Methylene blue photocatalytic degradation under visible irradiation on TiO2 thin films sensitized with Cu and Zn tetracarboxy-phthalocyanines

2015 ◽  
Vol 299 ◽  
pp. 80-86 ◽  
Author(s):  
William Vallejo ◽  
Carlos Diaz-Uribe ◽  
Álvaro Cantillo
Keyword(s):  
Thin Films ◽  
Methylene Blue ◽  
Photocatalytic Degradation ◽  
Tio2 Thin Films ◽  
Visible Irradiation ◽  
Cu And Zn

Photocatalytic degradation of methylene blue from aqueous solutions using nanopillars-TiO2 thin films: Batch reactor studies

2018 ◽  
Vol 18 (3) ◽  
pp. 81-91 ◽  
Author(s):  
C. Lalhriatpuia
Keyword(s):  
Thin Films ◽  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Organic Carbon ◽  
Photocatalytic Degradation ◽  
Batch Reactor ◽  
Tio2 Thin Films ◽  
Initial Concentration ◽  
Bet Specific Surface Area ◽  
Interfering Ions

Nanopillars-TiO2 thin films was obtained on a borosilicate glass substrate with (S1) and without (S2) polyethylene glycol as template. The photocatalytic behaviour of S1 and S2 thin films was assessed inthe degradation of methylene blue (MB) dye from aqueous solution under batch reactor operations. The thin films were characterized by the SEM, XRD, FTIR and AFM analytical methods. BET specific surface area and pore sizes were also obtained. The XRD data confirmed that the TiO2 particles are in its anatase mineral phase. The SEM and AFM images indicated the catalyst is composed with nanosized pillars of TiO2, evenly distributed on the surface of the substrate. The BET specific surface area and pore sizes of S1 and S2 catalyst were found to be 5.217 and 1.420 m2/g and 7.77 and 4.16 nm respectively. The photocatalytic degradation of MB was well studied at wide range of physico-chemical parameters. The effect of solution pH (pH 4.0 to 10.0) and MB initial concentration (1.0 to 10.0 mg/L) was extensively studied and the effect of several interfering ions, i.e., cadmium nitrate, copper sulfate, zinc chloride, sodium chloride, sodium nitrate, sodium nitrite, glycine, oxalic acid and EDTA in the photocatalytic degradation of MB was demonstrated. The maximum percent removal of MB was observed at pH 8.0 beyond which it started decreasing and a low initial concentration of the pollutant highly favoured the photocatalytic degradation using thin films and the presence of several interfering ions diminished the photocatalytic activity of thin films to some extent. The overall photocatalytic activity was in the order: S2 > S1 > UV. The photocatalytic degradation of MB was followed the pseudo-first-order rate kinetics. The mineralization of MB was studied with total organic carbon measurement using the TOC (total organic carbon) analysis.

scholarly journals Methylene Blue Photodegradation under Visible Irradiation on Ag-Doped ZnO Thin Films

2020 ◽  
Vol 2020 ◽  
pp. 1-11 ◽  
Author(s):  
William Vallejo ◽  
Alvaro Cantillo ◽  
Carlos Díaz-Uribe
Keyword(s):  
Thin Films ◽  
Methylene Blue ◽  
Raman Spectroscopy ◽  
Photocatalytic Degradation ◽  
Physicochemical Characterization ◽  
Zno Thin Films ◽  
Visible Range ◽  
X Ray ◽  
Visible Irradiation ◽  
Doped Zno

This study synthesized and characterized Ag-doped ZnO thin films. Doped ZnO powders were synthesized using the sol-gel method, and thin films were fabricated using the doctor blade technique. The Ag content was determined by optical emission spectrometers with inductively coupled plasma (ICP plasma). Additionally, X-ray diffraction, Raman spectroscopy, Atomic Force Microscopy (AFM), diffuse reflectance, and X-ray photoelectron spectroscopy (XPS) measurements were used for physicochemical characterization. Finally, the photocatalytic degradation of methylene blue (MB) was studied under visible irradiation in aqueous solution. The Langmuir-Hinshelwood model was used to determine the reaction rate constant of the photocatalytic degradation. The physicochemical characterization showed that the samples were polycrystalline, and the diffraction signals corresponded to the ZnO wurtzite crystalline phase. Raman spectroscopy verified the ZnO doping process. The AFM analysis showed that roughness and grain size were reduced after the doping process. Furthermore, the optical results indicated that the presence of Ag improved the ZnO optical properties in the visible range, and the Ag-doped ZnO thin films had the lowest band gap value (2.95 eV). Finally, the photocatalytic degradation results indicated that the doping process enhanced the photocatalytic activity under visible irradiation, and the Ag-doped ZnO thin films had the highest MB photodegradation value (45.1%), as compared to that of the ZnO thin films (2.7%).

Comparative study of Ag, Sn or Zn doped TiO2 thin films for photocatalytic degradation of methylene blue and methyl orange

2019 ◽  
Vol 6 (10) ◽  
pp. 106435 ◽  
Author(s):  
Muhammad Kamran Tariq ◽  
Adeel Riaz ◽  
Ramsha Khan ◽  
Ahsan Wajid ◽  
Hamza-ul Haq ◽  
...  
Keyword(s):  
Thin Films ◽  
Methylene Blue ◽  
Methyl Orange ◽  
Comparative Study ◽  
Photocatalytic Degradation ◽  
Tio2 Thin Films ◽  
Doped Tio2

scholarly journals Cyanobacterial Biomass Pigments as Natural Sensitizer for TiO2 Thin Films

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Karen Patiño-Camelo ◽  
Carlos Diaz-Uribe ◽  
Euler Gallego-Cartagena ◽  
William Vallejo ◽  
Vincent Martinez ◽  
...  
Keyword(s):  
Thin Films ◽  
Methylene Blue ◽  
Stationary Phases ◽  
Blue Dye ◽  
Tio2 Thin Films ◽  
Wet Impregnation ◽  
Kinetic Information ◽  
Dry Biomass ◽  
Visible Irradiation ◽  
Cyanobacterial Biomass

In this work, we studied the effect of TiO2 sensitization with dry biomass extracted of cyanobacteria on the degradation of methylene blue dye (AM). Cyanobacterial cultures isolated from water samples were collected from the swamp of Malambo in Colombia; two main genera of cyanobacteria were identified, and they were cultivated with BG-11 culture medium. The concentrations of chlorophyll a in the exponential and stationary phases of growth were measured; the phycobilin content was quantified by spectrophotometry. Thin films of TiO2 were deposited by a doctor blade method, and they were sensitized by wet impregnation. Furthermore, a methylene blue (MB) photodegradation process was studied under visible light irradiation on the cyanobacterial biomass sensitized TiO2 material (TiO2/sensitizer); besides, the pseudo-first-order model was used to obtain kinetic information about photocatalytic degradation. The results showed that the BG-11+ treatment reported a higher amount of dry biomass and phycobiliproteins. After the sensitization process, the TiO2/sensitizer thin films showed a significant red shift in the optical activity; besides the thin film roughness decreasing, the TiO2/sensitizer showed photocatalytic activity of 23.2% under visible irradiation, and besides, the kinetic (kap) constant for TiO2/sensitizer thin films was 3.1 times greater than the kap value of TiO2 thin films. Finally, results indicated that cyanobacterial biomass is a suitable source of natural sensitizers to be used in semiconductor sensitization.

Photocatalytic degradation of methylene blue by the Anderson-type polyoxomolybdates/TiO2 thin films

Polyhedron ◽  
2018 ◽  
Vol 149 ◽  
pp. 163-170 ◽  
Author(s):  
Carlos E. Diaz-Uribe ◽  
Angie Rodríguez ◽  
Daniela Utria ◽  
William Vallejo ◽  
Esneyder Puello ◽  
...  
Keyword(s):  
Thin Films ◽  
Methylene Blue ◽  
Photocatalytic Degradation ◽  
Tio2 Thin Films

scholarly journals Synthesis of Nanoporous TiO2 Thin Films for Photocatalytic Degradation of Methylene Blue

2014 ◽  
Vol 17 (1) ◽  
pp. 023-028 ◽  
Author(s):  
M. Estrada ◽  
C. Reza ◽  
J. Salmones ◽  
J.A. Wang ◽  
M. E. Manríquez ◽  
...  
Keyword(s):  
Thin Films ◽  
Methylene Blue ◽  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Tio2 Films ◽  
Tio2 Thin Films ◽  
Direct Photolysis ◽  
Force Microscopy ◽  
Atomic Force ◽  
Surface Hydroxyls

This work reports a structure and photocatalytic activity of nanoporous titania (TiO2) thin films by an anodizing approach. Xray diffraction (XRD), scanning electron microscopy (SEM), and atomic force microscopy (AFM) studies showed that tetragonal anatase was the main phase in the thin films that consisted of countless disordered nanopores in the order of 10 to 15 nm. In the photocatalytic degradation of methylene blue, the titania thin films showed a good photocatalytic activity. 82.2 % methylene blue could be photodegraded by titania thin films with UV radiation. XPS results indicate that during the degradation of methylene blue, some Ti3+ may be partially oxidized to Ti4+ in the TiO2 films and the surface hydroxyls directly participate in the reaction. Our nanoporous titania thin films is commensurable to Degussa-25 TiO2 powders because the latter requires filtration in each treatment; it is also much superior to the direct photolysis approach with respect to photoactivity.

Use of Nanopillars-TiO2 Thin Films in the Photocatalytic Degradation of Bromophenol Blue from Aqueous Solution

2018 ◽  
Vol 6 (1) ◽  
pp. 22-30
Author(s):  
C. Lalhriatpuia ◽  
◽  
Thanhming liana ◽  
K. Vanlaldinpuia
Keyword(s):  
Thin Films ◽  
Aqueous Solution ◽  
Photocatalytic Activity ◽  
Photocatalytic Degradation ◽  
Batch Reactor ◽  
Bromophenol Blue ◽  
Tio2 Thin Films ◽  
Initial Concentration ◽  
Bet Specific Surface Area ◽  
Interfering Ions

The photocatalytic activity of Nanopillars-TiO2 thin films was assessed in the degradation of Bromophenol blue (BPB) dye from aqueous solution under batch reactor operations. The thin films were characterized by the XRD, SEM and AFM analytical methods. BET specific surface area and pore sizes were also obtained. The XRD data showed anatase phase of TiO2 particles with average particle size of 25.4 and 21.9 nm, for S1 and S2 catalysts respectively. The SEM and AFM images indicated the catalyst composed with Nanosized pillars of TiO2, evenly distributed on the surface of the substrate. The average height of the pillars was found to be 180 and 40 nm respectively for the S1 and S2 catalyst. The BET specific surface area and pore sizes of S1 and S2 catalyst were found to be 5.217 and 1.420 m2/g and 7.77 and 4.16 nm respectively. The photocatalytic degradation of BPB using the UV light was studied at wide range of physico-chemical parametric studies to determine the mechanism of degradation as well as the practical applicability of the technique. The batch reactor operations were conducted at varied pH (pH 4.0 to 10.0), BPB initial concentration (1.0 to 20.0 mg/L) and presence of several interfering ions, i.e., cadmium nitrate, copper sulfate, zinc chloride, sodium chloride, sodium nitrate, sodium nitrite, glycine, oxalic acid and EDTA in the photocatalytic degradation of BPB. The maximum percent removal of BPB was observed at pH 6.0 and a low initial concentration of the pollutant highly favours the photocatalytic degradation using thin films. The presence of several interfering ions suppressed the photocatalytic activity of thin films to some extent. The time dependence photocatalytic degradation of BPB was demonstrated with the pseudo-first-order rate kinetics. Study was further extended with total organic carbon measurement using the TOC (Total Organic Carbon) analysis. This demonstrated an apparent mineralization of BPB from aqueous solutions.

scholarly journals Efficient removal of 2-chlorophenol from aqueous solution using TiO2 thin films/alumina disc as photocatalyst by pulsed laser deposition

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
S. Ismat Shah ◽  
Sawsan A. Mahmoud ◽  
Samar H. Bendary ◽  
Ahmed K. Aboulgheit ◽  
A. A. Salem ◽  
...  
Keyword(s):  
Thin Films ◽  
Photocatalytic Degradation ◽  
Pulsed Laser Deposition ◽  
Catalyst Surface ◽  
Irradiation Time ◽  
Pulsed Laser ◽  
Textural Properties ◽  
Laser Deposition ◽  
Hydroxyl Groups ◽  
Tio2 Thin Films

AbstractPulsed laser deposition facilitates the epitaxial deposition and growth of TiO2 at low temperature on hot substrate. In this study, nanosized nitrogen-doped TiO2 thin films were deposited on fabricated alumina disc-shaped and glass substrates. Textural properties of the fabricated disc and alumina disc-supported TiO2 were investigated using N2 adsorption–desorption isotherms, field emission scanning electron microscopy (FESEM), X-ray diffraction and Fourier transform infrared (FTIR) spectroscopy. FESEM showed the presence of single crystals of TiO2 on the alumina disc. FTIR showed the presence of octahedral TiO2 and different hydroxyl groups on the surface which is responsible for the photoactivity and also showed the functional groups adsorbed on the catalyst surface after the photocatalytic degradation. The concentration of 2-chlorophenol and the photo-redox intermediate products as a function of irradiation time was determined. The concentration of the produced chloride ion during the photocatalytic degradation was determined by an ion chromatography. The results showed that the photocatalytic activity of the catalyst decreased upon cycling. The obtained results were compared with nanostructured TiO2 supported on glass substrate. Higher efficiency of 100% degradation was achieved for TiO2/Al2O3 catalyst, whereas about 70% degradation of 2-CP was achieved using TiO2/glass. Different photointermediates of 2-CP degradation have been identified for each cycle. The difference of intermediates is supported by the adsorbed fragments on the catalyst surface.

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