Methylene blue photocatalytic mineralization under visible irradiation on TiO2 thin films doped with chromium

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.

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

Science Vision ◽

10.33493/scivis.18.03.01 ◽

2018 ◽

Vol 18 (3) ◽

pp. 81-91 ◽

Cited By ~ 1

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.

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Epitaxy of Porous and Photocatalytically Active TiO2 Films at 50°C

Australian Journal of Chemistry ◽

10.1071/ch11163 ◽

2011 ◽

Vol 64 (9) ◽

pp. 1235 ◽

Cited By ~ 2

Author(s):

Gregory K. L. Goh ◽

Kelvin Y. S. Chan ◽

Gao S. Huang ◽

Qui L. Tay

Keyword(s):

Thin Films ◽

Methylene Blue ◽

Liquid Phase ◽

Anatase Tio2 ◽

Blue Dye ◽

Tio2 Films ◽

Methylene Blue Dye ◽

Liquid Phase Deposition ◽

Grown Film ◽

Tio2 Thin Films

Epitaxial anatase TiO2 thin films were grown on (001) oriented SrTiO3 single crystal substrates by liquid phase deposition at 50°C. The film consisted of nanosized crystallites and exhibited a significant void fraction of 31 %. This contributed to the cracking of thicker films due to the generation of capillary stresses in the nanosized pores during drying. This porosity also comes in useful during the photodegradation of a methylene blue dye by an as-grown film.

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

International Journal of Photoenergy ◽

10.1155/2020/1627498 ◽

2020 ◽

Vol 2020 ◽

pp. 1-11 ◽

Cited By ~ 8

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%).

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Immobilization of a Series of Homo/Heterobinuclear Metal (II) Phthalocyanine Hexasulphonates on Nanocrystalline TiO2 Thin Films and their Application in the Degradation of Methylene Blue

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.356-360.1728 ◽

2011 ◽

Vol 356-360 ◽

pp. 1728-1732

Author(s):

Yan Zhen Yang ◽

Ren Jie Sun ◽

Yu Cheng Wu ◽

Li Tao ◽

Cheng Wu Shi

Keyword(s):

Thin Film ◽

Thin Films ◽

Methylene Blue ◽

Catalytic Activity ◽

Visible Light ◽

Visible Light Irradiation ◽

Light Irradiation ◽

Dark Condition ◽

Tio2 Thin Films ◽

Nanocrystalline Tio2

A series of binuclear metal (II) phthalocyanine hexasulphonates, (M-M)Pc, including (Co-Co)Pc, (Co-Zn)Pc, (Co-Mn)Pc, (Zn-Zn)Pc, (Zn-Mn)Pc and (Mn-Mn)Pc were synthesized and immobilized on nanocrystalline TiO2 thin films. The nanocrystalline TiO2 thin film was characterized by SEM, XRD and profilometer. The catalytic activity of various (M-M)Pc/nanocrystalline TiO2 thin films was evaluated by the degradation of methylene blue (MB) with air as the oxidant under visible light irradiation and dark condition. The results indicated that the prepared nanocrystalline TiO2 thin film had good crystalline and uniform particle size distribution. According to the degradation results of MB, various homo/hetero (M-M)Pc can sensitize nanocrystalline TiO2 thin films and improve their photocatalytic activity under visible light irradiation. The catalytic activity of hetero (M-M)Pc/nanocrystalline TiO2 thin films were more effective than that of homo (M-M)Pc under both visible light irradiation and dark condition, and the air purging was essential in degradation of MB. Therefore, these (M-M)Pc/nanocrystalline TiO2 thin films can be applied to the degradation of MB as a promising catalyzer.

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Photocatalytic activity of V-doped TiO2 thin films for the degradation of methylene blue and rhodamine B dye solutions

Journal of the Australian Ceramic Society ◽

10.1007/s41779-017-0068-0 ◽

2017 ◽

Vol 53 (2) ◽

pp. 569-576 ◽

Cited By ~ 18

Author(s):

W.-F. Chen ◽

P. Koshy ◽

L. Adler ◽

C. C. Sorrell

Keyword(s):

Thin Films ◽

Methylene Blue ◽

Photocatalytic Activity ◽

Rhodamine B ◽

Tio2 Thin Films ◽

Doped Tio2 ◽

Rhodamine B Dye ◽

Dye Solutions

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Comparative Study of ZnO Thin Films Doped with Transition Metals (Cu and Co) for Methylene Blue Photodegradation under Visible Irradiation

Catalysts ◽

10.3390/catal10050528 ◽

2020 ◽

Vol 10 (5) ◽

pp. 528 ◽

Cited By ~ 2

Author(s):

William Vallejo ◽

Alvaro Cantillo ◽

Briggitte Salazar ◽

Carlos Diaz-Uribe ◽

Wilkendry Ramos ◽

...

Keyword(s):

Thin Films ◽

Methylene Blue ◽

Sol Gel ◽

Physicochemical Characterization ◽

Thin Film Deposition ◽

Sem Analysis ◽

Film Deposition ◽

Morphological Properties ◽

Visible Irradiation ◽

Doped Zno

We synthesized and characterized both Co-doped ZnO (ZnO:Co) and Cu-doped ZnO (ZnO:Cu) thin films. The catalysts’ synthesis was carried out by the sol–gel method while the doctor blade technique was used for thin film deposition. The physicochemical characterization of the catalysts was carried out by Raman spectroscopy, scanning electron microscopy (SEM), X-ray diffraction, and diffuse reflectance measurements. The photocatalytic activity was studied under visible irradiation in aqueous solution, and kinetic parameters were determined by pseudo-first-order fitting. The Raman spectra results evinced the doping process and suggested the formation of heterojunctions for both dopants. The structural diffraction patterns indicated that the catalysts were polycrystalline and demonstrated the presence of a ZnO wurtzite crystalline phase. The SEM analysis showed that the morphological properties changed significantly, the micro-aggregates disappeared, and agglomeration was reduced after modification of ZnO. The ZnO optical bandgap (3.22 eV) reduced after the doping process, these being ZnO:Co (2.39 eV) and ZnO:Co (3.01 eV). Finally, the kinetic results of methylene blue photodegradation reached 62.6% for ZnO:Co thin films and 42.5% for ZnO:Cu thin films.

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