Comparison of Photocatalytic Activities of Commercial Titanium Dioxide Powders Immobilised on Glass Substrates

AbstractSemiconductor photocatalysis is an advanced oxidation technology reported to be effective for the degradation of a wide range of organic pollutants found in water. Titanium dioxide is the most suitable photocatalyst for water treatment as it is insoluble under normal pH conditions, is photoactive, photostable, readily available and inexpensive. In this work Millennium Chemicals PC500, PC105, PC100, PC50, PC10 and Evonik Degussa P25 powders were immobilised onto borosilicate glass, via dip-coating and spray coating, producing thick films ranging from 0.2 to 1.4 mg catalyst per square cm of glass substrate. The photocatalytic activity of the immobilised films was compared under back-face UVA irradiation in a stirred-tank reactor using formic acid and phenol as model pollutants. Based upon the rate constant derived from the removal of the parent compound, and using the optimum catalyst loading determined under the experimental conditions employed, the order of photocatalytic activity for the degradation of formic acid was found to be P25 > PC100 > PC50 > PC105 ≥ PC500 > PC10, while for phenol degradation the order was P25 > PC50 > PC105 > PC100 ≥ PC500 > PC10.

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Phenol Degradation on Glass Fibres with Immobilized Titanium Dioxide Particles

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19950788 ◽

1995 ◽

Vol 60 (5) ◽

pp. 788-794 ◽

Cited By ~ 17

Author(s):

Vlasta Brezová ◽

Alžbeta Blažková ◽

Mirko Brezňan ◽

Peter Kottáš ◽

Michal Čeppan

Keyword(s):

Titanium Dioxide ◽

Aqueous Solutions ◽

Phenol Degradation ◽

Experimental Conditions ◽

Glass Fibres

The photocatalytic mineralization of phenol in aqueous solutions under various experimental conditions was employed, to test the activity of the prepared immobilized fibreglass/TiO2 photocatalysts. The particles of titanium dioxide P25 were coated on the surface of commercial fibreglass fabric by dipping in ethanolic TiO2 suspensions and were fixed by firing 6 h at 500 °C.

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Phenol Removal by a Novel Non-Photo-Dependent Semiconductor Catalyst in a Pilot-Scaled Study: Effects of Initial Phenol Concentration, Light, and Catalyst Loading

Journal of Nanomaterials ◽

10.1155/2014/457485 ◽

2014 ◽

Vol 2014 ◽

pp. 1-8

Author(s):

Xiao Chen ◽

Yan Liang ◽

Xuefei Zhou ◽

Yanling Zhang

Keyword(s):

Titanium Dioxide ◽

Uv Radiation ◽

Phenol Degradation ◽

Phenol Concentration ◽

Catalyst Loading ◽

Phenol Removal ◽

Operational Parameters ◽

Initial Concentration ◽

Light Area ◽

Initial Phenol Concentration

A novel non-photo-dependent semiconductor catalyst (CT) was employed to degrade phenol in the present pilot-scaled study. Effect of operational parameters such as phenol initial concentration, light area, and catalyst loading on phenol degradation, was compared between CT catalyst and the conventional photocatalyst titanium dioxide. CT catalyst excelled titanium dioxide in treating and mineralizing low-level phenol, under both mild UV radiation and thunder conditions of nonphoton. The result suggested that CT catalyst could be applied in circumstances when light is not easily accessible in pollutant-carrying media (e.g., particles, cloudy water, and colored water).

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Synthesis of Titanium Containing SBA-15 and Its Application for Photocatalytic Degradation of Phenol

International Journal of Chemical Engineering ◽

10.1155/2014/691562 ◽

2014 ◽

Vol 2014 ◽

pp. 1-7 ◽

Cited By ~ 4

Author(s):

Lili Yang ◽

Zeyu Jiang ◽

Sufeng Lai ◽

Chongwen Jiang ◽

Hong Zhong

Keyword(s):

Waste Water ◽

Titanium Dioxide ◽

Photocatalytic Activity ◽

Physicochemical Properties ◽

Phenol Degradation ◽

Titanium Content ◽

Structure Change ◽

Cyclic Performance ◽

One Pot ◽

Simulated Waste

We synthesized Ti-containing SBA-15 by one-pot hydrothermal method and extensively investigated its physicochemical properties and examined its photocatalytic activity to degrade phenol. It’s shown that appropriate amount of titanium could be effectively incorporated into the framework of SBA-15 without provoking structure change and the tetrahedrally coordinated titanium species were well-ordered in Ti-incorporated SBA-15. Under UV-irradiation, the Ti-containing SBA-15 exhibits good photocatalytic activity for phenol degradation in the simulated waste water. The higher photocatalytic activity of Ti-containing SBA-15 to degrade phenol was ascribed to the more titanium content and anatase titanium dioxide. In addition, the new photocatalyst displays a good regeneration and cyclic performance after six runs.

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Photoelectrocatalytic Degradation of Organic Pollutants in Aqueous Solution Using a Pt-TiO2Film

International Journal of Photoenergy ◽

10.1155/2009/634369 ◽

2009 ◽

Vol 2009 ◽

pp. 1-7 ◽

Cited By ~ 5

Author(s):

Chun He ◽

Mudar Abou Asi ◽

Ya Xiong ◽

Dong Shu ◽

Xiangzhong Li

Keyword(s):

Aqueous Solution ◽

Photocatalytic Activity ◽

Formic Acid ◽

Dip Coating ◽

Photoelectrochemical Properties ◽

X Ray Diffraction ◽

X Ray ◽

Photoelectrocatalytic Degradation ◽

Interfacial Charge ◽

Electronic Microscope

A series of Pt-TiO2films with nanocrystaline structure was prepared by a procedure of photodeposition and subsequent dip-coating. The Pt-TiO2films were characterized by X-ray diffraction, scanning electronic microscope, electrochemical characterization to examine the surface structure, chemical composition, and the photoelectrochemical properties. The photocatalytic activity of the Pt-TiO2films was evaluated in the photocatalytic (PC) and photoelectrocatalytic (PEC) degradation of formic acid in aqueous solution. Compared with aTiO2film, the efficiency of formic acid degradation using the Pt-TiO2films was significantly higher in both the PC and PEC processes. The enhancement is attributed to the action of Pt deposits on theTiO2surface, which play a key role by attracting conduction band photoelectrons. In the PEC process, the anodic bias externally applied on the illuminated Pt-TiO2films can further drive away the accumulated photoelectrons from the metal deposits and promote a process of interfacial charge transfer.

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Activity Enhancement of P25 Titanium Dioxide by Zinc Oxide for Photocatalytic Phenol Degradation

BULLETIN OF CHEMICAL REACTION ENGINEERING AND CATALYSIS ◽

10.9767/bcrec.16.2.10319.310-319 ◽

2021 ◽

Vol 16 (2) ◽

pp. 310-319

Author(s):

Yehezkiel Steven Kurniawan ◽

Leny Yuliati

Keyword(s):

Zinc Oxide ◽

Titanium Dioxide ◽

Photocatalytic Activity ◽

Rate Constant ◽

Phenol Degradation ◽

Reaction Rate Constant ◽

X Ray Diffraction ◽

Physical Mixing ◽

Mixing Method ◽

Activity Enhancement

As a benchmark photocatalyst, P25 titanium dioxide (TiO2) nanomaterial has been widely reported for its remarkable photocatalytic activity under ultraviolet (UV) irradiation. However, approaches to further improve the photocatalytic activity of the P25 TiO2 are still required. In the present work, we reported the activity enhancement of the P25 TiO2 up to more than five times higher rate constant for phenol degradation when the P25 TiO2 was coupled with zinc oxide (ZnO). The composites were prepared by a physical mixing method of P25 TiO2 and ZnO with various weight ratios of 1:0.5, 1:1, and 1:2. The composite materials were then characterized using X-ray diffraction (XRD), diffuse-reflectance ultraviolet-visible (DR UV-vis), Fourier transform infrared (FTIR), and fluorescence spectroscopies. All the composites gave better activity than the P25 TiO2, in which the TiO2/ZnO 1:1 composite material exhibited the highest first-order reaction rate constant (0.43 h−1). This remarkable enhanced degradation rate was much higher than that of the unmodified TiO2 (0.08 h−1) and ZnO (0.13 h-1). The fluorescence study revealed that the electron-hole recombination on the P25 TiO2 could be suppressed by the ZnO, which would be the reason for such activity enhancement. A study on the effect of the scavenger showed that the hydroxyl radicals played a crucial role in the photocatalytic phenol degradation. Copyright © 2021 by Authors, Published by BCREC Group. This is an open access article under the CC BY-SA License (https://creativecommons.org/licenses/by-sa/4.0).

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Synthesis and Photocatalytic Activity of TiO2 on Phenol Degradation

Kuwait Journal of Science ◽

10.48129/kjs.13509 ◽

2021 ◽

Author(s):

Muhamad D. Permana ◽

◽

Atiek R. Noviyanti ◽

Putri R. Lestari ◽

Nobuhiro Kumada ◽

...

Keyword(s):

Titanium Dioxide ◽

Photocatalytic Activity ◽

Band Gap ◽

Crystallite Size ◽

Titanium Dioxide Nanoparticles ◽

Sol Gel ◽

Phenol Degradation ◽

High Catalytic Activity ◽

Titanium Tetraisopropoxide ◽

Titanium Butoxide

Photocatalysis is a process of accelerating reactions that are assisted by energy from light irradiation. Titanium dioxide (TiO2) is one of the most widely developed photocatalysis materials, and is used because of its high catalytic activity, stability and very affordable. The most commonly used precursors of TiO2 are titanium butoxide (TBOT) and titanium tetraisopropoxide (TTIP). These variations in precursor can lead to phase difference in the formation of TiO2 crystals, which further improves its nature in the activity of photocatalysis. In this study, the sol-gel method was used to synthesize titanium dioxide nanoparticles from variations of TBOT and TTIP. Furthermore, the structure, crystallite size and band gap of TiO2 were determined by X-ray diffraction (XRD) and UV-vis reflectance spectroscopy (DRS). Subsequently, TiO2 photocatalytic activity was evaluated in phenol photodegradation as a contaminant model with UV irradiation. The results showed the structure synthesized from TBOT had a higher amount of anatase, higher crystallinity, smaller crystallite size, larger band gap, and better photocatalytic activity than those from TTIP. Furthermore, it was shown that TiO2 from TBOT had an efficiency of 147% greater than TiO2 P25 Degussa, while TiO2 from TTIP had 66% efficiency compared to TiO2 P25.

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The degradation of phenol in water solution by TiO2 photocatalysis in a helical reactor

Global NEST Journal ◽

10.30955/gnj.000525 ◽

2013 ◽

Vol 10 (3) ◽

pp. 404-418 ◽

Cited By ~ 1

Keyword(s):

Titanium Dioxide ◽

Light Intensity ◽

Uv Irradiation ◽

Photocatalytic Oxidation ◽

Irradiation Time ◽

Water Solution ◽

Phenol Degradation ◽

Flow Mode ◽

Order Kinetic ◽

Wide Range

Heterogeneous photocatalysis is an advanced oxidation process (AOP) which has been widely studied by numerous researchers in the world and is used to degrade or remove a wide range of pollutants in water and air. The photocatalytic oxidation and mineralization of phenol in aqueous catalyst suspensions of titanium dioxide (TiO2) Degussa P25 (80% anatase, 20% rutile) has been carried out in a helical reactor. The photodegradation was investigated using two kinds of high pressure mercury irradiation lamps one emitting at 254 nm (15 Watts) and the other emitting at 365 nm (400 Watts). The effects of the recirculation flow, source of withdrawal, initial phenol concentration, amount of catalyst, suspension pH and light intensity on photodegradation of phenol were investigated. These parameters were studied to find the optimal conditions for a complete and fast oxidation of this organic compound. Kinetic experiments were performed at 32 oC over a range of phenol concentrations from 2.5 to 25 mg l-1, a range of TiO2 concentrations from 0.1 to 1 g l1, a range of suspensions pH from 3 to 9. The helical reactor was operated under a continuous flow-mode. Results showed that photodegradation is an effective method for the removal of phenol from wastewaters. The efficiency of the process depends strongly on the experimental conditions. The amount of catalyst, UV irradiation time, pH and light intensity were important parameters in the degradation process. The rate constants for the different parameters (TiO2, phenol concentration) were evaluated. Kinetic studies showed that titanium dioxide photocatalyst P25 was very active in phenol degradation; we observed that 99% of pollutant was degraded after 6 hours of UV irradiation; furthermore, we observed that phenol degradation was more effective under acidic conditions than alkaline. The kinetics were described by the Langmuir- Hinshelwood (L-H) kinetic model. An overall pseudo-first order kinetic constant has been calculated for phenol conversion and values obtained in acidic pH are higher than those calculated for basic pH media.

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Protective films of stearic and octadecylphosphonic acid formed by spray coating

Journal of Electrochemical Science and Engineering ◽

10.5599/jese.739 ◽

2020 ◽

Vol 10 (2) ◽

pp. 161-175

Author(s):

Ekatarina Kristan Mioč ◽

Helena Otmačić Ćurković

Keyword(s):

Corrosion Behaviour ◽

Spray Coating ◽

Dip Coating ◽

Experimental Conditions ◽

Film Stability ◽

Protective Properties ◽

Coating Method ◽

Spectroscopy Studies ◽

Dip Coating Method ◽

Octadecylphosphonic Acid

Spray coating formation of stearic and octadecylphosphonic acid films for corrosion protection of cupronickel alloy was studied in this work as a more practical alternative to widely studied dip-coating method. Protective properties of organic films formed under various experimental conditions were examined by electrochemical studies in 3% NaCl solution as a corrosive medium. Polarization resistance measurements as well as electrochemical impedance spectroscopy were employed to follow in time the corrosion behaviour of cupronickel alloy modified by studied organic acids. It was found that among examined experimental parameters, time elapsed between two sprays and number of sprays have the strongest influence on the film stability and its protective properties. This study confirmed that it is possible to form by spray coating the films of stearic and octadecylphosphonic acid with protective properties that resemble to those of the films prepared by dip-coating method. Differences in corrosion behaviour of samples protected with stearic and octadecylphosphonic acid were attributed to difference in the bond strength between substrate and each organic acid. Studied samples were also examined by the scanning electron microscopy. Fourier transformed infrared spectroscopy studies showed that crystalline structure dominates in studied films, while contact angle measurements confirmed that modified cupronickel alloy surface exhibits hydrophobic properties.

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Crystal Engineering of Bi2WO6 to Polar Aurivillius-Phase Oxyhalides

10.26434/chemrxiv.9741701.v1 ◽

2019 ◽

Author(s):

Kazuki Morita ◽

Ji-Sang Park ◽

Sunghyun Kim ◽

Kenji Yasuoka ◽

Aron Walsh

Keyword(s):

Photocatalytic Activity ◽

Crystal Engineering ◽

First Principles ◽

Parent Compound ◽

Aurivillius Phase ◽

Aurivillius Phases ◽

Charge Neutrality ◽

Bismuth Oxides ◽

Structure Surface ◽

Electric Dipoles

The Aurivillius phases of complex bismuth oxides have attracted considerable attention due to their lattice polarization (ferroelectricity) and photocatalytic activity. We report a first-principles exploration of Bi2WO6 and the replacement of W6+ by pentavalent (Nb5+, Ta5+) and tetravalent (Ti4+, Sn4+) ions, with charge neutrality maintained by the formation of a mixed-anion oxyhalide sublattice. We find that Bi2SnO4F2 is thermodynamically unstable, in contrast to Bi2TaO5F, Bi2NbO5F and Bi2TiO4F2. The electric dipoles introduced by chemical substitutions in the parent compound are found to suppress the spontaneous polarization from 61.55 μC/cm2 to below 15.50 μC/cm2. Analysis of the trends in electronic structure, surface structure, and ionization potentials are reported. This family of materials can be further extended with control of layer thicknesses and choice of compensating halide species.

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Strongly Coupled Redox-Linked Conformational Switching at the Active Site of the Non-Heme Iron-Dependent Dioxygenase, TauD

10.26434/chemrxiv.9461462 ◽

2019 ◽

Author(s):

Christopher John ◽

Greg M. Swain ◽

Robert P. Hausinger ◽

Denis A. Proshlyakov

Keyword(s):

Active Site ◽

Structural Model ◽

Heme Iron ◽

Chemical Transformations ◽

Experimental Conditions ◽

Strongly Coupled ◽

Non Heme Iron ◽

Reversible Redox ◽

Wide Range ◽

Complex Structural

2-Oxoglutarate (2OG)-dependent dioxygenases catalyze C-H activation while performing a wide range of chemical transformations. In contrast to their heme analogues, non-heme iron centers afford greater structural flexibility with important implications for their diverse catalytic mechanisms. We characterize an in situ structural model of the putative transient ferric intermediate of 2OG:taurine dioxygenase (TauD) by using a combination of spectroelectrochemical and semi-empirical computational methods, demonstrating that the Fe (III/II) transition involves a substantial, fully reversible, redox-linked conformational change at the active site. This rearrangement alters the apparent redox potential of the active site between -127 mV for reduction of the ferric state and 171 mV for oxidation of the ferrous state of the 2OG-Fe-TauD complex. Structural perturbations exhibit limited sensitivity to mediator concentrations and potential pulse duration. Similar changes were observed in the Fe-TauD and taurine-2OG-Fe-TauD complexes, thus attributing the reorganization to the protein moiety rather than the cosubstrates. Redox difference infrared spectra indicate a reorganization of the protein backbone in addition to the involvement of carboxylate and histidine ligands. Quantitative modeling of the transient redox response using two alternative reaction schemes across a variety of experimental conditions strongly supports the proposal for intrinsic protein reorganization as the origin of the experimental observations.

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