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1

Loading Effect of Ag Nanoparticles on Photocatalytic Activity of TiO2 Nanorod Arrays Prepared by Hydrothermal Method

Lee Kwangmin, Yoo Daeheung, Zakiyuddin Ahmad

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 3

751--754

EN

Rutile-TiO2 nanorod thin films were formed on Ti disks via alkali treatment in NaOH solutions followed by heat treatment at 700°C. Ag nanoparticles were loaded on nanorods using a photo-reduction method to improve the photocatalytic properties of the prepared specimen. The surface characterization and the photo-electrochemical properties of the Ag-loaded TiO2 nanorods were investigated using a field-emission scanning electron microscope (FE-SEM), X-ray photoelectron spectroscopy (XPS), UV-Vis spectroscopy and electrochemical impedance spectroscopy (EIS). The TiO2 nanorods obtained after the heat treatment were 80 to 180 nm thick and 1 μm long. The thickness of the nanorods increased with the NaOH concentration. The UV-Vis spectra exhibit a shift in the absorption edge of the Ag-loaded TiO2 to the visible light range and further narrowing of the bandgap. The decrease in the size of the capacitive loops in the EIS spectra showed that the Ag loading effectively improved the photocatalytic activity of the TiO2 nanorods.

2

Synthesis of antibacterial polyurethane film and its properties

Lin Zhao, Yunyun Li, Bin Cheng, Yu Chen

Polish Journal of Chemical Technology

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2020

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Vol. 22, nr 2

50--55

EN

Polyurethane (PU) is a polymer widely used in the biomedical field with excellent mechanical properties and good biocompatibility. However, it usually exhibits poor antibacterial properties for practical applications. Efforts are needed to improve the antibacterial activities of PU films for broader application prospect and added application values. In the present work, two PU films, TDI-P(E-co-T) and TDI-N-100-P(E-co-T), were prepared. Silver nanoparticles (AgNPs) were composited into the TDI-N-100-P(E-co-T) film for better mechanical properties and antibacterial activities, and resultant PU/AgNPs composite film was systematically characterized and studied. The as-prepared PU/AgNPs composite film exhibits much better antibacterial properties than the traditional PU membrane, exhibiting broader application prospect.

3

Enhanced Photocatalytic Properties of Ag-Loaded N-Doped Tio2 Nanotube Arrays

Gao D., Lu Z., Wang C., Li W., Dong P.

Autex Research Journal

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2018

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Vol. 18, no. 1

67--72

EN

Highly ordered TiO2 nanotube (TiO2 NT) arrays were prepared by anodic oxidizing method on the surface of the Ti substrate. Nitrogen-doped TiO2 nanotube (N-TiO2 NT) arrays were carried out by ammonia solution immersion, and Ag nanoparticles loaded N-doped TiO2 nanotube (Ag/N-TiO2 NT) arrays were obtained by successive ionic layer adsorption and reaction (SILAR) technique. The samples were characterized by the X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HRTEM), photoluminescence (PL) emission spectra, ultraviolet–visible (UV–vis) diffuse reflectance spectroscopy (DRS). The result indicated that the diameter and wall thickness of the TiO2 NT are 100–120 and 20–30 nm, respectively. Moreover, the morphology and structure of the highly ordered TiO2 NTs were not affected by N-doping. Furthermore, Ag nanoparticles were evenly deposited on the surface of TiO2 NTs in the form of elemental silver. Finally, the photocatalytic activity of Ag/N-TiO2 NTs was evaluated by degradation of methyl orange (MO) under visible-light irradiation. The Ag/N-TiO2 NTs exhibited enhanced photocatalytic properties, which could reach 95% after 90-min irradiation.

4

Characteristics of Silver Nanoparticles in Different pH Values

Mražíková A., Velgosová O., Kavuličová J., Matvija M., Čižmárová E., Willner J.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 2

993--998

EN

Stability of silver nanoparticles strongly influences the potential of their application. The literature shows wide possibilities of nanoparticles preparation, which has significantly impact on their properties. Therefore, the improvement of AgNPs preparation plays a key role in the case of their practical use. The pH values of the environment are one of the important factors, which directly influences stability of AgNPs. We present a comparing study of the silver nanoparticles prepared by „bottom-up“ methods over by chemical synthesis and biosynthesis using AgNO3 (0.29 mM) solution. For the biosynthesis of the silver nanoparticles, the green freshwater algae Parachlorella kessleri and Citrus limon extracts were used as reducing and stabilizing agents. Chemically synthesized AgNPs were performed using sodium citrate (0.5%) as a capping agent and 0.01% gelatine as a reducing agent. The formation and long term stability of those silver nanoparticles synthesized either biologically and chemically were clearly observed by solution colour changes and confirmed by UV-vis spectroscopy. The pH values of formed nanoparticle solutions were 3 and 5.8 for biosynthesized AgNPs using extract of Citrus limon and Parachlorella kessleri, respectively and 7.2 for chemically prepared AgNPs solution using citrate. The SEM as a surface imaging method was used for the characterization of nanoparticle shapes, size distribution and also for resolving different particle sizes. These micrographs confirmed the presence of dispersed and aggregated AgNPs with various shapes and sizes.

5

Formation and Antibacterial Property Analysis of Electrospun PVA Nonwoven Material with a Small Amount of Silver Nanoparticles

Pupkevičiūtė S., Adomavičiūtė E., Pavilonis A., Stanys S., Prosyčevas I.

Fibres & Textiles in Eastern Europe

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2015

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Vol. 23, no. 6 (114)

48--54

EN

Electrospinning is a process which produces nonwoven material from nano/microfibres. The aim of this study was to electrospin poly(vinyl alcohol) nano/microfibres material with small amount of silver nanoparticles (Ag-NPs), and estimate the influence of Ag-NPs on the structures and antibacterial properties of nonwoven materials. It was found that the Ag-NPs concentration does not have a significant influence on the viscosity and morphologies of electrospun materials. The addition of Ag-NPs causes the formation of thinner PVA nano/microfibres. The antibacterial activity test showed that a small amount of Ag-NPs provides antibacterial properties to electrospun PVA nano/microfibres. Antibacterial properties were tested with different bacteria: Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 12228, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Proteus mirabilis ATCC 12453, Bacillus cereus ATCC 11778 and Candida albicans ATCC 10231. It was also noticed that the concentration of Ag-NPs in nonwoven materials affects antibacterial properties. Clearly superior antibacterial properties were obtained from nonwoven materials with a higher concentration of Ag-NPs.

PL

Celem badań było wyprzędzenie włóknin z alkoholu poliwinylowego składających się z cienkich (nano-/mikro-) włókien zawierających małe ilości nanocząstek srebra. Badano wpływ ilości nanocząstek srebra na strukturę i właściwości antybakteryjne otrzymanych włóknin. Stwierdzono, że stężenie nanocząstek srebra nie wywiera istotnego wpływu na lepkość roztworu przędzącego i morfologię wyprzędzionych włókien. Dodatek mikrocząstek srebra prowadzi do otrzymania cieńszych włókien. Stwierdzono, że już małe ilości cząstek nanosrebra powodują uzyskanie właściwości antybakteryjnych. Badano je stosując następujące szczepy: Staphylococcus aureus ATCC 25923, Staphylococcus epidermidis ATCC 12228, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Proteus mirabilis ATCC 12453, Bacillus cereus ATCC 11778 and Candida albicans ATCC 10231. Stwierdzono również, że stężenie nanocząstek srebra we włóknach polepsza właściwości antybakteryjne.

6

Sposoby odzyskiwania metali szlachetnych z odpadów kopalnianych typu jarosytowego

Bednarczyk J., Sulej-Chojnacka J.

Obróbka Plastyczna Metali

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2012

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T. 23, nr 1

45-56

PL

W artykule przedstawiono cel oraz główne zadania projektu międzynarodowego ”Rozwój i zastosowanie nowych nanokompozytowych materiałów otrzymanych w recyklingu metali szlachetnych” realizowanego w Instytucie Obróbki Plastycznej w ramach 7. Programu Ramowego. W artykule przedstawiono metodę szybkiego rozkładu odpadu jarosytowego, który stanowi bazę surowcową w przedstawionym projekcie. Odpad jarosytowy poddano obróbce mechaniczno-chemicznej, celem odzyskania zawartego w nim srebra. W badaniach wykorzystano technologie, które zapewniają bezpieczeństwo ekologiczne i są ekonomiczne. Zastosowanie rozdrabniania w młynkach strumieniowych (jet mill) pozwoliło na uzyskanie ziaren o pożądanej wielkości oraz degradacje istniejących aglomeratów, natomiast przeprowadzony proces obróbki chemicznej w piecu fluidalnym spowodował zwiększenie zawartości srebra w odpadzie.

EN

This article presents the goal and main tasks of the international project "Development of New Nanocomposites Using Materials from Mining Industry" realized at the Metal Forming Institute within the frame of the 7th Framework Programme. A method of fast break-down of jarosite waste, which constitutes the source of raw materials in the project, has been presented in the article. Jarosite waste were subjected to mechanical and chemical processing for the purpose of recovering the silver contained in them. The studies apply technology that ensures ecological safety and are economically efficient. Disintegration in jet mills made it possible to obtain grains of the desired size and to degrade existing agglomerates, and the chemical process in a fluidized-bed furnace caused an increase in the silver content in the waste.

7

Charakterystyka warstw kompozytowych Ca-P/Ag/TiO2 na Ti do zastosowań biomedycznych

Roguska A., Pisarek M., Lewandowska M., Kurzydłowski K. J.

Inżynieria Materiałowa

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2012

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Vol. 33, nr 3

193--196

PL

Istotnym problemem w aplikacji implantów jest ryzyko infekcji pooperacyjnych, w dużym stopniu spowodowane przyleganiem bakterii do biomateriału. Celem przeprowadzonych prac jest wytworzenie nowoczesnych warstw kompozytowych typu Ca-P/Ag/TiO2 na podłożu tytanowym o dobrej biozgodności i właściwościach bakteriobójczych. Metodą utleniania anodowego wytworzono nanorurki TiO 2, które mają uporządkowaną strukturę, a ich wzrost odbywa się prostopadle do podłoża. Specyficzne rozwinięcie powierzchni nanorurek TiO 2 ułatwia tworzenie się warstw fosforanowo- -wapniowych (Ca-P). Osadzenie na tak przygotowanych podłożach odpowiedniej liczby nanocząstek srebra o średnicy 2÷50 nm metodą napylania w próżni ma zapewnić oczekiwane właściwości antyseptyczne. Warstwy kompozytowe na Ti składające się z powłoki ceramicznej i nanocząstek Ag powinny pozytywnie wpływać na aktywność osteoblastów oraz zapobiegać przyłączaniu się bakterii do powierzchni implantu.

EN

The new generation of medical implants made of titanium is functionalized with different coatings to improve their bioactivity and reduce the risk of infection. This paper describes how these goals can be achieved via the deposition of silver nanoparticles and calcium phosphate coating. TiO2 nanotubes were grown on a Ti substrate via electrochemical oxidation. Silver particles with a size of 2÷50 nm were deposited on the surface using the sputter deposition technique. It has been found that the silver nanoparticles are distributed homogeneously in the coating, which is promising to maintain a steady antibacterial effect. The results also show that the Ag-incorporated TiO2 nanotubes significantly stimulate apatite deposition from a Hanks’ solution. The highly ordered Ag-incorporated TiO 2 nanotube arrays with apatite coating may offer unique surface features of biomedical implants that assure both biocompatibility and antibacterial properties.

8

Properties and applications of silica submicron powders with surface Ag nanoclusters

Jasiorski M., Bakardijeva S., Doroszkiewicz W., Brzeziński S., Malinowska G., Ornat M., Stręk W., Maruszewski K.

Materials Science Poland

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2004

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Vol. 22, No. 2

137--144

EN

Spherical silica powders with uniform, submicron grain diameter have been obtained using the sol -gel technology. Subsequently, metallic silver nanoparticles have been produced on the surfaces of the grains. Raman scattering spectra of such SiO2-Ag0 powders impregnated in ethanol solutions of tris(2,2' -bipyridyl)ruthenium(II) can be recorded for solutions four orders of magnitude more diluted than the lowest possible concentration detectable for complex liquid solutions in the same experimental conditions (the SERS effect). Also, such silver-doped silica powders display anti-microbial capabilities and can be used to obtain doped thin-film coatings, e.g. for the production of bacteriostatic textiles.