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1.
Ecotoxicol Environ Saf ; 203: 111026, 2020 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-32888594

RESUMO

The detection of phenolic compounds, i.e. resorcinol (RC) catechol (CC) and hydroquinone (HQ) are important due to their extremely hazardous impact and poor environmental degradation. In this work, a novel and sensitive composite of electrochemically reduced graphene oxide-poly(Procion Red MX-5B)/gold nanoparticles modified glassy carbon electrode (GCE/ERGO-poly(PR)/AuNPs) was assembled for voltammetric detection of benzenediol isomers (RC, CC, and HQ). The nanocomposite displayed high peak currents towards the oxidation of RC, HQ, and CC compared to non-modified GCE. The peak-to-peak separations were 0.44 and 0.10 V for RC-CC and CC-HQ, respectively. The limit of detections were 53, 53, and 79 nM for HQ, CC, and RC with sensitivities of 4.61, 4.38, and 0.56 µA/µM (S/N = 3), respectively. The nanocomposite displayed adequate reproducibility, besides good stability and acceptable recoveries for wastewater and cosmetic samples analyses.


Assuntos
Compostos Azo/química , Derivados de Benzeno/análise , Técnicas Eletroquímicas/métodos , Ouro/química , Grafite/química , Nanocompostos/química , Poluentes Químicos da Água/análise , Cosméticos/química , Eletrodos , Nanopartículas Metálicas/química , Oxirredução , Reprodutibilidade dos Testes , Águas Residuárias/química
2.
Nat Commun ; 11(1): 4465, 2020 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-32901012

RESUMO

Titanium implants have been widely used in bone tissue engineering for decades. However, orthopedic implant-associated infections increase the risk of implant failure and even lead to amputation in severe cases. Although TiO2 has photocatalytic activity to produce reactive oxygen species (ROS), the recombination of generated electrons and holes limits its antibacterial ability. Here, we describe a graphdiyne (GDY) composite TiO2 nanofiber that combats implant infections through enhanced photocatalysis and prolonged antibacterial ability. In addition, GDY-modified TiO2 nanofibers exert superior biocompatibility and osteoinductive abilities for cell adhesion and differentiation, thus contributing to the bone tissue regeneration process in drug-resistant bacteria-induced implant infection.


Assuntos
Antibacterianos/química , Grafite , Nanofibras/química , Próteses e Implantes , Infecções Relacionadas à Prótese/prevenção & controle , Titânio , Células 3T3 , Animais , Materiais Biocompatíveis/química , Regeneração Óssea , Sobrevivência Celular , Modelos Animais de Doenças , Feminino , Teste de Materiais , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Camundongos , Nanocompostos/química , Osteogênese , Processos Fotoquímicos , Infecções Estafilocócicas/prevenção & controle
3.
Int J Nanomedicine ; 15: 6421-6432, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32922009

RESUMO

Purpose: Expanded research on the biomedical applications of graphene has shown promising results, although interactions between cells and graphene are still unclear. The current study aims to dissect the cellular and molecular effects of graphene nanocomposite in photothermal therapy against cancer, and to evaluate its efficacy. Methods: In this study, a reduced graphene oxide and iron oxide (rGO-Fe3O4) nanocomposite was obtained by chemical synthesis. The nanocomposite was fully characterized by Raman spectroscopy, TEM, VSM and thermal profiling. Cell-nanocomposite interaction was evaluated by confocal microscopy and viability assays on cancer cell line HeLa. The efficacy of the thermal therapy and changes in gene expression of Bcl-2 and Hsp70 was assessed. Results: The resulting rGO-Fe3O4 nanocomposite exhibited superparamagnetic properties and the capacity to increase the surrounding temperature by 18-20°C with respect to the initial temperature. The studies of cell-nanocomposite interaction showed that rGO-Fe3O4 attaches to cell membrane but there is a range of concentration at which the nanomaterial preserves cell viability. Photothermal therapy reduced cell viability to 32.6% and 23.7% with 50 and 100 µg/mL of nanomaterial, respectively. The effect of treatment on the molecular mechanism of cell death demonstrated an overexpression of anti-apoptotic proteins Hsp70 and Bcl-2 as an initial response to the therapy and depending on the aggressiveness of the treatment. Conclusion: The results of this study contribute to understanding the interactions between cell and graphene and support its application in photothermal therapy against cancer due to its promising results.


Assuntos
Compostos Férricos/química , Grafite/química , Hipertermia Induzida , Nanocompostos/química , Neoplasias/terapia , Fototerapia , Apoptose/genética , Comunicação Celular , Morte Celular/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica , Células HeLa , Humanos , Nanocompostos/ultraestrutura , Neoplasias/genética , Neoplasias/patologia , Oxirredução , Análise Espectral Raman , Temperatura , Resultado do Tratamento
4.
PLoS One ; 15(8): e0237389, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32797116

RESUMO

In the present work, a series of magnetically separable Fe3O4/g-C3N4/MoO3 nanocomposite catalysts were prepared. The as-prepared catalysts were characterized by XRD, EDX, TEM, FT-IR, UV-Vis DRS, TGA, PL, BET and VSM. The photocatalytic activity of photocatalytic materials was evaluated by catalytic degradation of tetracycline solution under visible light irradiation. Furthermore, the influences of weight percent of MoO3 and scavengers of the reactive species on the degradation activity were investigated. The results showed that the Fe3O4/g-C3N4/MoO3 (30%) nanocomposites exhibited highest removal ability for TC, 94% TC was removed during the treatment. Photocatalytic activity of Fe3O4/g-C3N4/MoO3 (30%) was about 6.9, 5, and 19.9-fold higher than those of the MoO3, g-C3N4, and Fe3O4/g-C3N4 samples, respectively. The excellent photocatalytic performance was mainly attributed to the Z-scheme structure formed between MoO3 and g-C3N4, which enhanced the efficient separation of the electron-hole and sufficient utilization charge carriers for generating active radials. The highly improved activity was also partially beneficial from the increase in adsorption of the photocatalysts in visible range due to the combinaion of Fe3O4. Superoxide ions (·O2-) was the primary reactive species for the photocatalytic degradation of TC, as degradation rate were decreased to 6% in solution containing benzoquinone (BQ). Data indicate that the novel Fe3O4/g-C3N4/MoO3 was favorable for the degradation of high concentrations of tetracycline in water.


Assuntos
Óxido Ferroso-Férrico/química , Grafite/química , Molibdênio/química , Nanocompostos/química , Compostos de Nitrogênio/química , Óxidos/química , Processos Fotoquímicos , Tetraciclina/química , Água/química , Catálise , Luz , Imãs/química , Tetraciclina/isolamento & purificação , Poluentes Químicos da Água/química , Poluentes Químicos da Água/isolamento & purificação
5.
J Chromatogr A ; 1627: 461382, 2020 Sep 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823094

RESUMO

A method is described for the functionalization of magnetic carbon nanotubes to recognize aristolochic acid Ⅰ and Ⅱ. 3-Glycidyloxypropyltrimethoxysilane was used as a coupling agent to immobilize adenine on a solid support. The morphology and structure of adenine-coated magnetic carbon nanotubes was investigated using transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD) and a vibrating sample magnetometer (VSM). The adsorption performance of the adenine-coated magnetic carbon nanotubes was evaluated via adsorption isotherms, the kinetics and selectivity tests. The adsorption capacity of the adenine-functionalized sorbent for aristolochic acid Ⅰ was determined to be 24.5 µg mg-1. By combining magnetic solid phase extraction with HPLC detection, a method was developed to enrich and detect aristolochic acids used in traditional Chinese medicine. A satisfactory recovery (92.7 - 97.5% for aristolochic acid Ⅰ and 92.6 - 99.4% for aristolochic acid Ⅱ) and an acceptable relative standard deviation (<4.0%) were obtained.


Assuntos
Adenina/química , Ácidos Aristolóquicos/isolamento & purificação , Fenômenos Magnéticos , Nanotubos de Carbono/química , Adsorção , Medicamentos de Ervas Chinesas/química , Compostos Férricos/síntese química , Compostos Férricos/química , Concentração de Íons de Hidrogênio , Cinética , Nanocompostos/química , Nanotubos de Carbono/ultraestrutura , Concentração Osmolar , Reprodutibilidade dos Testes , Dióxido de Silício/síntese química , Dióxido de Silício/química , Extração em Fase Sólida , Temperatura , Difração de Raios X
6.
Chemosphere ; 255: 127052, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32679636

RESUMO

In this study, polypyrrole/carboxymethyl cellulose nanocomposite particles (PPy/CMC NPs) were synthesized and applied for removal of reactive red 56 (RR56)and reactive blue 160 (RB160) as highly toxic dyes. The amount of CMC was found significantly effective on the surface adsorption efficiency. Different optimization methods including the genetic programming, response surface methodology, and artificial neural network (ANN) were used to optimize the effect of different parameters including pH, adsorption time, initial dye concentration and adsorbent dose. The maximum adsorption of RR56 and RB160 were found under the following optimum conditions: pH of 4 and 5, adsorption time of 55 min and 52 min for RR56 and RB160, respectively, initial dye concentration of 100 mg/L and adsorbent dose of 0.09 g for both dyes. were obtained for RR56 and RB160, respectively. Also, the results indicated that ANN method could predict the experimental adsorption data with higher accuracy than other methods. The analysis of ANN results indicated that the adsorbent dose is the main factor in RR56 removal, followed by time, pH and initial concentration, respectively. However, initial concentration mostly determines the RB160 removal process. The isotherm data for both dyes followed the Langmuir isotherm model with a maximum adsorption capacity of 104.9 mg/g and 120.7 mg/g for RR56 and RB160, respectively. In addition, thermodynamic studies indicated the endothermic adsorption process for both studied dyes. Moreover, DFT calculations were carried out to obtain more insight into the interactions between the dyes and adsorbent. The results showed that the hydrogen bondings and Van der Waals interactions are dominant forces between the two studied dyes and PPy/CMC composite. Furthermore, the interaction energies calculated by DFT confirmed the experimental adsorption data, where PPy/CMC resulted in higher removal of both dyes compared to PPy. The developed nanocomposite showed considerable reusability up to 3 cylces of the batch adsorption process.


Assuntos
Carboximetilcelulose Sódica/química , Corantes/química , Nanocompostos/química , Adsorção , Compostos Azo , Benzenossulfonatos , Teoria da Densidade Funcional , Cinética , Nanopartículas , Polímeros , Pirróis , Termodinâmica , Poluentes Químicos da Água
7.
J Chromatogr A ; 1625: 461307, 2020 Aug 16.
Artigo em Inglês | MEDLINE | ID: mdl-32709350

RESUMO

In this study, the ultrasonic-assisted dispersive solid phase extraction (UA-d-SPE) method coupled to gas chromatography-mass spectrometry (GC-MS) was applied for the analysis of phthalate esters in drinking water and distilled herbal beverages (Rosa, Mentha, Cichorium). A new nanocomposite based on layered double hydroxide supported on graphene oxide was synthesized and modified by sulfonated polyaniline via a simple one-pot in-situ polymerization method. The structure and morphology of the nanocomposite was confirmed by means of complementary techniques: Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and transmission electron microscopy. The effects of key parameters including adsorbent mass, type and amount of back extraction solvent, extraction and desorption time, pH of the solution and ionic strength were optimized and good precision and sensitivity were achieved. Under the optimum conditions, the limits of detection were between 0.06-0.3 ng mL-1 in aqueous solutions. The hybrid nanomaterial exhibited good adsorption ability toward phthalates in drinking water and distilled herbal beverages. The relative standard deviations (RSD%) for beverage samples varied from 0.1% to 9.9% (n = 3). The relative recoveries varied from 54.5% to 112.6%.


Assuntos
Compostos de Anilina/química , Bebidas/análise , Grafite/química , Hidróxidos/química , Ácidos Ftálicos/isolamento & purificação , Extração em Fase Sólida/métodos , Ácidos Sulfônicos/química , Ultrassom/métodos , Adsorção , Ésteres/análise , Cromatografia Gasosa-Espectrometria de Massas , Concentração de Íons de Hidrogênio , Nanocompostos/química , Concentração Osmolar , Ácidos Ftálicos/análise , Preparações de Plantas/química , Reprodutibilidade dos Testes , Solventes/química , Espectroscopia de Infravermelho com Transformada de Fourier , Fatores de Tempo , Difração de Raios X
8.
Chemosphere ; 259: 127421, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32603965

RESUMO

Nanocomposites with ultrahigh adsorption capabilities are highly desired for efficient wastewater remediation. Unfortunately, most of the nanomaterial based adsorbents showing inevitable limitation such as leaching and agglomeration led to the emerging field of carbonaceous hybrid materials with nanocomposites. Herein, we demonstrated a simple and low-temperature hydrothermal assisted preparation of Fe-Al based nanocomposites immobilized using carbon spheres. Towards this, we have approached two different routes one is hybridizing with nanocomposite and another is doping on the surface of the carbon spheres. Iron doping played a dual-faceted role of active site for robust adsorption as well as induce magnetic property to the composites. The micro-cleaners have been extensively characterized for their physicochemical properties and adsorption capacities using FTIR, Raman, XRD, BET isotherms and XPS techniques. Remarkably, microcleaners shows robust adsorption where >99% removal was obtained within 10 min for 50 mg L-1 concentrated Eriochrome Black T (EBT) dye using 0.01 g of materials. Further, adsorption data followed the pseudo second order kinetics while the equilibrium data fitted perfectly into the Langmuir adsorption equation. As synthesized user friendly microcleaner (HTC-2) exhibits maximum adsorption capacity (qmax) of 564.97 mg g-1 for EBT dye at pH 4. Hence, the preliminary results highlight the potential of the composites to be used in pretreatment steps of industry effluents.


Assuntos
Corantes/química , Nanocompostos/química , Poluentes Químicos da Água/química , Adsorção , Ânions , Compostos Azo , Carbono , Concentração de Íons de Hidrogênio , Ferro , Cinética , Águas Residuárias , Poluentes Químicos da Água/análise
9.
Chemosphere ; 260: 127587, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32663673

RESUMO

In this work, a three-dimension grapnene-PbO2 (3DG-PbO2) composite anode was prepared using coelectrodeposition technology for electrocatalytic oxidation of perfluorooctane sulfonate (PFOS). The effect of 3DG on the surface morphology, structure and electrocatalytic activity of PbO2 electrode was investigated. The results indicated that the 3DG-PbO2-0.08 anode (3DG concentration in electrodeposition solution was 0.08 g L-1) possessed the best electrocatalytic activity due to its stronger ·OH radicals generation capacity, more active sites and smaller charge-transfer resistance. The degradation rate constant of PFOS on 3DG-PbO2-0.08 anode was 2.33 times than that of pure PbO2 anode. Additionally, the by-products formed in electrocatalytic degradation of PFOS were identified and a PFOS degradation pathway was proposed accordingly, which was dominated by the dissociation of -CF2- groups via the attack of ·OH radicals. Finally, the toxicity evolution of degradation solution was examined to evaluate the ecological risk of electrocatalytic oxidation of PFOS by acute toxicity assays to zebrafish embryos.


Assuntos
Ácidos Alcanossulfônicos/análise , Técnicas Eletroquímicas/métodos , Fluorcarbonetos/análise , Grafite/química , Chumbo/química , Nanocompostos/química , Óxidos/química , Titânio/química , Poluentes Químicos da Água/análise , Ácidos Alcanossulfônicos/toxicidade , Animais , Eletrodos , Galvanoplastia , Embrião não Mamífero/efeitos dos fármacos , Fluorcarbonetos/toxicidade , Oxirredução , Poluentes Químicos da Água/toxicidade , Peixe-Zebra
10.
Chemosphere ; 260: 127593, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32679377

RESUMO

In this study we demonstrate Sulphonated Polyhedral oligomeric silsesquioxane (S-POSS) incorporated Sulphonated Poly Ether Ether Ketone (SPEEK) as an effective cation exchange membrane (CEM) for improving performance and sustainability in a fabricated tubular Microbial Fuel Cell (MFC). The organic-inorganic caged frame of S-POSS enables several ion conducting channels thereby resulting in better proton conductivity and water uptake in addition to hydroxide ions native in POSS. Among the membranes, SPEEK+ 5 wt% S-POSS exhibits a highest maximum performance of 162 ± 1.4 mW m-2 with the highest IEC of 1.8 ± 0.05 meq g-1. Microbial community analysis reveals the predominance of several bacterial strains contributing to wide range of mechanisms. Three phyla including Betaproteobacteria, Gammaproteobacteria and Firmicutes showed maximum predominance. In addition to a novel nanocomposite membrane, the present research introduces perceptions of two metabolic mechanisms of the microbial community available which opens pathway for future insights on how other miniatures involve in electron transfer mechanisms.


Assuntos
Fontes de Energia Bioelétrica/microbiologia , Cetonas/química , Membranas Artificiais , Nanocompostos/química , Compostos de Organossilício/química , Polietilenoglicóis/química , Ácidos Sulfônicos/química , Condutividade Elétrica
11.
Food Chem ; 333: 127495, 2020 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-32663747

RESUMO

Various pesticides employed in modern agriculture result in large amounts of pesticide residues in agricultural production, greatly threatening human health. Herein, we report a facile approach to fabricate a reduced graphene oxide/cyclodextrin modified glassy carbon electrode (rGO/CD/GCE) for the sensitive electrochemical sensing of imidacloprid (IDP). Three different modified electrodes using CDs (α-, ß-, γ-CD) were fabricated, and their electrochemical performance was further studied. The results demonstrate that α-CD possesses the best signal amplification for IDP. Compared with wet-chemical synthesis of rGO/CDs (W-rGO/CDs), the electrochemical synthesis of rGO/CDs (E-rGO/CDs) produced sensors that showed better performance for IDP sensing. Taking advantage of prepared E-rGO/α-CD nanocomposite, the fabricated sensor offered a low detection limit (0.02 µM) with a wider linear range (0.5-40 µM) and long-term stability. The new sensor was successfully applied for the detection of IDP in brown rice, providing a new technique for efficient and convenient monitoring of pesticide residues in food.


Assuntos
Ciclodextrinas/química , Técnicas Eletroquímicas/métodos , Grafite/química , Inseticidas/análise , Neonicotinoides/análise , Nitrocompostos/análise , Oryza/química , Carbono/química , Técnicas Eletroquímicas/instrumentação , Eletrodos , Contaminação de Alimentos/análise , Nanocompostos/química , Oxirredução , Sementes/química , Sensibilidade e Especificidade
12.
Chemosphere ; 257: 127277, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32702805

RESUMO

This work reports the fabrication of SiO2@TW nanocomposites and their application for Pb2+ and Cd2+ ions sequestration from simulated water. Residual tea waste has also been used for metal ions sequestration to compare the potential of SiO2@TW nanocomposites. The SEM, TEM, BET, FTIR and EDX techniques were employed for the characterization of SiO2@TW nanocomposites and residual tea waste. Particle sizes of SiO2@TW nanocomposites was in the range of 6.8-12 nm. The experiments were carried out in batch mode to explore the effect of various operating parameters on the sequestration of Pb2+ and Cd2+ ions from water. The experimental data was subjected to various thermodynamic, kinetic and isothermic models. According to Langmuir model, the maximum adsorption efficiency of the SiO2@TW nanocomposites was 153 mg/g for Pb2+ and 222 mg/g for Cd2+ but maximum adsorption efficiency of residual tea waste for Pb2+ was 125 mg/g and for Cd2+ was 142.9 mg/g. This study suggested that due to the presence of active sites SiO2@TW nanocomposites has greater potential for metal sequestration than residual tea waste.


Assuntos
Cádmio/análise , Chumbo/análise , Nanocompostos/química , Eliminação de Resíduos Líquidos/métodos , Poluentes Químicos da Água/análise , Adsorção , Íons , Cinética , Dióxido de Silício , Chá , Termodinâmica , Águas Residuárias/química , Purificação da Água/métodos
13.
Int J Nanomedicine ; 15: 4205-4224, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32606673

RESUMO

Cardiovascular diseases are the number one cause of heart failure and death in the world, and the transplantation of the heart is an effective and viable choice for treatment despite presenting many disadvantages (most notably, transplant heart availability). To overcome this problem, cardiac tissue engineering is considered a promising approach by using implantable artificial blood vessels, injectable gels, and cardiac patches (to name a few) made from biodegradable polymers. Biodegradable polymers are classified into two main categories: natural and synthetic polymers. Natural biodegradable polymers have some distinct advantages such as biodegradability, abundant availability, and renewability but have some significant drawbacks such as rapid degradation, insufficient electrical conductivity, immunological reaction, and poor mechanical properties for cardiac tissue engineering. Synthetic biodegradable polymers have some advantages such as strong mechanical properties, controlled structure, great processing flexibility, and usually no immunological concerns; however, they have some drawbacks such as a lack of cell attachment and possible low biocompatibility. Some applications have combined the best of both and exciting new natural/synthetic composites have been utilized. Recently, the use of nanostructured polymers and polymer nanocomposites has revolutionized the field of cardiac tissue engineering due to their enhanced mechanical, electrical, and surface properties promoting tissue growth. In this review, recent research on the use of biodegradable natural/synthetic nanocomposite polymers in cardiac tissue engineering is presented with forward looking thoughts provided for what is needed for the field to mature.


Assuntos
Materiais Biocompatíveis/química , Coração/fisiologia , Nanocompostos/química , Nanomedicina , Polímeros/química , Engenharia Tecidual/métodos , Animais , Humanos , Nanocompostos/ultraestrutura
14.
PLoS One ; 15(6): e0234815, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32584837

RESUMO

Nanocomposites (NCs) of crosslinked polyaniline (CPA)-coated oxidized carbon nanomaterials (OXCNMs) were fabricated as a very sensitive and simple electrochemical sensor to be utilized in 2,4-dichlorophenol (2,4-DCPH) detection. CPA/OXCNMs NCs were prepared by chemical copolymerization of polyaniline with triphenylamine and p-phenylenediamine in the presence of OXCNMs. The CPA/GO-OXSWCNTNCs exhibited a higher affinity for the oxidation of chlorophenols compared to the glassy carbon electrode (GCE), CPA/GCE, and other NCs. Cyclic voltammetry was performed to investigate and assess the electrocatalytic oxidation of 2,4-DCPH on the modified GCE. The compound yielded a well-defined voltammetric response in a Britton-Robinson buffer (pH 5) at 0.54 V (vs. silver chloride electrode). Quantitative determination of 2,4-DCPH was performed by differential pulse voltammetry under optimal conditions in the concentration range of 0.05 to 1.2 nmol L-1, and a linear calibration graph was obtained. The detection limit (S/N = 3) was found to be 4.2 nmol L-1. In addition, the results demonstrated that the CPA/GO-OXSWCNTs/GCE sensor exhibited a strong anti-interference ability, reproducibility, and stability. The prepared CPA/GO-OXSWCNTs/GCE sensor was used to rapidly detect 2,4-DCPH with a high degree of sensitivity in fish farm water with proven levels of satisfactory recoveries.


Assuntos
Compostos de Anilina/química , Carbono/química , Clorofenóis/análise , Eletroquímica/instrumentação , Limite de Detecção , Nanocompostos/química , Clorofenóis/química , Eletrodos , Oxirredução , Fatores de Tempo
15.
Ecotoxicol Environ Saf ; 201: 110862, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32559691

RESUMO

In this study, a novel electrochemical sensor based on self-assembled rod-like lanthanum hydroxide-oxidized multi-walled carbon nanotubes (La(OH)3-OxMWCNTs) nanocomposite was developed for sensitive determination of p-nitrophenol (p-NP). The La(OH)3-OxMWCNTs nanocomposite with an interpenetrating networks structure was characterized by field emission electron microscope (FE-SEM), Fourier transform infrared (FT-IR) spectroscopy, Raman spectra and X-ray photoelectron spectroscopy (XPS). The cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) measurements were performed to study the electrochemical behaviors of La(OH)3-OxMWCNTs modified glassy carbon electrode (La(OH)3-OxMWCNTs/GCE). The La(OH)3-OxMWCNTs/GCE was used for sensitive determination of p-NP by CV and linear sweep voltammetry (LSV). Under the optimum conditions, the peak currents of LSV versus the concentrations of p-NP in the range 1.0-30.0 µmol L-1 showed a good linear relationship (R2=0.9971), and the limit of detection (LOD) was calculated to be 0.27 µmol L-1 (signal-to-noise ratio of 3, S/N=3). The recoveries of p-NP in real samples of industrial wastewater and Xiangjiang water at La(OH)3-OxMWCNTs/GCE were in the range of 95.62-110.75% with relative standard deviation (RSD) in the range of 1.65-3.85%. The intra-day and inter-day precisions were estimated to be less than 2.76% (n= 5), indicating that La(OH)3-OxMWCNTs/GCE possessed highly stability. In addition, La(OH)3-OxMWCNTs/GCE sensor showed good anti-interference ability for determination of p-NP in aqueous mixtures containing high concentrations of inorganic and organic interferents, and a decrease of oxidation peak currents by less than 3.57% relative to the initial levels indicated it possessed excellent selectivity. Therefore, La(OH)3-OxMWCNTs/GCE could be used as a fast, selective and sensitive electrochemical sensor platform for the selective determination and quantification of aqueous p-NP.


Assuntos
Técnicas Eletroquímicas/métodos , Lantânio/química , Nanocompostos/química , Nanotubos de Carbono/química , Nitrofenóis/análise , Eletrodos , Limite de Detecção , Oxirredução
16.
Chemosphere ; 259: 127292, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32593007

RESUMO

A novel pie-like structure of vertically stacked ZnO-nanodisks on Cu-nanoplates interlayer is prepared for the first time by a facile synthesis. The photochemical activity of the as-prepared samples was evaluated by the degradation of Rhodamine B (RhB) under UV-light. Because of the formation of heterojunction and closely-bonded layered structure, the novel nanocomposites can restrain the recombination of charge carriers and have better collection ability of light. The photocatalytic experiments show that the composites are 258% of the catalytic activity of pure ZnO-nanodisks prepared by the same method, and the target pollutant RhB was almost completely degraded (96.5%) within only 10 mins. The novel Cu-nanoplates/ZnO-nanodisks assembled materials with greatly promoted performance are of significant interest for chemical and environmental applications.


Assuntos
Cobre/química , Nanopartículas Metálicas/química , Óxido de Zinco/química , Catálise , Nanocompostos/química , Rodaminas
17.
Chemosphere ; 258: 127324, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32544812

RESUMO

Water is an extremely essential compound for human life and, hence, accessing drinking water is very important all over the world. Nowadays, due to the urbanization and industrialization, several noxious pollutants are discharged into water. Water pollution by various cytotoxic contaminants, e.g. heavy metal ions, drugs, pesticides, dyes, residues a drastic public health issue for human beings; hence, this topic has been receiving much attention for the specific approaches and technologies to remove hazardous contaminants from water and wastewater. In the current review, the cytotoxicity of different sorts of aquatic pollutants for mammalian is presented. In addition, we will overview the recent advances in various nanocomposite-based adsorbents and different approaches of pollutants removal from water/wastewater with several examples to provide a backdrop for future research.


Assuntos
Nanocompostos/química , Poluentes Químicos da Água/química , Purificação da Água/métodos , Adsorção , Poluentes Ambientais , Humanos , Metais Pesados/química , Praguicidas/análise , Águas Residuárias/química , Água
18.
Int J Food Microbiol ; 331: 108763, 2020 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-32574819

RESUMO

Using titanium teraisopropoxide (TTIP) as the hydrolysis material, titanium dioxide (TiO2) (6.3-11.1 nm) nanoparticles were synthesized via the sol-gel method and reinforced into poly lactic acid (PLA)/TiO2 nanocomposite films by casting. The effect of increasing amounts of TiO2 on the structure and properties of PLA/TiO2 nanocomposite films were evaluated. These results indicated that self-aggregation of TiO2 nanoparticles in PLA films could be avoided via sol-gel and casting processes. The presence of TiO2 significantly improved the tensile strength and thermal stability of films. The PLA/TiO2 (0.6 wt%) film exhibited the highest photocatalytic activity efficiency under UV irradiation and displayed high antibacterial activities with optimal inhibition zones of Staphylococcus aureus, followed by Escherichia dispersibility of TiO2 in films were responsible for those improvements. This study suggests that PLA/TiO2 nanocomposite films could be a promising antimicrobial alternative material to conventional plastic packages.


Assuntos
Escherichia coli/efeitos dos fármacos , Microbiologia de Alimentos/métodos , Embalagem de Alimentos , Nanocompostos/química , Poliésteres/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Titânio/farmacologia , Antibacterianos/química , Antibacterianos/farmacologia , Nanocompostos/efeitos da radiação , Nanopartículas/química , Poliésteres/síntese química , Raios Ultravioleta
19.
Artigo em Inglês | MEDLINE | ID: mdl-32532181

RESUMO

Diesel oil spills in marine environments pose a severe threat to both aquatic and terrestrial ecosystems. Photocatalysis is an environment-friendly method for marine oil remediation; however, its practical usage is limited due to several issues. In this study, we demonstrate the enhanced efficacy of doped CuO/ZrO2 photocatalyst at degrading marine diesel in comparison to undoped ZrO2. The photocatalysts were prepared using co-precipitation method, and their physical and chemical properties were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and ultraviolet-visible spectroscopy (UV-Vis). XRD analysis showed that the photocatalytic crystallite size of ZrO2 and CuO/ZrO2 was 28.80 nm and 40.32 nm, respectively. Both catalysts exhibited stable crystalline forms. UV-Vis analysis showed that doping of ZrO2 with CuO significantly reduced its band gap from 4.61 eV to 1.18 eV, thus enhancing the utilization of visible light. The effect of catalyst dosage, doping ratio, and initial diesel concentration on the degradation rate of diesel was investigated by performing single-factor experiments. The optimization experiment results showed that 96.96% of diesel could be degraded under visible light. This study laid an experimental foundation for expanding the practical applications of photocatalytic technology.


Assuntos
Cobre/química , Luz , Nanocompostos/química , Poluição por Petróleo/análise , Poluentes Químicos da Água/análise , Zircônio/química , Catálise , Ecossistema , Recuperação e Remediação Ambiental , Modelos Teóricos , Oxirredução , Água do Mar/química
20.
Food Chem ; 331: 127277, 2020 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-32544653

RESUMO

A novel nanocomposite poly(ethylene-co-vinyl acetate) (EVA) film with controlled in vitro release of iprodione (ID) was prepared. Chitosan (CS) was used as the reinforcement which enhances the water and oxygen permeability of films. ID loaded poly(ethylene glycol)-poly(ε-caprolactone) (PEG-PCL) (IPP) micelles were used as the drug carrier which endows the films with antifungal and controlled release ability. IPP micelles with spherical shape and uniform size were obtained, and the maximum encapsulation efficacy (EE) was 91.17 ± 5.03% by well controlling the feeding amount of ID. Incorporation CS could improve the oxygen and moisture permeability of films, and the maximum oxygen permeability (OP) and water vapor transmission rate (WVTR) were 477.84 ± 13.03 cc/(m2·d·0.1 MPa) and 8.60 ± 0.25 g m-2 d-1, respectively. After loading IPP micelles, the films showed an improved antifungal ability and temperature-sensitive drug release behavior, and were found to enhance the quality of grapes by pre-harvest spraying.


Assuntos
Aminoimidazol Carboxamida/análogos & derivados , Hidantoínas/farmacocinética , Nanocompostos/química , Vitis/efeitos dos fármacos , Aminoimidazol Carboxamida/administração & dosagem , Aminoimidazol Carboxamida/farmacocinética , Quitosana/química , Preparações de Ação Retardada , Portadores de Fármacos , Microbiologia de Alimentos , Fungicidas Industriais/administração & dosagem , Fungicidas Industriais/farmacocinética , Hidantoínas/administração & dosagem , Lactonas/química , Micelas , Oxigênio , Permeabilidade , Polietilenoglicóis/química , Polivinil/química , Vapor
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