Studies on photocatalytic activity of the synthesised TiO2 and Ag/TiO2 photocatalysts under UV and sunlight irradiations

2011 ◽  
Vol 63 (3) ◽  
pp. 377-384 ◽  
Author(s):  
R. Vaithiyanathan ◽  
T. Sivakumar
Keyword(s):  
Uv Light ◽  
Sol Gel ◽  
Solar Light ◽  
Light Sources ◽  
Tio2 Photocatalysts ◽  
First Order ◽  
First Order Kinetics ◽  
Radiation Sources ◽  
Silver Metal ◽  
Comprehensive Study

Photocatalytic decolorisation and degradation of Reactive Red 120 (RR 120) has been investigated under UV (365 nm) and solar light as radiation sources using synthesised nano titania catalyst prepared via sol-gel method. The study encompassed calcination of synthesised titania catalyst at a range of temperature up to 1,000°C. The effects of calcination temperature on titania catalyst have been evaluated on the decolorisation of RR 120. The analysis revealed complete decolorisation of dye solution in 100 min under UV light with the TiO2 catalyst calcined at 200°C. Only a maximum of 47% dye decolorisation was achieved under sunlight in 4 h with no improvement even after prolonged irradiation. In an endeavour to improve the catalytic activity, bare titania was modified with silver metal and a comprehensive study on the characteristics of silver modified catalyst was made. The result was an enhancement of the rate of decolorisation of dye under both UV and solar light sources. All the catalysts were characterised by XRD and BET analyses. Optimisation of the degradation of RR 120 has been carried out using the unmodified catalyst by varying the amount of catalyst, substrate concentration, pH of dye solution. Effects of addition of small amounts of various oxidants such as H2O2, KBrO3 and (NH4)2S2O8 have also been studied. Pseudo first order kinetics was observed in the photocatalytic decolorisation of dye. The mineralisation of RR 120 was monitored by TOC analysis.

Disinfection effects on E. coli using TiO2/UV and solar light system

2002 ◽  
Vol 2 (1) ◽  
pp. 181-190 ◽  
Author(s):  
I.-H. Cho ◽  
I.-Y. Moon ◽  
M.-H. Chung ◽  
H.-K. Lee ◽  
K.-D. Zoh
Keyword(s):  
Light Intensity ◽  
Flow Rate ◽  
Alternative Energy ◽  
Advanced Oxidation Process ◽  
Uv Light ◽  
Solar Light ◽  
Survival Ratio ◽  
E Coli ◽  
First Order ◽  
First Order Kinetics

First, a continuous flow TiO2/UV reactor was designed and developed in order to examine E. coli disinfection effect using UV light. The optimum conditions for disinfection such as flow rate, light intensity, TiO2 concentration, initial E. coli concentration were examined. The results are as follow (i) The use of the quartz device and TiO2 (anatase) resulted in killing of E. coil within minutes. (ii) Photocatalytic disinfection with UV light in the presence of TiO2 more effectively killed E. coli than UV or TiO2 adsorption only. (iii) As flow rate increased, the survival ratio of E. coli decreased, but over 3 L/min of flow rate, the efficiency was limited. (iv) E. coli survival ratio decreased linearly with increasing UV light intensity. (v) The dosage of TiO2 affected the E. coli disinfection efficiency, and above 0.1 wt% TiO2 concentration, the disinfection was less effective because TiO2 particles may result in screening off the light. (ri) The disinfection reaction follows first-order kinetics. Secondly, outdoor experiments with natural sunlight instead of artificial UV light in TiO2 reactors were also conducted to investigate alternative energy source applicability on E. coli disinfection. It is found that the presence of clouds in the sky markedly increased the time required for killing E. coli and the bacteria cells also disappeared with a first-order kinetics. On the basis of these experimental observations, the disinfection of E. coli using TiO2 under solar light irradiation can be a feasible application of the advanced oxidation process.

Photocatalytic Discolouration of Solutions of Reactive Dyes in the Presence of H2O2

1995 ◽  
Vol 30 (1) ◽  
pp. 53-60 ◽  
Author(s):  
Deng Nansheng ◽  
Tian Shizhong ◽  
Xia Mei
Keyword(s):  
Photochemical Reaction ◽  
Uv Light ◽  
Reactive Dyes ◽  
Solar Light ◽  
Rate Equations ◽  
Oh Radical ◽  
Test Results ◽  
Dye Molecules ◽  
First Order ◽  
Dye Solutions

Abstract Tests for the photocatalytic degradation of solutions of three reactive dyes, Red M-5B, Procion Blue MX-R and Procion Black H-N, in the presence of H2O2 were carried out. When the solutions of the three reactive dyes were irradiated by UV or solar light, the colour of the solutions disappeared gradually. A statistical analysis of the test results indicated a linear relation between the concentration of dyes and the time of irradiation. The discolouration reaction of the solutions was of the first order. Rate equations for the discolouration reactions of dye solutions were developed. The dark reactions or the dye solutions containing H2O2 were very slow, illustrating that the photochemical reaction played a very important role. It was demonstrated that UV light and solar light (300 to 380 nm) photolyzes the HO and that the resulting OH radical reacts with the dye molecules and destroys the chromophore.

Photocatalytic Efficiency for Dye Decolorization of the UV/TiO2, UV/TiO2 + In2O3 and UV/TiO2-In2O3 Systems

2013 ◽  
Vol 831 ◽  
pp. 263-266
Author(s):  
Chung Hsin Wu ◽  
Chao Yin Kuo ◽  
Chih Hao Lai ◽  
Wei Yang Chung
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
Dye Decolorization ◽  
X Ray Diffraction ◽  
First Order ◽  
First Order Kinetics ◽  
Vis Spectroscopy ◽  
Reactive Red 2

This study explored the decolorization of C.I. Reactive Red 2 (RR2) by the ultraviolet (UV)/TiO2, UV/TiO2 + In2O3, and UV/TiO2-In2O3 systems. The TiO2-In2O3 was generated by the sol-gel method and TiO2 + In2O3 was created by mixing TiO2 and In2O3 powders. The surface properties of TiO2, In2O3, and TiO2-In2O3 were analyzed by X-ray diffraction, a specific surface area analyzer, UV-vis spectroscopy, and scanning electron microscopy. The specific surface area of TiO2, In2O3, and TiO2-In2O3 was 29.5, 44.6, and 35.7 m2/g, respectively; additionally, the band gap of TiO2, In2O3, and TiO2-In2O3 was 2.95, 2.64, and 2.91 eV; respectively. The decolorization rate constant fit pseudo-first-order kinetics and that of the UV/TiO2, UV/TiO2 + In2O3, and UV/TiO2-In2O3 systems was 0.0023, 0.0031, and 0.0072 min-1; respectively.

scholarly journals Estudios fotoquímicos y electroquímicos de complejos lantánidos de 6-(hidroximetil)piridin- 2-carboxaldehído[2- metilpirimidina-4,6-diil] bishidrazona

2015 ◽  
Vol 43 (1) ◽  
pp. 5-11 ◽  
Author(s):  
María Alejandra Fernandez ◽  
Juan Camilo Barona ◽  
Dorian Polo-Cerón ◽  
Manuel N. Chaur
Keyword(s):  
Uv Light ◽  
Condensation Reaction ◽  
Quantum Yields ◽  
Consecutive Reaction ◽  
Metal Centers ◽  
First Order ◽  
Fluorescence Quantum Yields ◽  
H Nmr ◽  
First Order Kinetics ◽  
Uv Light Irradiation

<p>Herein we report the synthesis of the 6-(hydroxymethyl)pyridine-2- carboxaldehyde[2-methyl-pyrimidine- 4,6-diyl]bis-hydrazone by a condensation reaction between 6-(hydroxymethyl) picolinaldehyde with 4,6-(bis-hydrazino)-2- methylpyrimidine. This bis-hydrazone can be visualized as a two-arm system which exhibits photochemical induced [E,E]/[E,Z]/[Z,Z’] isomerizations and double coordination to metal centers. Configurational changes, upon UV light irradiation, were followed over time by 1 H NMR, establishing that isomerization, in both arms, is a consecutive reaction that follows first-order kinetics (k1 = 4.06 x 10-4 s-1 and k2 = 2.80 x 10-4 s-1). Furthermore, the synthesis of bis-hydrazone metal complexes with La (III) and Sm (III) ions was achieved; subsequently, the absorption and emission properties of these complexes were studied, determining the fluorescence quantum yields, 𝟇La= 0.2024 and 𝟇Sm= 0.1413. Electrochemical studies of the complexes were conducted by square wave voltammetry, demonstrating that the bis-hydrazone and its complexes are electroactive species between +1.5 and -2.5 V.</p>

scholarly journals Photodegradation of lincomycin in aqueous solution

2006 ◽  
Vol 2006 ◽  
pp. 1-6 ◽  
Author(s):  
Agatino Di Paola ◽  
Maurizio Addamo ◽  
Vincenzo Augugliaro ◽  
Elisa García-López ◽  
Vittorio Loddo ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Aqueous Solutions ◽  
Uv Light ◽  
Heterogeneous Systems ◽  
Degradation Pathways ◽  
Direct Photolysis ◽  
First Order ◽  
First Order Kinetics ◽  
Pseudo First Order ◽  
Complete Mineralization

Aqueous solutions of lincomycin were irradiated with UV light in homogeneous and heterogeneous systems. Lincomycin disappeared in both systems but the presence ofTiO2noticeably accelerated the degradation of the antibiotic in comparison with direct photolysis. The rate of decomposition was dependent on the concentration of lincomycin and followed a pseudo-first-order kinetics. Photolysis involved only the oxidation of lincomycin without mineralization. Differently, the treatment withTiO2and UV light resulted in a complete mineralization of the antibiotic. The degradation pathways involved S- and N-demethylation and propyldealkylation. The mineralization of the molecule led to the formation of sulfate, ammonium, and nitrate ions.

Decolourization of Methylene Blue by Persulfate

2013 ◽  
Vol 634-638 ◽  
pp. 76-80
Author(s):  
Wei Hu ◽  
Shen Xin Li ◽  
Cheng Duan Wang
Keyword(s):  
Methylene Blue ◽  
Ionic Strength ◽  
Uv Irradiation ◽  
Reaction Temperature ◽  
Uv Light ◽  
Kinetics Model ◽  
Dye Wastewater ◽  
First Order ◽  
First Order Kinetics ◽  
Pseudo First Order

The decolourization of dye wastewater by persulfate was studied using methylene blue as a model dye wastewater. Effects of several parameters, such as dose of oxidant, ionic strength, pH, temperature and UV irradiation, were investigated in detail. The results showed that the decolourization reaction of methylene blue by persulfate could be fitted to a pseudo-first order kinetics model. In addition, when the oxidant amount used is 2 times of methylene blue, pH 3.43 and reaction temperature for 60°C, after uv light under the irradiation of 20 min, methylene blue decolorization rate can reach more than 98%. The results are useful for the treatment of dye wastewater.

Photocatalytic Degradation of Reactive Brilliant Blue KN-R by N, Fe- TiO2/FFA

2011 ◽  
Vol 183-185 ◽  
pp. 2028-2031
Author(s):  
Gui Rong Wang
Keyword(s):  
Ph Value ◽  
Sol Gel ◽  
Dip Coating ◽  
Brilliant Blue ◽  
X Ray Diffraction ◽  
X Ray ◽  
First Order ◽  
Operation Conditions ◽  
First Order Kinetics ◽  
Fe Ions

TiO2 photocatalyst modified by N and Fe ions was loaded on self-made fly ash forming adsorbent (FFA) using the sol-gel dip-coating process. The crystal structure and photoadsorption ability was characterized by X-ray diffraction (XRD) and UV-Vis spectrophotometer, respectively. The photo catalytic degradation of Reactive Brilliant Blue KN-R using N, Fe-TiO2/FFA was examined. Effects of initial dye concentration, pH value and hydrogen peroxide dosage on degradation were studied. The degradation of the organic molecule followed a pseudo-first-order kinetics according to the Langmuir model. Under the optimum operation conditions, 30 mg/L KN-R could be decolorized over 97.47% within 75 min.

Photodegradation of organic matter in fresh garbage leachate using immobilized nano-sized TiO2 as catalysts

2013 ◽  
Vol 69 (6) ◽  
pp. 1219-1226
Author(s):  
C. Chen ◽  
Q. Xie ◽  
B. Q. Hu ◽  
X. L. Zhao
Keyword(s):  
Organic Matter ◽  
Activated Carbon ◽  
Degradation Rate ◽  
Sol Gel ◽  
Oxygen Demand ◽  
Solution Ph ◽  
First Order ◽  
First Order Kinetics ◽  
Catalyst Dosage ◽  
H2o2 Addition

Two immobilized nano-sized TiO2 catalysts, TiO2/activated carbon (TiO2/AC) and TiO2/silica gel (SG) (TiO2/SG), were prepared by the sol–gel method, and their use in the photocatalytic degradation of organic matter in fresh garbage leachate under UV irradiation was investigated. The influences of the catalyst dosage, the initial solution pH, H2O2 addition and the reuse of the catalysts were evaluated. The degradation of organic matter was assessed based on the decrease of the chemical oxygen demand (COD) in the leachate. The results indicated that the degradation of the COD obeyed first-order kinetics in the presence of both photocatalysts. The degradation rate of COD was found to increase with increasing catalyst dosage up to 9 g/L for TiO2/AC and 6 g/L for TiO2/SG, above which the degradation began to attenuate. Furthermore, the degradation rate first increased and then decreased as the solution pH increased from 2 to 14, and the degradation rate increased as the amount of H2O2 increased to 2.93 mM, after which it remained constant. No obvious decrease in the rate of COD degradation was observed during the first four repeated uses of the photocatalysts, indicating that the catalysts could be recovered and reused. Compared with TiO2/AC, TiO2/SG exhibited higher efficiency in photocatalyzing the degradation of COD in garbage leachate.

scholarly journals Photocatalytic Degradation of 2-Chlorophenol Using Ag-Doped TiO2Nanofibers and a Near-UV Light-Emitting Diode System

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Ju-Young Park ◽  
In-Hwa Lee
Keyword(s):  
Phase Transformation ◽  
Photocatalytic Degradation ◽  
Uv Light ◽  
Light Emitting Diode ◽  
Sol Gel ◽  
Order Equation ◽  
Light Emitting ◽  
First Order ◽  
Uv Led ◽  
Diode System

This report investigated the photocatalytic degradation of 2-chlorophenol using TiO2nanofibers and Ag-doped TiO2nanofibers, synthesized using the sol-gel and electrospinning techniques, and an ultraviolet light-emitting diode (UV-LED) system as a UV light source. The crystallite size of the Ag-doped TiO2nanofibers was smaller than that of the TiO2nanofibers, because silver retrained phase transformation not only controls the phase transformation but also inhibits the growth of anatase crystallites. The activation energies for the grain growth of the TiO2nanofibers and the Ag-doped TiO2nanofibers were estimated to be 20.84 and 27.01 kJ/mol, respectively. The photocatalytic degradation rate followed a pseudo-first-order equation. The rate constants (k) of the TiO2nanofibers and the Ag-doped TiO2nanofibers were 0.056 and 0.144 min−1, respectively.

scholarly journals A light-driven supramolecular nanowire actuator

Nanoscale ◽  
2015 ◽  
Vol 7 (15) ◽  
pp. 6457-6461 ◽  
Author(s):  
Junho Lee ◽  
Seungwhan Oh ◽  
Jaeyeon Pyo ◽  
Jong-Man Kim ◽  
Jung Ho Je
Keyword(s):  
Visible Light ◽  
Visible Light Irradiation ◽  
Uv Light ◽  
Light Irradiation ◽  
First Order ◽  
First Order Kinetics ◽  
Bending Behavior

Single light-driven molecular nanowire actuator is first developed that employs the azobenzene-containing tris(4-((E)-phenyldiazenyl)phenyl)-benzene-1,3,5-tricarboxamide (Azo-1). Single Azo-1 nanowires undergo bending upon irradiation with UV light that is reversed upon visible light irradiation, and the bending behavior follows first-order kinetics associated with azobenzene photoisomerization.

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