rGO can effectively improve the adsorption and the photocatalytic properties of Bi4O5Br2 nanosheets towards the target antibiotics under visible light irradiation. rGO/Bi4O5Br2 nanocomposite containing 1.0 wt% of rGO exhibits the optimal adsorption and photocatalytic activity towards ciprofloxacin (CIP), norfloxacin (NOR) and tetracycline (TC). The removal efficiencies of CIP, NOR and TC are 97.6%, 80.7% and 98.7%, which are higher than that obtained with Bi4O5Br2 nanosheets. The capture experiments and ESR data show that ·O2-, OH· and h+ are the main active species that participated in the photodegradation system. This work provides a simple strategy to integrate rGO with BixOyXz (X = Cl, Br, I) nanosheets to construct effective photocatalysts for the degradation of antibiotics.


Assuntos
Antibacterianos , Nanocompostos , Adsorção , Catálise , Grafite , Óxidos
5.
J Chromatogr A ; 1635: 461712, 2021 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-33229010

RESUMO

A simple and practical magnetic solid-phase extraction high-performance liquid chromatography-inductively coupled plasma mass spectrometry (MSPE-HPLC-ICP-MS) method for extraction and determination of trace mercury species, including inorganic mercury (IHg), monomethylmercury (MeHg) and ethylmercury (EtHg), was developed. The MSPE adsorbent, urchin-like thiol and thioether-functionalized magnetic covalent organic frameworks (Fe3O4@COF-S-SH), was synthesized by coating covalent organic frameworks (COFs) on the surface of Fe3O4 nanoparticles at room temperature and then easily grafting 1,2-Ethanedithiol on the COFs. The as-prepared Fe3O4@COF-S-SH has strong adsorption capacity for IHg, MeHg and EtHg, with excellent static adsorption capacity: 571, 559 and 564 mg g-1, respectively. The parameters influencing the extraction and enrichment had been optimized, including pH, adsorption and desorption time, composition and amount of the eluent, co-existing ions and dissolved organic materials etc. Under the optimized condition, the limit of detection (3δ) of the proposed method were 0.96, 0.17 and 0.47 ng L-1 for IHg, MeHg and EtHg, and the developed method has high actual enrichment factors of 370, 395, 365-fold for IHg, MeHg and EtHg based on 200 mL samples, respectively. The high accuracy and reproducibility has been proved by the spiked recoveries (96.0‒108 %) in real water samples and determination of the certified reference material. Both the adsorption and desorption process can be completed within 5 min. The proposed method with simple operation, short pre-concentration time and high sensitivity has been successfully applied to mercury speciation at trace levels in the samples with complicated matrices, including underground water, surface water, sea water and fish samples.


Assuntos
Técnicas de Química Analítica/métodos , Magnetismo , Mercúrio/isolamento & purificação , Estruturas Metalorgânicas/química , Nanocompostos/química , Compostos de Sulfidrila/química , Sulfetos/química , Adsorção , Animais , Cromatografia Líquida de Alta Pressão , Peixes , Concentração de Íons de Hidrogênio , Espectrometria de Massas , Mercúrio/química , Reprodutibilidade dos Testes , Extração em Fase Sólida , Temperatura , Água/química
6.
Environ Pollut ; 269: 116173, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33302086

RESUMO

In the current research work, a novel eco-friendly Fe3O4@SiO2 nanocomposite immobilized with Pseudomonas fluorescens biomass in calcium alginate beads (MSAB) was used as biosorbent for the elimination of hazardous Rhodamine B dye from aqueous system. The FTIR, XRD and SEM results showed that the MSAB possessed excellent surface properties for the effective sequestration of Rhodamine B. The batch adsorption results concluded that the adsorption of Rhodamine B using MSAB is highly influenced by the parameters such as pH, adsorbent dosage, initial dye concentration and contact time. The equilibrium and kinetics data get best fitted in the Freundlich isotherm and Pseudo first order kinetics for the studied adsorption system. The Langmuir monolayer adsorption capacity was found to be 229.6 mg/g. The thermodynamic studies showed that the adsorption was spontaneous, feasible and exothermic in nature. The adsorption mechanisms are understood using the Intraparticle diffusion and Boyd model. Thus, this Magnetic silica alginate beads (MSAB) containing dead biomass of Pseudomonas fluorescens is considered to be an ideal biosorbent which can be used as an effective tool in treating the industrial dye wastewater treatment.


Assuntos
Nanocompostos , Pseudomonas fluorescens , Poluentes Químicos da Água , Adsorção , Concentração de Íons de Hidrogênio , Cinética , Fenômenos Magnéticos , Rodaminas , Dióxido de Silício , Termodinâmica
7.
Environ Pollut ; 269: 116067, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33316499

RESUMO

Herein, an efficient visible-light-driven BiFeO3/AgVO3 nanocomposite was effectively fabricated via a facile co-precipitation procedure. The physicochemical properties of BiFeO3/AgVO3 nanocomposites were investigated via Fourier transform-infrared (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), photoluminescence (PL), UV visible diffuse reflectance spectroscopy (DRS) and photoelectrochemical studies (PEC). The photocatalytic activity (PCA) of BiFeO3/AgVO3 nanocomposites was assessed with regard to the photocatalytic degradation of Rhodamine-B (RhB) when subjected to visible light irradiation (VLI). Upon 90 min of illumination, the optimal 3%-BiFeO3/AgVO3 nanocomposite showed a greater photocatalytic degradation, which was ∼3 times higher than the bare AgVO3. The lower PL intensity of 3%-BiFeO3/AgVO3 nanocomposite exposed the low recombination rate, which improved the photo-excited charge carriers separation efficiency. The experimental outcomes showed that the BiFeO3/AgVO3 nanocomposite might be an encouraging material for treatment of industrial and metropolitan wastewater. Moreover, a plausible RhB degradation mechanism was proposed proving the participation of the generated OH and O2- radicals in the degradation over BiFeO3/AgVO3 nanocomposite.


Assuntos
Nanocompostos , Catálise , Luz , Águas Residuárias , Difração de Raios X
8.
Chemosphere ; 263: 128043, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297058

RESUMO

The presence of pharmaceutical micropollutants in water and wastewater is considered a serious environmental issue. To eliminate these pollutants, biodegradation of pharmaceuticals using enzymes such as laccase, is proposed as a green method. In this study, immobilized laccase was used for the removal of two model pharmaceutical compounds, carbamazepine and diclofenac. Polyvinylidene fluoride (PVDF) membrane modified with multi-walled carbon nanotubes (MWCNTs) were synthesized as a tailor-made support for enzyme immobilization. Covalently immobilized laccase from Trametes hirsuta exhibited remarkable activity and activity recovery of 4.47 U/cm2 and 38.31%, respectively. The results also indicated improvement in the operational and thermal stability of the immobilized laccase compared to free laccase. Finally, by using immobilized laccase in a mini-membrane reactor, removal efficiencies of 27% in 48 h and 95% in 4 h were obtained for carbamazepine and diclofenac, respectively. The findings suggest that immobilized laccase on PVDF/MWCNT membranes is a promising catalyst for large-scale water and wastewater treatment which is also compatible with existing treatment facilities.


Assuntos
Nanocompostos , Nanotubos de Carbono , Preparações Farmacêuticas , Enzimas Imobilizadas , Concentração de Íons de Hidrogênio , Lacase , Polyporaceae , Polivinil , Trametes
9.
Chemosphere ; 263: 128104, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297099

RESUMO

Two-dimensional graphene and its hybrid derivatives combined with liquid crystals, polymers, and nanomaterials enable the formation of hybrid nanocomposites possessing extraordinary and unique properties. Among others, these assemblies could exhibit stimulus-induced optical and electrical changes, which are essential for many new switchable device technologies. The current review deals straight forward and versatile techniques of the fabrication of exclusive graphene self-assembly of liquid crystalline polymer nanocomposite which exhibiting novel emerging equities as well as unique functionalities. Unique design makes hybrid composite matrix multidomain structures serve as both alignment and conductive layers, thus sustaining novel switchable device fabrication mechanism. Exhibited ultra thin-film nanocomposite based smart switchable devices are promising candidates for diverse applications in the field of stretchable electronics, energy storage, photodetectors, high contrast displays, and optoelectronics. Furthermore, the brand new device implementation through novel materials have the potentials of cost-effective production, large-area compatibility and scalability, and seamless heterogeneous integration.


Assuntos
Grafite , Cristais Líquidos , Nanocompostos , Condutividade Elétrica , Eletrônica
10.
Chemosphere ; 263: 128250, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297195

RESUMO

Copper(II) phthalocyanine (CuPc) and non-peripheral octamethyl-substituted copper(II) phthalocyanine (N-CuMe2Pc) were combined with reduced graphene oxide (rGO) via a precipitation method to form CuPc/rGO and N-CuMe2Pc/rGO nanocomposites, respectively. CuPc nanorods are distributed on rGO, and N-CuMe2Pc exists as nanorods and nanoparticles on rGO. The Cr(VI) removal ratio of N-CuMe2Pc/rGO exposed in simulated sunlight is 99.0% with a fast photocatalytic reaction rate of 0.0320 min-1, which is approximately 1.5 times faster than that of CuPc/rGO (0.0215 min-1) and far surpasses that of pristine phthalocyanine and rGO. As an electron acceptor, rGO can suppress the recombination of photo-induced electron-hole pairs and also can provide a large surface area for Cr(VI) removal, both of which are beneficial to the reducing capacity of the nanocomposites. The higher removal efficiency of N-CuMe2Pc/rGO compared with that of CuPc/rGO is attributed to the higher specific surface area, higher light harvesting, higher conductivity and more negative lowest unoccupied molecular orbital level of N-CuMe2Pc/rGO. The N-CuMe2Pc/rGO nanocomposite shows excellent photochemical recyclability which is essential for application in wastewater treatment.


Assuntos
Grafite , Nanocompostos , Poluentes Químicos da Água , Catálise , Cromo , Indóis , Compostos Organometálicos
11.
Chemosphere ; 263: 128262, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-33297206

RESUMO

In the present study, novel ZnO/Au/graphitic carbon nitride (g-C3N4) nanocomposites were fabricated via a facile and eco-friendly liquid phase pulsed laser process followed by calcination. Notably, the approach did not necessitate the use of any capping agents or surfactants. The as-prepared photocatalysts were evaluated by various electron microscopy and spectroscopy techniques. The obtained results confirmed good dispersion of the Au nanoparticles (NPs) on the surface of spherical ZnO particles deposited on the g-C3N4 nanosheets. The ZnO/Au/g-C3N4 nanocomposite exhibited substantially enhanced catalytic activity toward the degradation of methylene blue (MB) under simulated solar light irradiation. In particular, the ZnO/Au15/g-C3N4 composite containing 15 wt% Au displayed a rate constant, which was approximately 3 and 5 times greater than those of pristine g-C3N4 and ZnO, respectively. This improved photocatalytic activity of ZnO/Au15/g-C3N4 was attributed to the surface plasmon resonance of Au NPs and the synergistic effects between ZnO and g-C3N4. The boundary between ZnO/Au and g-C3N4 enabled direct migration of the photogenerated electrons from g-C3N4 to ZnO/Au, which hindered the recombination of electron-hole pairs and enhanced the carrier separation efficiency. Additionally, a plausible MB degradation mechanism over the ZnO/Au/g-C3N4 photocatalyst is proposed based on the results of the conducted scavenger study.


Assuntos
Nanopartículas Metálicas , Nanocompostos , Óxido de Zinco , Catálise , Ouro , Águas Residuárias
12.
J Environ Sci (China) ; 101: 123-134, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33334508

RESUMO

Homogeneous and vertically aligned silicon nanowires (SiNWs) were successfully fabricated using silver assisted chemical etching technique. The prepared samples were characterized using scanning electron microscopy, transmission electron microscopy and atomic force microscopy. Photocatalytic degradation properties of graphene oxide (GO) modified SiNWs have been investigated. We found that the SiNWs morphology depends on etching time and etchant composition. The SiNWs length could be tuned from 1 to 42 µm, respectively when varying the etching time from 5 to 30 min. The etchant concentration was found to accelerate the etching process; doubling the concentrations increases the length of the SiNWs by a factor of two for fixed etching time. Changes in bundle morphology were also studied as function of etching parameters. The SiNWs diameter was found to be independent of etching time or etchant composition while the size of the SiNWs bundle increases with increasing etching time and etchant concentration. The addition of GO was found to improve significantly the photocatalytic activity of SiNWs. A strong correlation between etching parameters and photocatalysis efficiency has been observed, mainly for SiNWs prepared at optimum etching time and etchant concentrations of 10 min and 4:1:8. A degradation of 92% was obtained which further improved to 96% by addition of hydrogen peroxide. Only degradation efficiency of 16% and 31% has been observed for bare Si and GO/bare Si samples respectively. The obtained results demonstrate that the developed SiNWs/GO composite exhibits excellent photocatalytic performance and could be used as potential platform for the degradation of organic pollutants.


Assuntos
Grafite , Nanocompostos , Nanofios , Silício
13.
Environ Sci Pollut Res Int ; 28(3): 3386-3405, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32918265

RESUMO

The presence of dyes in wastewater streams poses a great challenge for sustainability and brings the need to develop technologies to treat effluent streams. Here, we propose a mixture of high superficial area carbon-based nanomaterial strategy to improve the removal of basic blue 26 (BB26) by blending porous carbon nitride (CN) and graphene oxide (GO). We prepared CN and GO pristine materials, as well the nanocomposites with mass/ratio 30/70, 50/50, and 70/30, and applied them into BB26 uptake. Nanocomposite 50/50 CN/GO was found to be the better adsorbent, and the optimization of the adsorption revealed a fast equilibrium time of 30 min, after sonication for 2 min, nanocomposite 50/50, and BB26 dye loading of 0.1 g/L and 100 mg/L, respectively. The pH variation had great influence on BB26 uptake, and at ultrapure water pH, the dye removal capacity by the composite reached 917.78 mg/g. At pH 2, a remarkable removal efficiency of 3510.10 mg/g was obtained, probably due to electrostatic interactions among protonated amine groups of the dye and negatively charged CN/GO nanocomposite. The results obtained were best fitted to the pseudo-second-order kinetic model and the Dubinin-Radushkevich isotherm. The adsorption process was thermodynamically spontaneous, and physisorption was the main mechanism, which is based on weak electrostatic and π-π interactions. The dye attached to the CN/GO nanocomposite could be removed by washing with ethyl alcohol, and the adsorbent was reused for five consecutive cycles with high BB26 uptake efficiency. The CN/GO nanocomposite ability to remove the BB26 dye was 21 times higher than those reported in the literature, indicating CN/GO composites as potential filtering materials to basic dyes.


Assuntos
Grafite , Nanocompostos , Poluentes Químicos da Água , Adsorção , Corantes , Cinética , Nitrilos , Poluentes Químicos da Água/análise
14.
Environ Sci Pollut Res Int ; 28(2): 1919-1932, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32862342

RESUMO

Removing Co(II) from wastewater is urgent due to the threat to the environment and human health. In the work, the nanocomposite of graphene oxide-modified palygorskite (mPal-GO) is synthesized by cross-linking one-dimensional palygorskite (Pal) with two-dimensional material graphene oxide (GO), and used to remove Co(II) from wastewater. Its structure is characterized by Fourier transformed infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and Brunauer-Emmett-Teller (BET) surface area measurement. The parameters, such as mass ratio (GO:mPal), temperature, pH, and contact time, are carefully investigated. The results indicate that pseudo-second-order equation and Langmuir isotherm model are the best fitting one in the adsorption process of Co(II) onto mPal-GO. The maximum adsorption capacity achieves 16.9 mg/g at pH = 6.0 and T = 298 K according to the Langmuir model analysis. Furthermore, mPal-GO can be reused more than 5 times with a slight decrease according to the adsorption-desorption cycle experiments. Finally, mPal-GO with the low-cost and easy separation is a promising candidate for removing of Co(II) from wastewater.


Assuntos
Grafite , Nanocompostos , Poluentes Químicos da Água , Adsorção , Humanos , Cinética , Compostos de Magnésio , Compostos de Silício , Espectroscopia de Infravermelho com Transformada de Fourier , Águas Residuárias , Poluentes Químicos da Água/análise
15.
Food Chem ; 340: 128128, 2021 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-33010646

RESUMO

In this research, a novel signal-on aptasensor for highly sensitive detection of zearalenone (ZEN) was reported based on target-induced amplification strategy. Specifically, chitosan functionalized acetylene black and multi-walled carbon nanotubes (CS@AB-MWCNTs) nanocomposite with large specific surface area and excellent conductivity was synthesized and served as the sensing platform. In addition, carboxylated graphene oxide-labeled ZEN binding aptamer (CGO-ZBA) would specifically recognized with ZEN to detach from the electrode, allowing the electrochemical signal of [Fe(CN)6]3-/4- increased more obviously. Under the optimal conditions, the proposed aptasensor exhibited exceptional detection performances for ZEN with a linear range from 10 fg mL-1 to 1 ng mL-1 and a low limit of detection of 3.64 fg mL-1. Given its great sensitivity, excellent selectivity, satisfactory stability and reproducibility, this method would provide a promising application for ZEN and other biomolecules by replacing the corresponding nucleicacidsequences.


Assuntos
Aptâmeros de Nucleotídeos/química , Técnicas Eletroquímicas/métodos , Nanocompostos/química , Zearalenona/análise , Acetileno/química , Quitosana/química , Eletrodos , Grafite/química , Limite de Detecção , Nanotubos de Carbono/química , Reprodutibilidade dos Testes , Zearalenona/química
16.
Water Res ; 189: 116673, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33276212

RESUMO

The efficient removal of arsenite [As(III)] from groundwater remains a great challenge. Nanoscale oxides of Fe(III), Zr(IV), and Al(III) can selectively remove arsenic from groundwater through inner-sphere complexation. However, owing to polysilicate coatings formation on nanoparticles surface, the ubiquitous silicate exerts remarkably adverse effects on As(III) removal. Herein, we propose a new strategy to enhance silicate resistance of nanoscale oxides by embedding them inside the redox polymer host. As a proof-of-concept, the nanocomposite HFO@PS-Cl was employed to remove As(III) from silicate-containing water. The polymer host (PS-Cl) contains active chlorine to oxidize As(III) into arsenate [As(V)], and the embedded Fe(III) oxides enabling specific adsorption toward arsenic. Silicate exerts negligible effects on As(III) removal by HFO@PS-Cl in pH 3-7, but increasing the residual arsenic concentration from 49 µg/L to 166 µg/L for the solutions treated by HFO@PS-N, i.e., the nanoscale Fe(III) oxides embedded inside the polymer host without active chlorine. During the six cyclic decontamination-regeneration assays, HFO@PS-Cl steadily reduces As(III) below 10 µg/L. As for HFO@PS-N, however, the residual arsenic increases to ~57 µg/L in the sixth run. In column mode, HFO@PS-Cl column generates >3200-bed volume (BV) clean water ([As]<10 µg/L) from the simulated As(III)-contaminated groundwater. In contrast, the values for As(V)-contaminated water and HFO@PS-N column are only ~650 BV and ~608 BV, respectively. The stoichiometric assays, XPS, and in-situ ATR-FTIR analysis demonstrate that silicate polymerization is intensively suppressed by the protons produced during As(III) oxidation, thus rendering HFO@PS-Cl with excellent silicate resistant properties.


Assuntos
Arsênico , Arsenitos , Nanocompostos , Poluentes Químicos da Água , Purificação da Água , Adsorção , Compostos Férricos , Oxirredução , Óxidos , Polímeros , Silicatos , Água
17.
J Environ Manage ; 278(Pt 1): 111519, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-33113395

RESUMO

With the increase of industrialization, there is an urgent need for developing technologies to detect and remove toxic pollutants from water bodies. The pollutants are often released to the environment due to the consumption of raw materials that are necessary for the production of technological goods (such as chemical and pharmaceutical compounds, metals, and alloys or foods). Amongst all the remediation techniques, adsorption is considered as one of the preferred techniques, due to its fast and efficient removal of contaminants. Novel materials, which are engineered for selective and responsive water remediation, have also recently revealed a strong potential in the detection of pollutants. Here, current trends of silica-graphene (SG) porous composites for the removal of oils, organic solvents, heavy metals, and dyes are reviewed in detail. Insights on the modifications of composites to enhance their sorption performance have been highlighted. In addition, the detection of pollutants using porous SG nanocomposites is also critically reviewed. Overall, SG composites reveal a strong potential as nanostructure materials with improved efficiency for environmental-based applications.


Assuntos
Recuperação e Remediação Ambiental , Grafite , Metais Pesados , Nanocompostos , Poluentes Químicos da Água , Purificação da Água , Adsorção , Porosidade , Dióxido de Silício
18.
Ecotoxicol Environ Saf ; 207: 111276, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32931965

RESUMO

Aquatic contamination from the accumulation of pharmaceuticals has induced severe toxicological impact to the ecological environment, especially from non-steroidal anti-inflammatory drugs (NSAIDs). Real-time monitoring of flutamide, which is a class of NSAIDs, is very significant in environmental protection. In this work, we have synthesized the hexagonal-h boron nitride decorated on bismuth oxide (Bi2O3/h-BN) based nanocomposite for the effective electrochemical detection of flutamide (FTM). The structural and morphological information of the heterostructured Bi2O3/h-BN nanocomposite was analyzed by using a sequence of characterization methods. Voltammetric techniques were used to evaluate the analytical performance of the Bi2O3/h-BN modified screen-printed carbon electrode (SPCE) for the FTM detection. The Bi2O3/h-BN modified SPCE displays a synergetic catalytic effect for the reduction of FTM due to large surface area, numerous active sites, fast charge transfer and abundant defects. The proposed electrochemical sensing platform demonstrates high selectivity, low detection limit (9.0 nM), good linear ranges (0.04-87 µM) and short response time for the detection of FTM. The feasibility of the electrochemical sensor has been proved by the successful application to determine FTM in environmental samples.


Assuntos
Bismuto/química , Compostos de Boro/química , Flutamida/química , Nanocompostos/química , Carbono/química , Catálise , Técnicas Eletroquímicas/métodos , Eletrodos
19.
Water Res ; 188: 116571, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-33137528

RESUMO

Clay-polymer nanocomposites (CPNs) have been studied for two decades as sorbents for water pollutants, but their applicability remains limited. Our aim in this review is to present the latest progress in CPN research using a meta-analysis approach and identify key steps necessary to bridge the gap between basic research and CPN application. Based on results extracted from 99 research articles on CPNs and 8 review articles on other widely studies sorbents, CPNs had higher adsorption capacities for several inorganic and organic pollutant classes (including heavy metals, oxyanions, and dyes, n = 308 observations). We applied principal component analysis, analysis of variance, and multiple linear regressions to test how CPN and pollutant properties correlated with Langmuir adsorption model coefficients. While adsorption was, surprisingly, not influenced by mineral properties, it was influenced by CPN fabrication method, polymer functional groups, and pollutant properties. For example, among the pollutant classes, heavy metals had the highest adsorption capacity but the lowest adsorption affinity. On the other hand, dyes had high adsorption affinities, as reflected by the linear correlation between adsorption affinity and pollutant molecular weight. Scaling from 'basic research' to 'technological application' requires testing CPN performance in real water, application in columns, comparison to commercial sorbents, regeneration, and cost evaluation. However, our survey indicates that of the 158 observations, only 20 compared the CPN's performance to that of a commercial sorbent. We anticipate that this review will promote the design of smart and functional CPNs, which can then evolve into an effective water treatment technology.


Assuntos
Nanocompostos , Poluentes Químicos da Água , Purificação da Água , Adsorção , Argila , Polímeros , Água , Poluentes Químicos da Água/análise
20.
Chemosphere ; 263: 127892, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32822943

RESUMO

Nitrogen-doped porous graphene oxide (N-PGO) was synthesized, characterized, and applied as a hydrophilic nanomaterial in fabrication of polyethersulfone (PES) membrane for Reactive Red 195 dye and bovine serum albumin (BSA) protein separation. The N-PGO nanosheets not merely showed a good adhesion towards polymers, but simultaneously promoted hydrogen bonding action. Therefore, high-efficiency permeation passageway in the separation layer of membranes was attained. X-ray photoelectron spectroscopy (XPS), energy dispersive spectroscopy (EDX) and Fourier transform infra-red spectroscopy (FTIR) analyses approved nitrogen doping, which increased hydrophilicity and hydrogen bonding ability of PGO in water filtration. The pure water permeation of nanocomposite membranes could reach as high as 190 L m-2 h-1 at 3 bar. A dye rejection efficiency higher than 92% and BSA rejection higher than 95% were accordingly obtained. Atomic force microscopy (AFM) images approved formation of a rough surface that was decreased by addition of low amounts of the PGO. SEM images provided from the surface also confirmed enlarged pore size and increased porosity. Antifouling properties were investigated by BSA filtration, and results showed that the flux recovery ratio of the N-PGO membrane was improved. Overall, the N-PGO hybrid membranes exhibited potential for application in separation of typical proteins and dyes with good antifouling properties.


Assuntos
Corantes/química , Nanocompostos/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Animais , Bovinos , Corantes/análise , Filtração , Grafite/química , Ligação de Hidrogênio , Interações Hidrofóbicas e Hidrofílicas , Membranas Artificiais , Nitrogênio , Polímeros/química , Porosidade , Soroalbumina Bovina/química , Sulfonas , Água/química , Poluentes Químicos da Água/análise
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