Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 88
Filtrar
Mais filtros










Intervalo de ano de publicação
1.
Int J Biol Macromol ; 273(Pt 2): 133203, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38885860

RESUMO

This study investigates the performance of biopolymer electrolytes based on chitosan and dextran for energy storage applications. The optimization of ion transport and performance of electric double-layer capacitors EDCL using these electrolytes, incorporating different concentrations of glycerol as a plasticizer and TiO2 as nanoparticles, is explored. Impedance measurements indicate a notable reduction in charge transfer resistance with the addition of TiO2. DC conductivity estimates from AC spectra plateau regions reach up to 5.6 × 10-4 S/cm. The electric bulk resistance Rb obtained from the Nyquist plots exhibits a substantial decrease with increasing plasticizer concentration, further enhanced by the addition of the nanoparticles. Specifically, Rb decreases from ∼20 kΩ to 287 Ω when glycerol concentration increases from 10 % to 40 % and further drops to 30 Ω with the introduction of TiO2. Specific capacitance obtained from cyclic voltammetry shows a notable increase as the scan rate decreases, indicating improved efficiency and stability of ion transport. The TiO2-enriched EDCL achieves 12.3 F/g specific capacitance at 20 mV/s scan rate, with high ion conductivity and extended electrochemical stability. These results suggest the great potential of plasticizer and TiO2 with biopolymers in improving the performance of energy storage systems.


Assuntos
Quitosana , Dextranos , Eletrólitos , Transporte de Íons , Titânio , Titânio/química , Quitosana/química , Eletrólitos/química , Dextranos/química , Capacitância Elétrica , Condutividade Elétrica , Plastificantes/química
2.
Heliyon ; 10(9): e30765, 2024 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-38765064

RESUMO

Light-driven water splitting has gained increasing attention as an eco-friendly method for hydrogen production. There is a pressing need to enhance the performance of catalysts for the commercial viability of this reaction. Many methods have been proposed to improve catalyst performance; however, an economical and straightforward approach remains a priority. This paper presents an uncomplicated technique called acid treatment, which augments the catalytic performance of nanoparticles. The method promotes a change in the catalytic reactivity by causing a deficit in electron density of Ti and O on the surface of TiO2 nanoparticles without altering their size, morphology, or crystal structure. In the Eosin Y sensitized photocatalytic hydrogen production system, nitric acid treated TiO2 (16.95 µmol/g) exhibited 1.5 times the hydrogen production compared to bare TiO2 (11.15 µmol/g).

3.
Environ Monit Assess ; 196(6): 552, 2024 May 16.
Artigo em Inglês | MEDLINE | ID: mdl-38755295

RESUMO

The TiO2 nanocomposite efficiency was determined under optimized conditions with activated carbon to remove ammoniacal nitrogen (NH3-N) from the leachate sample. In this work, the facile impregnation and pyrolysis synthesis method was employed to prepare the nanocomposite, and their formation was confirmed using the FESEM, FTIR, XRD, and Raman studies. In contrast, Raman phonon mode intensity ratio ID/IG increases from 2.094 to 2.311, indicating the increase of electronic conductivity and defects with the loading of TiO2 nanoparticles. The experimental optimal conditions for achieving maximum NH3-N removal of 75.8% were found to be a pH of 7, an adsorbent mass of 1.75 mg/L, and a temperature of 30 °C, with a corresponding time of 160 min. The experimental data were effectively fitted with several isotherms (Freundlich, Hill, Khan, Redlich-Peterson, Toth, and Koble-Corrigan). The notably elevated R2 value of 0.99 and a lower ARE % of 14.61 strongly support the assertion that the pseudo-second-order model compromises a superior depiction of the NH3-N reduction process. Furthermore, an effective central composite design (CCD) of response surface methodology (RSM) was employed, and the lower RMSE value, precisely 0.45, demonstrated minimal disparity between the experimentally determined NH3-N removal percentages and those predicted by the model. The subsequent utilization of the desirability function allowed us to attain actual variable experimental conditions.


Assuntos
Carvão Vegetal , Nitrogênio , Titânio , Poluentes Químicos da Água , Titânio/química , Nitrogênio/química , Poluentes Químicos da Água/química , Poluentes Químicos da Água/análise , Carvão Vegetal/química , Amônia/química , Adsorção , Modelos Químicos , Eliminação de Resíduos Líquidos/métodos , Nanocompostos/química
4.
J Basic Microbiol ; 64(6): e2300680, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38381060

RESUMO

The anthracene biodegradation potential of Serratia quinivorans HP5 was studied under a controlled laboratory environment. The green TiO2 nanoparticles (NPs) synthesized from Paenibacillus sp. HD1PAH was used to accelerate the biodegradation process. The synergistic application of TiO2 NPs and S. quinivorans HP5 resulted in a reduction of anthracene concentration by 1.2 folds in liquid-medium and 1.5 folds in contaminated soil. Gas-chromatography and mass-spectrometric investigation showed the production of four anthracene derivatives, namely 1,2-anthracene dihydrodiol, 6,7-benzocoumarin, anthrone, and 9,10-anthraquinoneat the termination of experimental periods. Furthermore, bacterial biomass increased by 23.3 folds in the presence of TiO2 NPs, and overall soil enzyme activities were enhanced by 4.2 folds in the treated samples. In addition, there was a negative correlation observed between the biomass of S. quinivorans HP5 and the concentrations of anthracene, suggesting the involvement of bacterium in anthracene biodegradation processes. The degradation pathway of anthracene revealed its transformation into the less toxic compound 9,10-anthraquinone. Overall, this study elucidates a novel biodegradation pathway for anthracene and highlights the potential of nano-assisted bacterial remediation as a promising approach for environmental cleanup.


Assuntos
Antracenos , Antraquinonas , Biodegradação Ambiental , Serratia , Titânio , Antracenos/metabolismo , Serratia/metabolismo , Titânio/química , Titânio/metabolismo , Antraquinonas/metabolismo , Antraquinonas/química , Biomassa , Nanopartículas/química , Paenibacillus/metabolismo , Poluentes do Solo/metabolismo , Microbiologia do Solo
5.
Environ Toxicol ; 39(3): 1388-1401, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-37986241

RESUMO

Silver is usually loaded on nano-titanium dioxide (TiO2 ) through photodeposition method to enhance visible-light catalytic functions for environment purification. However, little is known about how the toxicity changes after silver doping and how the physicochemical properties of loaded components affect nanocomposite toxicity. In this study, Ag-TiO2 with different sizes and contents of silver particles were obtained by controlling photodeposition time (PDT) and silver addition amount. Pro-inflammatory and pro-fibrogenic responses of these photocatalysts were evaluated in male C57BL/6J murine lung. As a result, silver was well assembled on TiO2 , promoting visible-light catalytic activity. Notably, the size of silver particles increased with PDT. Meanwhile, toxicity results showed that pure TiO2 (P25) mainly caused neutrophil infiltration, while 2 wt/wt% silver-loaded TiO2 recruited more types of inflammatory cells in the lung. Both of them caused the increase of proinflammatory cytokines while decreasing the anti-inflammatory cytokine in bronchoalveolar lavage fluid. However, 2 wt/wt% silver doping also accelerated the lung pro-fibrogenic response of photocatalysts in the subacute phase from evidence of collagen deposition and hydroxyproline concentrations. Mechanistically, the overactivation of TGFBR2 receptors in TGF-ß/smads pathways by silver-loaded TiO2 rather than pure TiO2 may be the reason why silver-loaded TiO2 can promote pro-fibrogenic effect response. Intriguingly, the increased toxicity caused by silver doping can be rescued by increasing the size of the loaded silver or decreasing the silver amount. These results may be important for the new understanding of the toxicity of TiO2 -based photocatalysts.


Assuntos
Nanopartículas Metálicas , Prata , Camundongos , Masculino , Animais , Prata/química , Nanopartículas Metálicas/química , Pulmão , Líquido da Lavagem Broncoalveolar , Titânio/química , Citocinas
6.
Environ Sci Pollut Res Int ; 30(43): 98020-98033, 2023 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-37603240

RESUMO

In vitro drought stress has a considerable impact on the mass production of active compounds in medicinal plants. Nevertheless, photosynthesis, nutrient uptake, and protein synthesis may be negatively affected by drought, which results in poor growth. Titanium dioxide nanoparticles (TiO2 NPs) have recently been shown to play an important role in increasing nutrient uptake, resistance to various environmental stresses, and better plant growth. Regarding the importance of pharmaceutical metabolites of Melissa officinalis L., this experiment aimed to assess the role of TiO2 NPs in improving physiological responses and phytochemical properties in M. officinalis under in vitro drought stress. For this, two-week-old seedlings were cultured on Murashige and Skoog (MS) medium supplemented with 0, 50, and 100 mg L-1 TiO2 NPs and 0, 3, and 6% (w/v) polyethylene glycol (PEG). Two weeks after treatments, a reduction of chlorophyll, protein content, essential elements, and enhancement of H2O2 and malondialdehyde (MDA) levels were seen as a result of drought stress. It was observed that M. officinalis partially responded to the drought by increasing non-enzymatic antioxidants, including phenolics, flavonoids, and anthocyanin and ascorbate peroxidase activity. Moreover, PEG-induced drought stress increased some important essential oil content such as limonene, alpha-pinene, myrcene, γ-3-carene, citral, and carvacrol; however, the results showed that TiO2 NPs not only increased the quantity of essential oils but also led to tolerance to the drought stress by increasing photosynthetic pigments, antioxidant systems, absorption of essential nutrients, and decreasing H2O2 and MDA levels.


Assuntos
Melissa , Óleos Voláteis , Óleos Voláteis/farmacologia , Antioxidantes , Plântula , Secas , Peróxido de Hidrogênio
7.
Micromachines (Basel) ; 14(7)2023 Jul 21.
Artigo em Inglês | MEDLINE | ID: mdl-37512774

RESUMO

Titanium dioxide has attracted a great deal of attention in the field of environmental purification due to its photocatalytic activity under ultraviolet light. Photocatalytic efficiency and the energy required to initiate the process remain the drawbacks that hinder the widespread adoption of the process. Consistently with this, it is proposed here the polymerization of hexamethyldisiloxane fragments simultaneously to TiO2 sputtering for the production of thin films in low-pressure plasma. The effect of plasma excitation power on the molecular structure and chemical composition of the films was evaluated by infrared spectroscopy. Wettability and surface energy were assessed by a sessile drop technique, using deionized water and diiodomethane. The morphology and elemental composition of the films were determined using scanning electron microscopy and energy dispersive spectroscopy, respectively. The thickness and roughness of the resulting films were measured using profilometry. Organosilicon-to-silica films, with different properties, were deposited by combining both deposition processes. Titanium was detected from the structures fabricated by the hybrid method. It has been observed that the proportion of titanium and particles incorporated into silicon-based matrices depends on the plasma excitation power. In general, a decrease in film thickness with increasing power has been observed. The presence of Ti in the plasma atmosphere alters the plasma deposition mechanism, affecting film deposition rate, roughness, and wettability. An interpretation of the excitation power dependence on the plasma activation level and sputtering yield is proposed. The methodology developed here will encourage researchers to create TiO2 films on a range of substrates for their prospective use as sensor electrodes, water and air purification systems, and biocompatible materials.

8.
Sci Total Environ ; 901: 165875, 2023 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-37517725

RESUMO

The controlled synthesis of silver nanoparticles (AgNPs) decorated TiO2 nanohybrids (Ag/TiO2) for photocatalysis has received considerable attention. These photocatalysts are widely used in environment and energy, resulting in human exposure through inhalation. Pure TiO2 is generally considered a low-toxic nanomaterial. However, little is known about the toxicity after AgNPs loading. In this study, silver-decorated TiO2 nanohybrids were controllably synthesized by the photodeposition method, and their toxic effects on murine lung and human lung epithelial cells were explored. As a result, silver loading significantly enhanced the effect of TiO2 photocatalyst on EMT in lung epithelial cells, potentially acting as a pro-fibrogenic effect in murine lung. Meanwhile, the increase in autophagy vacuoles, LC3-II marker, stub-RFP-sens-GFP-LC3 fluorescence assay, and LC3 turnover assay showed that silver loading also significantly increased autophagy flux. Furthermore, analysis of autophagy inhibition by 3-Methyladenine indicated that the promotion of EMT by silver loading was related to the increased autophagy flux. Intriguingly, the autophagy and EMT biological effects could be alleviated when the silver loading amount was reduced or silver particle size was increased, and the enhanced pro-fibrogenic effect was mitigated at the same time. This study supplemented safety information of Ag-decorated TiO2 nanohybrids and provided methods of controlled synthesis for reducing toxicity.

9.
Bull Environ Contam Toxicol ; 110(6): 101, 2023 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-37278734

RESUMO

This study compared effects of low concentrations (0.05 and 0.1 mg/L) of nano-TiO2 and bulk-TiO2 on brain, gill and liver acetylcholinesterase (AChE) and erythrocytic DNA of Nile tilapia over 7 and 14 days exposure. Both TiO2 forms did not affect brain AChE activities. Bulk-TiO2 induced elevation of gill AChE activities only after 7 days while nano-TiO2 had no effect. Liver AChE activities were increased by 0.1 mg/L bulk- and nano-TiO2 to similar extents. At 7 days, erythrocytic DNA damage was induced only by 0.1 mg/L nano- and bulk-TiO2 to similar extents, but damage was not repaired to control levels at 7 days recovery period. At 14 days continuous exposure, DNA damage was induced by 0.05, 0.1 mg/L nano-TiO2 and 0.1 mg/L of bulk-TiO2 to similar extents. Results show that both forms of TiO2 can pose genotoxic hazards to fish populations under sub-chronic exposure. However, their neurotoxic potential was not evident.


Assuntos
Ciclídeos , Animais , Acetilcolinesterase/metabolismo , Ciclídeos/genética , Dano ao DNA , Estresse Oxidativo , Titânio/toxicidade
10.
Sci Total Environ ; 857(Pt 2): 159689, 2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36302435

RESUMO

Elevated CO2 affects the plant rhizosphere and can therefore affect the fate and toxicity of soil contaminants. However, little is known about how the effects of nanoparticles on plants and soil bacteria will change under future CO2 levels. A free-air CO2 enrichment system with two CO2 levels (ambient, 390 µmol mol-1; elevated, 590 µmol mol-1) was used to investigate the responses of rice (Oryza sativa L.) and soil bacteria to titanium dioxide nanoparticles (nano-TiO2, 0 and 200 mg kg-1). Results showed that nano-TiO2 alone did not significantly affect rice growth but affected soil bacteria involved in the carbon and sulfur cycles. Elevated CO2 alone increased rice plant biomass and up-regulated genes related to ribosomes, but its combination with nano-TiO2 down-regulated genes related to photosynthesis and photosynthetic antennae. Elevated CO2 also exacerbated the disturbance by nano-TiO2 to soil bacteria involved in carbon and nitrogen cycles, and consequently inhibited the rice growth. These findings provide a reference for the comprehensive evaluation for the risk of soil pollution.


Assuntos
Nanopartículas , Oryza , Solo , Dióxido de Carbono/análise , Transcriptoma , Folhas de Planta/química , Carbono , Nanopartículas/toxicidade , Bactérias
11.
Environ Toxicol Pharmacol ; 98: 104043, 2023 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-36565896

RESUMO

This study evaluated potential genotoxic and histopathological effects of nano-TiO2 (0.1, 0.5 and 1 mg/L) in Nile tilapia over 7, 14 and 21 days of exposure. Bulk TiO2 (1 mg/L) along with controls was used for comparison. Comet assay revealed that nano-TiO2 can induce erythrocytic DNA damage in a concentration dependent manner. However, micronuclei induction was observed only at the lowest concentration. Elevated organ damage indices indicate nano-TiO2 induced histological alterations in liver and intestine. Severe histological alterations induced by nano-TiO2 in the fish were necrosis of hepatic parenchyma and intestinal mucosa. Bulk TiO2 exposure had no effect on the histological structure of the intestine but increased liver damage indices and erythrocytic DNA damage compared to the controls indicating dissolved form of TiO2 is not biologically inert. More research efforts are needed to generate in vivo toxicity data on realistic levels of nano-TiO2 and bulk TiO2 for environmental risk assessments.


Assuntos
Ciclídeos , Animais , Ciclídeos/genética , Dano ao DNA , Ensaio Cometa , Titânio/toxicidade
12.
Environ Sci Pollut Res Int ; 30(7): 18522-18534, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36215003

RESUMO

Titanium dioxide (TiO2) nanoparticles interact with organic-inorganic pollutants in the environment, and these interactions affect their environmental behavior. The mechanisms of the interaction between TiO2 and organic-inorganic pollutants on the surface of clay minerals are still unclear. In this work, isotherm adsorption was studied to explore the interactions between Cd2+/tetracycline (TC), TiO2 nanoparticles, and a zeolite (Zeo). SEM, FT-IR, and XPS were also used to reveal the interaction mechanism between organic-inorganic pollutants and TiO2 on their stability and mobility in the environment. Compared to the single systems, the adsorption of Cd2+ and TiO2 in the Cd + TiO2 composite system decreased by 3.43% and 9.90%, respectively; the TC and TiO2 adsorption in the TC + TiO2 composite system decreased by 14.39% and 45.47%, respectively. The antagonism between Cd2+ and TiO2 was due to Cd2+ and TiO2 competing for the electrostatic attraction (-OH) and hydrogen bonding sites (Si-O), and TC and TiO2 competing for the hydrogen bonding sites (-OH and C = O) on Zeo. The presence of TiO2 will increase the mobility of Cd2+ and TC on a clay surface, and this effect is more significant for organic pollutants TC. Compared with Cd2+, TC has a more significant boosting impact on the TiO2 mobility.


Assuntos
Poluentes Ambientais , Poluentes Químicos da Água , Zeolitas , Cádmio , Argila , Espectroscopia de Infravermelho com Transformada de Fourier , Tetraciclina , Antibacterianos , Titânio , Adsorção
13.
Mar Environ Res ; 183: 105826, 2023 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-36427438

RESUMO

Compounds in sunscreen such as ultraviolet (UV) filters protect human skin from damage caused by UV radiation exposure. However, sunscreen components reach marine ecosystems after their release from human skin during activities such as swimming and washing, and are potentially toxic to marine organisms. TiO2 and ZnO nanoparticles (NPs) are commonly used as inorganic UV filters. In this study, we explored the effects of TiO2 and ZnO NPs on natural phytoplankton assemblages in coastal seawater. Growth rates of natural phytoplankton assemblages were significantly decreased by 10 mg L-1 TiO2 and 1 and 10 mg L-1 ZnO NP treatments. NP addition also modified the size structure of phytoplankton assemblages, and small phytoplankton (mainly cyanobacteria) are vulnerable to NPs. Because herbivore food preferences depend strongly on algal cell size, NP contamination could also affect higher trophic levels. Notably, small phytoplankton are an important component in microbial loop, and this energy transfer pathway may be more vulnerable to NP contamination.


Assuntos
Fitoplâncton , Óxido de Zinco , Humanos , Óxido de Zinco/toxicidade , Óxido de Zinco/química , Protetores Solares , Ecossistema , Titânio/toxicidade , Água do Mar/química
14.
Luminescence ; 38(7): 999-1010, 2023 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35997211

RESUMO

Nanomaterials are gaining enormous interests due to their novel applications that have been explored nearly in every field of our contemporary society. In this scenario, preparations of nanomaterials following green routes have attracted widespread attention in terms of sustainable, reliable, and environmentally friendly practices to produce diverse nanostructures. In this review, we summarize the fundamental processes and mechanisms of green synthesis approaches of TiO2 nanoparticles (NPs). We explore the role of plants and microbes as natural bioresources to prepare TiO2 NPs. Particularly, focus has been made to explore the potential of TiO2 -based nanomaterials to design a variety of sensing platforms by exploiting the photocatalysis efficiency under the influence of a light source. These types of sensing are of massive importance for monitoring environmental pollution and therefore for inventing advanced strategies to remediate hazardous pollutants and offer a clean environment.


Assuntos
Nanopartículas , Nanoestruturas , Nanotecnologia , Nanoestruturas/química , Poluição Ambiental
15.
Polymers (Basel) ; 14(20)2022 Oct 21.
Artigo em Inglês | MEDLINE | ID: mdl-36298042

RESUMO

Mangium (Acacia mangium Willd.) is a fast-growing wood that is widely grown in Indonesia. The impregnation method is needed to improve the qualities of the wood. In this study, TiO2 nanoparticle (79.17 nm) was produced using the hydrothermal method. The purpose of this study was to analyze the effect of TiO2 nanoparticle impregnation on the density and dimensional stability of mangium and the effectiveness of the presence of TiO2 nanoparticle in wood in degrading pollutants. The mangium samples (2 cm × 2 cm × 2 cm) were placed inside impregnation tube. The impregnation solutions included water (untreated), 1% TiO2 nanoparticle, and 5% TiO2 nanoparticles. The samples were analyzed for density, weight percent gain (WPG) dan bulking effect (BE). Samples were also analyzed by X-ray diffraction (XRD) and Fourier-transform infrared spectroscopy (FTIR). TiO2 nanoparticle resulted in an increase in density, WPG, and BE-treated mangium. Based on XRD and FTIR results, TiO2 nanoparticle was successfully impregnated into mangium wood. Scanning electron microscopy-energy-dispersive X-ray spectroscopy analysis indicated that TiO2 nanoparticle covered the surface of the wood cells. The TiO2-impregnated mangium wood has a higher photocatalyst activity than untreated, indicating better protection from UV radiation and pollutants.

16.
Environ Sci Pollut Res Int ; 29(47): 70706-70745, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36044146

RESUMO

The rapid population growth and industrial expansion worldwide have created serious water contamination concerns. To curb the pollution issue, it has become imperative to use a versatile material for the treatment. Titanium dioxide (TiO2) has been recognized as the most-studied nanoparticle in various fields of science and engineering due to its availability, low cost, efficiency, and other fascinating properties with a wide range of applications in modern technology. Recent studies revealed the photocatalytic activity of the material for the treatment of industrial effluents to promote environmental sustainability. With the wide band gap energy of 3.2 eV, TiO2 can be activated under UV light; thus, many strategies have been proposed to extend its photoabsorption to the visible light region. In what follows, this has generated increasing attention to study its characteristics and structural modifications in different forms for photocatalytic applications. The present review provides an insight into the understanding of the synthesis methods of TiO2, the current progress in the treatment techniques for the degradation of wide environmental pollutants employing modified TiO2 nanoparticles, and the factors affecting its photocatalytic activities. Further, recent developments in using titania for practical applications, the approach for designing novel nanomaterials, and the prospects and opportunities in this exciting area have been discussed.


Assuntos
Poluentes Ambientais , Nanopartículas , Purificação da Água , Catálise , Luz , Titânio/química , Água
17.
Nanomaterials (Basel) ; 12(14)2022 Jul 11.
Artigo em Inglês | MEDLINE | ID: mdl-35889590

RESUMO

Formaldehyde (HCHO) is a ubiquitous indoor pollutant that seriously endangers human health. The removal of formaldehyde effectively at room temperature has always been a challenging problem. Here, a kind of amino-fullerene derivative (C60-EDA)-modified titanium dioxide (C60-EDA/TiO2) was prepared by one-step hydrothermal method, which could degrade the formaldehyde under solar light irradiation at room temperature with high efficiency and stability. Importantly, the introduction of C60-EDA not only increases the adsorption of the free formaldehyde molecules but also improves the utilization of sunlight and suppresses photoelectron-hole recombination. The experimental results indicated that the C60-EDA/TiO2 nanoparticles exhibit much higher formaldehyde removal efficiency than carboxyl-fullerene-modified TiO2, pristine TiO2 nanoparticles, and almost all other reported formaldehyde catalysts especially in the aspect of the quality of formaldehyde that is treated by catalyst with unit mass (mHCHO/mcatalyst = 40.85 mg/g), and the removal efficiency has kept more than 96% after 12 cycles. Finally, a potential formaldehyde degradation pathway was deduced based on the situ diffuse reflectance infrared Fourier transform spectrometry (DRIFTS) and reaction intermediates. This work provides some indications into the design and fabrication of the catalysts with excellent catalytic performances for HCHO removal at room temperature.

18.
Int J Biol Macromol ; 213: 145-154, 2022 Jul 31.
Artigo em Inglês | MEDLINE | ID: mdl-35636530

RESUMO

To improve the postharvest quality and reduce the anthracnose of bananas, the sodium alginate (SA)/tea tree essential oil nanoemulsion (TEON) based bilayer films incorporated with different contents of TiO2 nanoparticles were fabricated in this work. The developed TEON presented satisfactory DPPH scavenging activity (65.5 ± 1.8%) and antifungal capability (90.5 ± 5.8%). The microscopy images of the cross-section of the films indicated that the bilayer films with well-cross-linked were developed successfully. Notably, the addition of a certain content of TiO2 to SA greatly improved the UV blocking and water vapor and oxygen barrier properties of the developed film. However, the barrier property of the film was decreased when the TiO2 content further increased to 4.0 mg/100 mg of SA. The retention of TEO under visible and UV light in the bilayer film was respectively prolonged to 24 days and 32 h when the addition of TiO2 content was 2.0 mg/100 mg of SA. Finally, the postharvest quality and anthracnose of banana fruits were significantly improved by SA-TiO2 + SA-TEON film-forming solution treatments. Results from the present work might open up new insights into the approaches of postharvest quality improvement of bananas.


Assuntos
Musa , Nanopartículas , Óleo de Melaleuca , Alginatos , Embalagem de Alimentos , Chá , Titânio , Árvores
19.
Polymers (Basel) ; 14(8)2022 Apr 08.
Artigo em Inglês | MEDLINE | ID: mdl-35458269

RESUMO

This study aimed to evaluate the colour stability of polymethyl methacrylate (PMMA) denture base reinforced with ZrO2 nanoparticles, E-glass fibres, and TiO2 nanoparticles at various concentrations over 180-day storage in Steradent™ (STD) denture cleaner or coffee (CF). A total of 130 disc-shaped specimens were fabricated at various filler concentrations and divided into four main groups to measure the colour changes. Groups Z, T, and E consisted of PMMA reinforced with ZrO2 nanoparticles, TiO2 nanoparticles, or E-glass fibre, respectively, while Group C consisted of PMMA specimens without filler served as the control group (n = 10). The three reinforced groups were further subdivided according to the filler content (n = 10) added to the PMMA (1.5%, 3.0%, 5.0%, and 7.0% wt.%). Half of the specimens were stored in STD, while the other half was stored in CF for 180 days. A Minolta Chroma Meter was used to measure the colour changes (ΔE) at 7, 30, 90 and then 180 days. The results were assessed using two-way repeated-measures analysis of variance (RM-ANOVA) along with Bonferroni post hoc tests at a p ≤ 0.05 significance level. Significant different colour changes (ΔΕ) were observed between all tested groups and across different time points. TiO2-reinforced PMMA in STD/CF showed the lowest colour stability, while the E-glass fibre-reinforced PMMA in STD/CF showed the highest colour stability. Furthermore, coffee appeared to have the greatest impact on the colour change in comparison to the SteradentTM. The results indicated that the filler type and concentration, type of solution, and length of storage all affected the colour stability of the tested specimens.

20.
Int J Mol Sci ; 23(7)2022 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-35408812

RESUMO

A series of poly(ethylene-co-vinyl alcohol)/titanium dioxide (PEVAL/TiO2) nanocomposites containing 1, 2, 3, 4 and 5 wt% TiO2 were prepared by the solvent casting method. These prepared hybrid materials were characterized by Fourier-transform infrared (FT-IR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). The pores and their interconnections inside these nanocomposites were created using naphthalene microparticles used as a porogen after having been extracted by sublimation under a high vacuum at temperatures slightly below the glass transition temperature. A cellular activity test of these hybrid materials was performed on human gingival fibroblast cells (HGFs) in accordance with ISO 10993-5 and ISO 10993-12 standards. The bioviability (cell viability) of HGFs was evaluated after 1, 4 and 7 days using Alamar Blue®. The results were increased cell activity throughout the different culture times and a significant increase in cell activity in all samples from Day 1 to Day 7, and all systems tested showed significantly higher cell viability than the control group on Day 7 (p < 0.002). The adhesion of HGFs to the scaffolds studied by SEM showed that HGFs were successfully cultured on all types of scaffolds.


Assuntos
Nanocompostos , Engenharia Tecidual , Etilenos , Humanos , Nanocompostos/química , Polietileno , Espectroscopia de Infravermelho com Transformada de Fourier , Engenharia Tecidual/métodos , Titânio/química , Titânio/farmacologia , Difração de Raios X
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...