scholarly journals Electrochemical Surface Biofunctionalization of Titanium through Growth of TiO2 Nanotubes and Deposition of Zn Doped Hydroxyapatite

Coatings ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 69
Author(s):  
Diana Maria Vranceanu ◽  
Elena Ungureanu ◽  
Ionut Cornel Ionescu ◽  
Anca Constantina Parau ◽  
Adrian Emil Kiss ◽  
...  
Keyword(s):  
Anatase Phase ◽  
Pure Titanium ◽  
Chemical Properties ◽  
Secondary Phase ◽  
Xrd Analysis ◽  
Electrochemical Treatment ◽  
Titania Nanotubes ◽  
Nanostructured Surface ◽  
Nanostructured Surfaces ◽  
Zn Content

The current research aim is to biofunctionalize pure titanium (Ti, grade IV) substrate with titania nanotubes and Zn doped hydroxyapatite-based coatings by applying a duplex electrochemical treatment, and to evaluate the influence of Zn content on the physico-chemical properties of hydroxyapatite (HAp). The obtained nanostructured surfaces were covered with HAp-based coatings doped with Zn in different concentrations by electrochemical deposition in pulsed galvanostatic mode. The obtained surfaces were characterized in terms of morphology, elemental and phasic composition, chemical bonds, roughness, and adhesion. The nanostructured surface consisted of titania nanotubes (NT), aligned, vertically oriented, and hollow, with an inner diameter of ~70 nm. X-Ray Diffraction (XRD) analysis showed that the nanostructured surface consists of an anatase phase and some rutile peaks as a secondary phase. The morphology of all coatings consisted of ribbon like-crystals, and by increasing the Zn content the coating became denser due to the decrement of the crystals’ dimensions. The elemental and phase compositions evidenced that HAp was successfully doped with Zn through the pulsed galvanostatic method on the Ti nanostructured surfaces. Fourier Transform Infrared spectroscopy (FTIR) and XRD analysis confirmed the presence of HAp in all coatings, while the adhesion test showed that the addition of a high quantity leads to some delamination. Based on the obtained results, it can be said that the addition of Zn enhances the properties of HAp, and through proper experimental design, the concentration of Zn can be modulated to achieve coatings with tunable features.

Cu Doped TiO2: Visible Light Assisted Photocatalytic Antimicrobial Activity and High Temperature Anatase Stability

2018 ◽  
Author(s):  
Snehamol Mathew ◽  
Priyanka Ganguly ◽  
Stephen Rhatigan ◽  
Vignesh Kumaravel ◽  
Ciara Byrne ◽  
...  
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Density Functional ◽  
Anatase Phase ◽  
Sol Gel ◽  
Chemical Properties ◽  
Light Irradiation ◽  
Health Concern ◽  
Bacterial Inactivation ◽  
X Ray

Indoor surface contamination by microbes is a major public health concern. A damp environment is one potential sources for microbe proliferation. Smart photocatalytic coatings on building surfaces using semiconductors like titania (TiO<sub>2</sub>) can effectively curb this growing threat.<b> </b>Metal-doped titania in anatase phase has been proved as a promising candidate for energy and environmental applications. In this present work, the antimicrobial efficacy of copper (Cu) doped TiO<sub>2 </sub>(Cu-TiO<sub>2</sub>) was evaluated against <i>Escherichia coli</i> (Gram-negative) and <i>Staphylococcus aureus</i> (Gram-positive) under visible light irradiation. Doping of a minute fraction of Cu (0.5 mol %) in TiO<sub>2 </sub>was carried out <i>via</i> sol-gel technique. Cu-TiO<sub>2</sub> further calcined at various temperatures (in the range of 500 °C – 700 °C) to evaluate the thermal stability of TiO<sub>2</sub> anatase phase. The physico-chemical properties of the samples were characterised through X-ray diffraction (XRD), Raman spectroscopy, X-ray photo-electron spectroscopy (XPS) and UV-visible spectroscopy techniques. XRD results revealed that the anatase phase of TiO<sub>2</sub> was maintained well, up to 650 °C, by the Cu dopant. UV-DRS results suggested that the visible light absorption property of Cu-TiO<sub>2 </sub>was enhanced and the band gap is reduced to 2.8 eV. Density functional theory (DFT) studies emphasises the introduction of Cu<sup>+</sup> and Cu<sup>2+</sup> ions by replacing Ti<sup>4+</sup> ions in the TiO<sub>2</sub> lattice, creating oxygen vacancies. These further promoted the photocatalytic efficiency. A significantly high bacterial inactivation (99.9%) was attained in 30 mins of visible light irradiation by Cu-TiO<sub>2</sub>.

Physico-chemical properties of titania nanotubes synthesized via hydrothermal and annealing treatment

2011 ◽  
Vol 258 (1) ◽  
pp. 431-435 ◽  
Author(s):  
Leo Bey Fen ◽  
Tan Kim Han ◽  
Ng Meng Nee ◽  
Bee Chin Ang ◽  
Mohd Rafie Johan
Keyword(s):  
Chemical Properties ◽  
Annealing Treatment ◽  
Titania Nanotubes ◽  
Physico Chemical

scholarly journals Synthesis of Zinc Oxide Supported on Titanium Dioxide for Photocatalytic Oxidative Desulfurization of Dibenzothiophene

2018 ◽  
Vol 1 (1) ◽  
Author(s):  
Hitam, C.N.C. ◽  
Jalil, A.A. ◽  
Triwahyono, S.
Keyword(s):  
Zinc Oxide ◽  
Titanium Dioxide ◽  
High Efficiency ◽  
Diffuse Reflectance Spectroscopy ◽  
Anatase Phase ◽  
Oxidative Desulfurization ◽  
Xrd Analysis ◽  
X Ray Diffraction ◽  
Desulfurization Rate ◽  
Low Energy Consumption

Photocatalytic oxidative desulfurization (PODS) has received much attention due to low energy consumption and high efficiency, as well as simple and pollution-free operation. In this study, zinc oxide supported on titanium dioxide (ZnO/TiO2) catalysts were prepared via a simple electrochemical method. The presence of anatase phase TiO2 and wurtzite ZnO was confirmed by X-ray diffraction (XRD) analysis while band gap energies were determined by UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS). The photocatalytic activity was tested for desulfurization of 100 mg/L dibenzothiophene (DBT). The highest desulfurization rate (2.20 × 10-3 mM/min) was achieved using 1 g/L of 10 wt% ZnO/TiO2 after 2 hr under UV irradiation.

Effect of Zn content on cytoactivity and bacteriostasis of micro-arc oxidation coatings on pure titanium

2013 ◽  
Vol 228 ◽  
pp. S428-S432 ◽  
Author(s):  
B.H. Zhao ◽  
W. Zhang ◽  
D.N. Wang ◽  
W. Feng ◽  
Y. Liu ◽  
...  
Keyword(s):  
Pure Titanium ◽  
Zn Content ◽  
Micro Arc Oxidation

Preparation and Dielectric Property of Al2O3 Surface Coating Modified BaTiO3/Polyimide Composite Film

2014 ◽  
Vol 908 ◽  
pp. 63-66
Author(s):  
Ya Jun Wang ◽  
Xiao Juan Wu ◽  
Chang Gen Feng
Keyword(s):  
Dielectric Constant ◽  
Barium Titanate ◽  
Composite Film ◽  
Breakdown Strength ◽  
In Situ Polymerization ◽  
Chemical Properties ◽  
Dielectric Strength ◽  
Xrd Analysis ◽  
Nanocomposite Films ◽  
The Matrix

Polyimide (PI) was chosen as the matrix of the composite, barium titanate/polyimide (BT/PI) nanocomposite films were prepared by in situ polymerization. In order to improve the dispersion and the physical-chemical properties of BT surface, barium titanate was modified by Al2O3coating and modified BT/PI nanocomposite films were prepared. The prepared modified BT was characterized by X-ray diffraction (XRD) analysis, and scanning electron microscopy (SEM), and the dielectric properties of the composites were characterized in detail. It was shown that surface modification with Al2O3is the chemical process and there were new substances forming. When BT was modified by 10 wt% Al2O3, the dielectric constant of the composite film was 18.96 (103Hz), the loss tangent 0.005, breakdown strength 70 MV·m-1, energy storage density 0.41 J·cm-3. The dielectric constant of BT modified by Al2O3is decreased while the dielectric strength of the modified BT/PI composite film is increased.

Structural and Optical Characterization of Synthesized TiO2 Nanopowder Using Sol–Gel Technique

2016 ◽  
Vol 15 (01n02) ◽  
pp. 1650002 ◽  
Author(s):  
S. Lourduraj ◽  
R. Victor Williams
Keyword(s):  
Anatase Phase ◽  
Sol Gel ◽  
Visible Spectrum ◽  
Average Crystallite Size ◽  
Xrd Analysis ◽  
Force Microscopy ◽  
Morphological Studies ◽  
Atomic Force ◽  
Gel Technique

The nanocrystalline TiO2 powder was synthesized by sol–gel method. The XRD analysis reveals that TiO2 powder was highly crystalline (anatase phase) and nanostructured with tetragonal system. The average crystallite size after calcined at 673[Formula: see text]K is found to be 7.7[Formula: see text]nm. The surface morphological studies using scanning electron microscopy (SEM) exhibit that the formation of nanosized TiO2 particles with less densification nature. Atomic force microscopy (AFM) topography exhibits the uniform distribution of spherical-shaped particles. The energy dispersive X-ray spectroscopy (EDX) confirms the presence of Titanium and Oxygen in synthesized TiO2 nanopowder. The value of optical bandgap of TiO2 nanopowder calculated from UV-Visible spectrum is 3.45[Formula: see text]eV. The presence of TiO2 particles is confirmed from the dominant fourier transform infrared (FTIR) peaks at 621[Formula: see text]cm[Formula: see text] and 412[Formula: see text]cm[Formula: see text].

Heat Transfer Enhancement Effect of Nanostructured Surface Made of Carbon Nanotube on SiC Ceramics

2013 ◽  
Author(s):  
Hiroki Noguchi
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Heat Transfer Enhancement ◽  
Chemical Vapor ◽  
Enhancement Effect ◽  
Nanostructured Surface ◽  
Transfer Enhancement ◽  
Energy Agency ◽  
Nanostructured Surfaces ◽  
Surface Decomposition

The Japan Atomic Energy Agency (JAEA) has been conducting research and development on the thermo-chemical iodine–sulfur (IS) process, which is one of the most attractive water-splitting hydrogen production methods using the nuclear heat of a high-temperature gas-cooled reactor (HTGR). In researching this IS process, a silicon carbide (SiC) heat exchanger with good corrosion resistance was used in a corrosive situation in boiling sulfuric acid. With the aim of enhancing heat transfer in the SiC heat exchanger, a nanostructured surface made of carbon nanotubes (CNTs) was produced on a SiC substrate by surface decomposition. Two types of SiC, one produced by pressureless sintering (PLS-SiC) and one by chemical vapor deposition (CVD-SiC), were used as substrates. CNTs formed by the surface decomposition of SiC can vary depending on the crystal structure of the substrates. Additionally, in order to investigate surface wettability, nanostructured surfaces on the CVD-SiC with hydrophilicity and hydrophobicity were produced. The effects of heat transfer enhancement by the nanostructured surfaces were evaluated by a convective heat transfer test using de-ionized water. The nanostructured surface on the CVD-SiC with hydrophilicity was the only surface that showed any heat transfer enhancement. However, this enhancement was much smaller than those previously reported. The experiment showed that the small size of the nanopores influenced the heat transfer enhancement and that the wettability of the nanostructured surface was related to heat transfer enhancement.

Comparison of Droplet Evaporation and Nucleate Boiling Mechanisms on Nanoporous Superhydrophilic Surfaces

2019 ◽  
Author(s):  
Samuel Cabrera ◽  
Van P. Carey
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Heat Transfer Performance ◽  
Pool Boiling ◽  
Nucleate Boiling ◽  
Droplet Evaporation ◽  
Transfer Performance ◽  
Nanostructured Surface ◽  
Nanostructured Surfaces ◽  
Droplet Vaporization

Abstract Recent studies have indicated that at slightly superheated surface temperatures, droplet evaporation on a nanoporous superhydrophilic surface exhibits onset of nucleation and nucleate boiling effects similar to pool boiling processes. This paper discusses water droplet evaporation experiments and pool boiling experiments conducted on nanostructured surfaces of a 45° downward facing pyramid copper and aluminum substrate. The nanostructured surfaces were used to conduct both droplet evaporation experiments and pool boiling experiments and thus allow direct comparison of the underlying heat transfer performance and mechanisms for these two different processes. The four surfaces tested were the following: bare copper surface, nanostructured surface on copper, bare aluminum surface, and nanostructured surface on aluminum. Mean heat flux values at varying superheats were obtained through temperature and time measurements. To better understand the heat performance of each surface, the wetting and wicking characteristics of each surface were also tested. Experimental results indicate that many of the mechanisms associated with pool boiling may also play a role in droplet vaporization, and their presence can produce levels of heat transfer performance comparable to, or even higher than, that observed in pool boiling at a comparable wall superheat. The results demonstrate that the nanostructured surface affects onset of nucleate boiling and maximum heat flux in both droplet vaporization and nucleate boiling on these surfaces. The implications of these results for strategies to enhance spray cooling and pool boiling are also discussed.

Effect of Cobalt Content on the Structural Properties of Zirconia Prepared by Sol-Gel Method

2020 ◽  
Vol 1000 ◽  
pp. 227-232
Author(s):  
Nurhayati Indah Ciptasari ◽  
Adri Nora ◽  
Lutviasari Nuraini ◽  
Lusiana ◽  
Nono Darsono ◽  
...  
Keyword(s):  
Structural Properties ◽  
Sol Gel ◽  
Cobalt Content ◽  
Secondary Phase ◽  
Xrd Analysis ◽  
Weight Percent ◽  
Sem Images ◽  
Monoclinic Crystal ◽  
Gel Method ◽  
Sol Gel Method

Zirconia (ZrO2) powders doped with cobalt were prepared by sol-gel method using inorganic salt of zirconium (IV) chloride (ZrCl4) as precursor. The amount of cobalt was varied in the range of 4–16% weight percent to study the effect to structural properties. X-ray diffraction (XRD) analysis suggested the resulting phases were zirconium oxide (Baddeleyite) with monoclinic crystal system along with cobalt oxide as secondary phase. The increasing cobalt content caused the XRD peaks to shift into lower angle due to substitution of Zr atom to smaller Co atom in crystal lattice. Scanning electron microscope (SEM) images showed the samples with higher Co content had smoother surface. Generally, the microstructures of Co doped zirconia powders consisted of large agglomerates with small particles on the surface.

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