scholarly journals Visible-Light-Induced Bactericidal Activity of a Nitrogen-Doped Titanium Photocatalyst against Human Pathogens

2006 ◽  
Vol 72 (9) ◽  
pp. 6111-6116 ◽  
Author(s):  
Ming-Show Wong ◽  
Wen-Chen Chu ◽  
Der-Shan Sun ◽  
Hsuan-Shun Huang ◽  
Jiann-Hwa Chen ◽  
...  
Keyword(s):  
Antibacterial Activity ◽  
Visible Light ◽  
Bactericidal Activity ◽  
Uv Light ◽  
Shigella Flexneri ◽  
Light Illumination ◽  
Human Pathogens ◽  
Carbon Doped ◽  
Nitrogen Doped ◽  
Visible Light Illumination

ABSTRACT The antibacterial activity of photocatalytic titanium dioxide (TiO2) substrates is induced primarily by UV light irradiation. Recently, nitrogen- and carbon-doped TiO2 substrates were shown to exhibit photocatalytic activities under visible-light illumination. Their antibacterial activity, however, remains to be quantified. In this study, we demonstrated that nitrogen-doped TiO2 substrates have superior visible-light-induced bactericidal activity against Escherichia coli compared to pure TiO2 and carbon-doped TiO2 substrates. We also found that protein- and light-absorbing contaminants partially reduce the bactericidal activity of nitrogen-doped TiO2 substrates due to their light-shielding effects. In the pathogen-killing experiment, a significantly higher proportion of all tested pathogens, including Shigella flexneri, Listeria monocytogenes, Vibrio parahaemolyticus, Staphylococcus aureus, Streptococcus pyogenes, and Acinetobacter baumannii, were killed by visible-light-illuminated nitrogen-doped TiO2 substrates than by pure TiO2 substrates. These findings suggest that nitrogen-doped TiO2 has potential application in the development of alternative disinfectants for environmental and medical usages.

Photosensitization of Nitrogen Doped TiO2 Nanoparticles with Na-Chlorophyllin Copper for Degradation of Methyl Orange

2011 ◽  
Vol 343-344 ◽  
pp. 216-221
Author(s):  
Jian Yu Gong ◽  
Chang Zhu Yang ◽  
Wen Hong Pu ◽  
Jing Dong Zhang
Keyword(s):  
Methyl Orange ◽  
Visible Light ◽  
Light Illumination ◽  
Nitrogen Doped ◽  
Photoelectrocatalytic Degradation ◽  
Visible Light Illumination ◽  
Doped Titanium Dioxide ◽  
Degradation Properties ◽  
Degradation Of Methyl Orange ◽  
Nitrogen Doped Titanium Dioxide

Nitrogen doped titanium dioxide nanoparticals (N-TiO2) were prepared by the sol-hydrothermal method using urea as N sources. SEM showed the sphericity of as-prepared nanoparticals. XRD indicated that N-TiO2 was anatase crystal after thermal treatment. While Na-chlorophyllin copper (Na-chl-Cu) was used as to sensitize the N-TiO2, the photocurrent of Na-chl-Cu/N-TiO2 was 50 ìA double than that of N-TiO2 under visible light illumination. Thus, the visible light photoelectrocatalytic degradation properties of Na-chl-Cu/N-TiO2 were investigated using methyl orange (MO) as the objective pollution. When 1.8 V anodic bias potential and visible light were simultaneously applied, the highest degradation efficiency of MO over the Na-chl-Cu/N-TiO2 was obtained.

Enhanced photocatalytic disinfection of microorganisms by transition-metal-ion-modification of nitrogen-doped titanium oxide

2010 ◽  
Vol 25 (1) ◽  
pp. 167-176 ◽  
Author(s):  
Qi Li ◽  
Pinggui Wu ◽  
Rongcai Xie ◽  
Jian Ku Shang
Keyword(s):  
Transition Metal ◽  
Visible Light ◽  
Metal Ion ◽  
Photocatalytic Performance ◽  
Light Illumination ◽  
Transition Metal Ion ◽  
Nitrogen Doped ◽  
Carrier Recombination ◽  
Visible Light Illumination ◽  
Charge Carrier Recombination

In this article, palladium modification and silver modification were used as examples to demonstrate the disinfection effects on microorganisms in aqueous environment of photocatalytic transition-metal-ion-modified nitrogen-doped titanium oxide (TiON/M) materials. Transition metal ion modification was applied to TiON to take advantage of the coupling between transition metal ion addition and TiON semiconductor matrix under visible light illumination. The coupling promotes the separation of electron and hole pairs produced by photon excitation, thus it could reduce the intrinsic charge carrier recombination from anion-doping, which largely limits the photoactivity of TiON under visible light illumination. Large enhancements on the hydroxyl radical production and the photocatalytic disinfection efficiency on microorganisms under visible light illumination were observed for TiON with both palladium and silver modifications. The superior photocatalytic performance under visible light illumination suggests that the transition metal ion modification is an effective approach to reduce the massive charge carrier recombination from anion-doping and to enhance the photocatalytic performance of anion-doped TiO2. The resulting photocatalytic materials have the potential for a wide range of environmental applications.

scholarly journals Photocatalytic degradation of Direct yellow 86 diazo dye using sulfanilic acid-modified TiO2 in aqueous suspensions

2017 ◽  
Vol 76 (8) ◽  
pp. 1992-2002 ◽  
Author(s):  
Nafiseh Mansouriieh ◽  
Mahmoud Reza Sohrabi ◽  
Rogayyeh Pouramir Vajargah ◽  
Hasan Roudbaraki
Keyword(s):  
Visible Light ◽  
Uv Light ◽  
Removal Rate ◽  
Sulfanilic Acid ◽  
Light Illumination ◽  
Irradiation Intensity ◽  
Photodegradation Rate ◽  
Visible Light Illumination ◽  
Langmuir Isotherm Model ◽  
Diazo Dye

This study synthesized sulfanilic acid (SA)-modified TiO2 nanocomposites and used them as an effective photocatalyst for Direct yellow 86 diazo dye removal from aqueous solution. This novel nanocomposite (SA/TiO2) was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy and X-ray diffraction. The results showed the formation of SA/TiO2 nanocatalyst. The photocatalytic activity of the modified photocatalyst was examined by degradation of Direct yellow 86 (GE) under UV and visible light. The effects of five parameters, the concentration of GE, dosage of SA/TiO2 nanocomposite, UV light irradiation intensity, pH and visible light illumination, on the removal of GE using SA/TiO2 nanocomposite were studied. The highest GE removal was determined at pH of 9, nanocomposite dosage of 0.15 g/l and initial GE concentration of 50 mg/l at the constant temperature of 25 °C. However, the results showed that the GE removal rate increased as the UV light intensity increased. In addition, an enhancement in the photodegradation rate was observed with visible light illumination. The adsorption trends of GE at various initial concentrations followed the Langmuir isotherm model.

scholarly journals TiO2-rGO Composite for Photocatalytic Decolorization of Methylene Blue Under the Visible Light Illumination

2021 ◽  
Vol 9 (4) ◽  
pp. 167
Author(s):  
Ulfa Farizka Hidayati ◽  
Anthoni B. Aritonang ◽  
Lia Destiarti
Keyword(s):  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Visible Light ◽  
Uv Light ◽  
Bandgap Energy ◽  
Light Illumination ◽  
X Ray Diffraction ◽  
Visible Light Illumination ◽  
Blue Solution ◽  
Ft Ir

Titanium dioxide-reduced graphene oxide (TiO2-rGO) was synthesized by hydrothermal method using TiO2 powder and rGO precursor from graphite rod by modified Marcano Method. The obtained TiO2-rGO photocatalyst was characterized by X-Ray Diffraction (XRD), Fourier Transform Infrared Spectroscopy (FT-IR), and Diffuse reflectance UV (DRUV). Based on XRD diffractogram, it is known that TiO2 has an anatase crystal phase. In the FTIR spectrum, it was observed that there was an absorption peak at the wavenumber of 1630 cm-1 from the vibration (C=C) as an indication that the C atom was incorporated into the TiO2 structure. The incorporation of C atoms into the TiO2 structure to form TiO2-rGO causes the bandgap energy to decrease from 3.29 eV to 3.20 eV. The photocatalytic activity was tested against decolorization of methylene blue solution for 180 minutes under visible light illumination from a 50 watt LED lamp. Every 10 minutes, absorbance was measured using a UV-Vis spectrophotometer at a wavelength of 664 nm. TiO2-rGO photocatalyst has better photocatalytic activity with %D of 96.39% under UV light and 84.32% under visible light illumination, while TiO2 is only able to degrade 93.87% and 36.55%, respectively.

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