A composite of clay, cement, and wood as natural support material for the immobilization of commercial titania (P25, P90, PC500, C-TiO2) towards photocatalytic phenol degradation

Abstract Different types of commercial titania (P25, P90, PC500, and C-TiO2) were immobilized as single or mixed photocatalyst onto the surface of a natural support material made of cement, clay, and wood fibers. The successful immobilization was studied by different techniques showing a composite material with the mechanical properties of the support material and the photocatalytic behavior of the immobilized titania. The supported photocatalyst showed high mechanical stability and was applied to the photocatalytic degradation of phenol as a model pollutant under UV light irradiation. As the most active photocatalytic material, a mixture PC500 and P90 (comp-PC500/P90) was identified with an apparent pseudo first-order kinetic rate constant (kapp) of 0.010 min−1 at a degradation efficiency of 100%. The catalyst was used several times and showed minor loss in activity during four runs due to degradation intermediates adsorbed to the surface, shown by a color change from white to yellow.

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Improved Photocatalyzed Degradation of Phenol, as a Model Pollutant, over Metal-Impregnated Nanosized TiO2

Nanomaterials ◽

10.3390/nano10050996 ◽

2020 ◽

Vol 10 (5) ◽

pp. 996 ◽

Cited By ~ 2

Author(s):

S. Belekbir ◽

M. El Azzouzi ◽

A. El Hamidi ◽

L. Rodríguez-Lorenzo ◽

J. Arturo Santaballa ◽

...

Keyword(s):

Mechanical Stability ◽

Diffuse Reflectance Spectroscopy ◽

Compressive Strain ◽

Phenol Degradation ◽

Relative Pressure ◽

Order Kinetic ◽

X Ray ◽

Toc Removal ◽

Type Iv ◽

Vis Spectroscopy

Photocatalyzed degradation of phenol in aqueous solution over surface impregnated TiO2 (M = Cu, Cr, V) under UV-Vis (366 nm) and UV (254 nm) irradiation is described. Nanosized photocatalyts were prepared from TiO2-P25 by wet impregnation, and characterized by X-ray diffraction, X-ray fluorescence, transmission electron microscopy, UV-Vis diffuse reflectance spectroscopy, Raman spectroscopy, and adsorption studies. No oxide phases of the metal dopants were found, although their presence in the TiO2-P25 lattice induces tensile strain in Cu-impregnated TiO2-P25, whereas compressive strain in Cr- and V-impregnated TiO2-P25. Experimental evidences support chemical and mechanical stability of the photocatalysts. Type IV N2 adsorption–desorption isotherms, with a small H3 loop near the maximum relative pressure were observed. Metal surface impregnated photocatalysts are mesoporous with a similar surface roughness, and a narrow pore distribution around ca. 25 Å. They were chemically stable, showing no metal lixiviation. Their photocatalytic activity was followed by UV-Vis spectroscopy and HPLC–UV. A first order kinetic model appropriately fitted the experimental data. The fastest phenol degradation was obtained with M (0.1%)/TiO2-P25, the reactivity order being Cu > V >> Cr > TiO2-P25 under 366 nm irradiation, while TiO2-P25 > Cu > V > Cr, when using 254 nm radiation. TOC removal under 366 nm irradiation for 300 min showed almost quantitative mineralization for all tested materials, while 254 nm irradiation for 60 min led to maximal TOC removal (ca. 30%). Photoproducts and intermediate photoproducts were identified by HPLC–MS, and appropriate reaction pathways are proposed. The energy efficiency of the process was analysed, showing UV lamps are superior to UVA lamps, and that the efficiency of the surface impregnated catalyst varies in the order Cu > V > Cr.

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Electron microscopy of keratinocytes cultured on a collagen substrate used as an allograft for the treatment of chronic wounds

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100130158 ◽

1992 ◽

Vol 50 (2) ◽

pp. 1104-1105

Author(s):

Debby A. Jennings ◽

Michael J. Morykwas ◽

Louis C. Argenta

Keyword(s):

Electron Microscopy ◽

Cell Suspension ◽

Single Cell ◽

Chronic Wounds ◽

Mechanical Stability ◽

Uv Light ◽

Type I ◽

Single Cell Suspension ◽

Collagen Substrate ◽

Dermal Collagen

Grafts of cultured allogenic or autogenic keratlnocytes have proven to be an effective treatment of chronic wounds and burns. This study utilized a collagen substrate for keratinocyte and fibroblast attachment. The substrate provided mechanical stability and augmented graft manipulation onto the wound bed. Graft integrity was confirmed by light and transmission electron microscopy.Bovine Type I dermal collagen sheets (100 μm thick) were crosslinked with 254 nm UV light (13.5 Joules/cm2) to improve mechanical properties and reduce degradation. A single cell suspension of third passage neonatal foreskin fibroblasts were plated onto the collagen. Five days later, a single cell suspension of first passage neonatal foreskin keratinocytes were plated on the opposite side of the collagen. The grafts were cultured for one month.The grafts were fixed in phosphate buffered 4% formaldehyde/1% glutaraldehyde for 24 hours. Graft pieces were then washed in 0.13 M phosphate buffer, post-fixed in 1% osmium tetroxide, dehydrated, and embedded in Polybed 812.

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Deposition of Zinc Oxide Coatings on Wood Surfaces Using the Solution Precursor Plasma Spraying Process

Coatings ◽

10.3390/coatings11020183 ◽

2021 ◽

Vol 11 (2) ◽

pp. 183

Author(s):

Ghiath Jnido ◽

Gisela Ohms ◽

Wolfgang Viöl

Keyword(s):

Zinc Oxide ◽

Ftir Spectroscopy ◽

Photoelectron Spectroscopy ◽

Color Change ◽

Uv Light ◽

Beech Wood ◽

Nitrate Solution ◽

Ftir Spectra ◽

Solution Precursor ◽

Wood Surfaces

In the present work, the solution precursor plasma spray (SPPS) process was used to deposit zinc oxide (ZnO) coatings on wood surfaces using zinc nitrate solution as precursor to improve the hydrophobicity and the color stability of European beech wood under exposure to ultraviolet (UV) light. The surface morphology and topography of the wood samples and the coatings were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The formation of ZnO was detected with the help of X-ray photoelectron spectroscopy (XPS) and by Fourier transform infrared (FTIR) spectroscopy. The FTIR spectra of the coated samples showed the typical Zn–O band at 445 cm−1. According to the XPS analysis, the coatings consist of two different Zn-containing species: ZnO and Zn(OH)2. Variation of the deposition parameters showed that the most significant parameters affecting the microstructure of the coating were the solution concentration, the deposition scan speed, and carrier gas flow rate. The wettability behaviors of the coated wood were evaluated by measuring the water contact angle (WCA). The coatings that completely covered the wood substrates showed hydrophobic behaviors. UV-protection of wood surfaces after an artificial UV light irradiation was evaluated by color measurements and FTIR spectroscopy. The ZnO-coated wood surfaces were more resistant to color change during UV radiation exposure. The total color change decreased up to 60%. Additionally, the FTIR spectra showed that the wood surfaces coated with ZnO had more stability. The carbonyl groups formation and C=C-bonds consumption were significantly lower.

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Recrystallization of CsPbBr3 Nanoparticles in Fluoropolymer Nonwoven Mats for Down- and Up-Conversion of Light

Nanomaterials ◽

10.3390/nano11020412 ◽

2021 ◽

Vol 11 (2) ◽

pp. 412

Author(s):

Vladimir Neplokh ◽

Daria I. Markina ◽

Maria Baeva ◽

Anton M. Pavlov ◽

Demid A. Kirilenko ◽

...

Keyword(s):

Mechanical Stability ◽

Uv Light ◽

Visible Spectral Range ◽

High Quantum Yield ◽

Environmental Robustness ◽

Nonwoven Mats ◽

Down Conversion ◽

Green Photoluminescence ◽

Significant Attention ◽

Narrow Emission

Inorganic halides perovskite CsPbX3 (X = Cl, Br, and I or mixed halide systems Cl/Br and Br/I) nanoparticles are efficient light-conversion objects that have attracted significant attention due to their broadband tunability over the entire visible spectral range of 410–700 nm and high quantum yield of up to 95%. Here, we demonstrate a new method of recrystallization of CsPbBr3 nanoparticles inside the electrospun fluoropolymer fibers. We have synthesized nonwoven tetrafluoroethylene mats embedding CsPbBr3 nanoparticles using inexpensive commercial precursors and syringe electrospinning equipment. The fabricated nonwoven mat samples demonstrated both down-conversion of UV light to 506 nm and up-conversion of IR femtosecond laser radiation to 513 nm green photoluminescence characterized by narrow emission line-widths of 35 nm. Nanoparticle formation inside nonwoven fibers was confirmed by TEM imaging and water stability tests controlled by fluorimetry measurements. The combination of enhanced optical properties of CsPbBr3 nanoparticles and mechanical stability and environmental robustness of highly deformable nonwoven fluoropolymer mats is appealing for flexible optoelectronic applications, while the industry-friendly fabrication method is attractive for commercial implementations.

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Destruction of Pollutants and Microorganisms in Water by UV Light and Hydrogen Peroxide

Water Quality Research Journal ◽

10.2166/wqrj.1992.004 ◽

1992 ◽

Vol 27 (1) ◽

pp. 57-68 ◽

Cited By ~ 8

Author(s):

D.W. Sundstrom ◽

B.A. Weir ◽

T. A. Barber ◽

H. E. Klei

Keyword(s):

Hydrogen Peroxide ◽

Organic Compounds ◽

Chemical Structure ◽

Uv Light ◽

Liquid Films ◽

Strong Interactions ◽

Order Kinetic ◽

E Coli ◽

Order Kinetic Model ◽

Catalyzed Oxidation

Abstract This project investigated the destruction of organic compounds and microorganisms in water by ultraviolet catalyzed oxidation using hydrogen peroxide as the oxidizing agent. The combination of UV light and hydrogen peroxide was effective in decomposing all of the organic compounds studied. The rates of destruction increased with increasing peroxide concentration and UV light intensity, and were highly dependent on chemical structure. The destruction of mixtures of organic compounds showed strong interactions between reacting components. The inactivation of E. coli and B. subtilis spores by UV light and/or hydrogen peroxide was studied in flat plate reactors. By using thin liquid films, the combination of UV light and peroxide greatly increased the rates of inactivation of both microorganisms. The results were correlated by a mixed second order kinetic model.

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High-intensity focused ultrasound-induced mechanochemical transduction in synthetic elastomers

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1901047116 ◽

2019 ◽

Vol 116 (21) ◽

pp. 10214-10222 ◽

Cited By ~ 9

Author(s):

Gun Kim ◽

Vivian M. Lau ◽

Abigail J. Halmes ◽

Michael L. Oelze ◽

Jeffrey S. Moore ◽

...

Keyword(s):

High Intensity ◽

Cellular Response ◽

Focused Ultrasound ◽

Focal Spot ◽

Color Change ◽

Uv Light ◽

High Intensity Focused Ultrasound ◽

Photon Flux ◽

Mechanical Stimuli ◽

Mechanochemical Transduction

While study in the field of polymer mechanochemistry has yielded mechanophores that perform various chemical reactions in response to mechanical stimuli, there is not yet a triggering method compatible with biological systems. Applications such as using mechanoluminescence to generate localized photon flux in vivo for optogenetics would greatly benefit from such an approach. Here we introduce a method of triggering mechanophores by using high-intensity focused ultrasound (HIFU) as a remote energy source to drive the spatially and temporally resolved mechanical-to-chemical transduction of mechanoresponsive polymers. A HIFU setup capable of controlling the excitation pressure, spatial location, and duration of exposure is employed to activate mechanochemical reactions in a cross-linked elastomeric polymer in a noninvasive fashion. One reaction is the chromogenic isomerization of a naphthopyran mechanophore embedded in a polydimethylsiloxane (PDMS) network. Under HIFU irradiation evidence of the mechanochemical transduction is the observation of a reversible color change as expected for the isomerization. The elastomer exhibits this distinguishable color change at the focal spot, depending on ultrasonic exposure conditions. A second reaction is the demonstration that HIFU irradiation successfully triggers a luminescent dioxetane, resulting in localized generation of visible blue light at the focal spot. In contrast to conventional stimuli such as UV light, heat, and uniaxial compression/tension testing, HIFU irradiation provides spatiotemporal control of the mechanochemical activation through targeted but noninvasive ultrasonic energy deposition. Targeted, remote light generation is potentially useful in biomedical applications such as optogenetics where a light source is used to trigger a cellular response.

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Rewritable Spiropyran/Polyacrylonitrile Hybrid Nanofiber Membrane Prepared by Electrospinning

NANO ◽

10.1142/s1793292020500137 ◽

2020 ◽

Vol 15 (01) ◽

pp. 2050013 ◽

Cited By ~ 1

Author(s):

Bingwei Bao ◽

Ji Fan ◽

Rui Xu ◽

Wei Wang ◽

Dan Yu

Keyword(s):

Color Change ◽

Uv Light ◽

Dimethyl Fumarate ◽

Gravimetric Analysis ◽

Nanofiber Membrane ◽

Good Thermal Stability ◽

Fast Switching ◽

Hybrid Nanofiber ◽

Nanofiber Film ◽

Photochromic Materials

Photochromic materials aroused enormous interest due to their potential application for rewritable paper, smart labeling and sensor devices. In this paper, we proposed to dissolve spiropyran (SP, photochromic material) and polyacrylonitrile (PAN, polymer matrix) in dimethyl fumarate (DMF) to prepare photochromic nanofibers by electrospinning. The target SP compounds were featured by FTIR, ultraviolet (UV) and 1HNMR, and the nanofibers were characterized by FTIR, UV-vis spectra, scanning electron microscope (SEM), thermal gravimetric analysis (TGA) and contact angle (CA). The test results demonstrated that photochromic SP was synthesized successfully, and the nanofiber membrane possesses extraordinary color-converting properties including obvious color change from white to purple, reversible fast switching between two colors when exposed to UV light and achieve maximum color change in 1[Formula: see text]min, and switchable hydrophilic and hydrophobic properties as well as excellent photo-fatigue resistance over 20 cycles. In addition, it has good thermal stability allowing it to be used under harsh conditions. In view of the above characteristics, we believe that the as-prepared nanofiber film will be a promising reusable writing substrate.

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UV Irradiated Graphene-Based Nanocomposites: Change in the Mechanical Properties by Local HarmoniX Atomic Force Microscopy Detection

Materials ◽

10.3390/ma12060962 ◽

2019 ◽

Vol 12 (6) ◽

pp. 962 ◽

Cited By ~ 2

Author(s):

Liberata Guadagno ◽

Carlo Naddeo ◽

Marialuigia Raimondo ◽

Vito Speranza ◽

Roberto Pantani ◽

...

Keyword(s):

Mechanical Properties ◽

Atomic Force Microscopy ◽

Mechanical Stability ◽

Uv Light ◽

Ultra Violet ◽

Graphene Nanoplatelets ◽

Free Standing ◽

Force Microscopy ◽

Atomic Force ◽

Acquisition Mode

Epoxy based coatings are susceptible to ultra violet (UV) damage and their durability can be significantly reduced in outdoor environments. This paper highlights a relevant property of graphene-based nanoparticles: Graphene Nanoplatelets (GNPs) incorporated in an epoxy-based free-standing film determine a strong decrease of the mechanical damages caused by UV irradiation. The effects of UV light on the morphology and mechanical properties of the solidified nanocharged epoxy films are investigated by Atomic Force Microscopy (AFM), in the acquisition mode “HarmoniX.” Nanometric-resolved maps of the mechanical properties of the multi-phase material evidence that the incorporation of low percentages, between 0.1% and 1.0% by weight, of graphene nanoplatelets (GNPs) in the polymeric film causes a relevant enhancement in the mechanical stability of the irradiated films. The beneficial effect progressively increases with increasing GNP percentage. The paper also highlights the potentiality of AFM microscopy, in the acquisition mode “HarmoniX” for studying multiphase polymeric systems.

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Effect of 172-nm UV irradiation on polyimide and its application in surface modification by grafting

High Performance Polymers ◽

10.1177/0954008319897315 ◽

2020 ◽

Vol 32 (7) ◽

pp. 761-774

Author(s):

Lopamudra Das ◽

John C Poutsma ◽

Michael J Kelley

Keyword(s):

Uv Irradiation ◽

Photoelectron Spectroscopy ◽

Secondary Ion Mass Spectrometry ◽

Mechanical Stability ◽

Uv Light ◽

Force Microscopy ◽

Angle Measurements ◽

Wide Range ◽

Grafting Reactions ◽

Sample Position

Polyimides (PIs) have a wide range of industrial and scientific applications due to their excellent thermal and mechanical stability and chemical resistance. Their response to ultraviolet (UV) irradiation is of further interest in high-value applications such as spacecraft technology and electronics packaging. In this work, we investigated the effect of 172-nm UV xenon excimer lamp irradiation on samples of pyromellitimido-oxydianiline (PMDA-ODA) commercial films in the absence of oxygen. The average irradiance received at the sample position was 90 mW/cm2, and the total radiation dosage varied from 0 to 64 J/cm2. X-Ray photoelectron spectroscopy, time-of-flight-secondary ion mass spectrometry, atomic force microscopy, and contact angle measurements were used to characterize the effect. Calculated UV-visible spectroscopy absorption spectra were obtained using the ZINDO//B3LYP/3-21G method to give an indication of which orbitals are involved in the transitions near 172 nm. The reactivity of the different UV-treated PI samples toward nitrogen-borne heptafluorodecene vapor was then investigated using the above techniques. Grafting reactions occurred on the surface of the photochemically activated polymer. This study explored the potential for modification of PI surfaces using UV-light-assisted grafting to impart valuable functionalities.

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UV Light Assisted Coating Method of Polyphenol Caffeic Acid and Mediated Immobilization of Metallic Silver Particles for Antibacterial Implant Surface Modification

Polymers ◽

10.3390/polym11071200 ◽

2019 ◽

Vol 11 (7) ◽

pp. 1200 ◽

Cited By ~ 5

Author(s):

Ji Yeon Lee ◽

Ludwig Erik Aguilar ◽

Chan Hee Park ◽

Cheol Sang Kim

Keyword(s):

Caffeic Acid ◽

Mechanical Stability ◽

Uv Light ◽

Oxidative Polymerization ◽

Titanium Implants ◽

Metallic Silver ◽

Functional Coatings ◽

Implant Surface ◽

Coating Application

Titanium implants are extensively used in biomedical applications due to their excellent biocompatibility, corrosion resistance, and superb mechanical stability. In this work, we present the use of polycaffeic acid (PCA) to immobilize metallic silver on the surface of titanium materials to prevent implant bacterial infection. Caffeic acid is a plant-derived phenolic compound, rich in catechol moieties and it can form functional coatings using alkaline buffers and with UV irradiation. This combination can trigger oxidative polymerization and deposition on the surface of metallic substrates. Using PCA can also give advantages in bone implants in decreasing inflammation by decelerating macrophage and osteoclast activity. Here, chemical and physical properties were investigated using FE-SEM, EDS, XPS, AFM, and contact angle. The in vitro biocompatibility and antibacterial studies show that PCA with metallic silver can inhibit bacterial growth, and proliferation of MC-3T3 cells was observed. Therefore, our results suggest that the introduced approach can be considered as a potential method for functional implant coating application in the orthopedic field.

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