Semiconductor Mediated Photocatalysed Reaction of Two Selected Organic Compounds in Aqueous Suspensions of Titanium Dioxide

2012 ◽  
Vol 15 (2) ◽  
Author(s):  
Niyaz A. Mir ◽  
M.M. Haque ◽  
A. Khan ◽  
K. Umar ◽  
M. Muneer ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Organic Carbon ◽  
Photocatalytic Degradation ◽  
Organic Compounds ◽  
Substrate Concentration ◽  
Degradation Kinetics ◽  
Irradiation Time ◽  
Aqueous Suspensions ◽  
Kinetics Of

AbstractSemiconductor mediated hydrogen peroxide-assisted photocatalytic degradation of two selected pesticide compounds, chloramben (1) and cyanazine (2) has been investigated in aqueous suspensions under a variety of conditions. The degradation was studied by monitoring the depletion in total organic carbon (TOC) content and decrease in substrate concentration as a function of irradiation time. The degradation kinetics of pesticide compounds 1 and 2 were investigated under different conditions such as type of TiO

Semiconductor-Mediated Photocatalysed Degradation of Various Pesticide Derivatives and Other Priority Organic Pollutants in Aqueous Suspensions

2005 ◽  
Vol 486-487 ◽  
pp. 61-64
Author(s):  
Detlef W. Bahnemann ◽  
M. Muneer ◽  
M. Qamar ◽  
M.A. Rahman ◽  
H.K. Singh
Keyword(s):  
Titanium Dioxide ◽  
Organic Carbon ◽  
Organic Pollutants ◽  
Spectroscopic Analysis ◽  
Vibrio Fischeri ◽  
Degradation Kinetics ◽  
Irradiation Time ◽  
Aqueous Suspensions ◽  
Degradation Rates ◽  
Hplc Technique

The photocatalysed degradation of various selected pesticide derivatives, namely N,NDimethyl- a-phenyl benzene acetamide (Diphenamid) [1], 1,2-diethyl phthalate (DEP) [2], 5-bromo- 3-sec.butyl-6-methyl uracil (Bromacil) [3], 3-tert-butyl-5-chloro-6-methyluracil (Terbacil), 2,4,5- tribromoimidazole (TBI) [4], Methoxychlor, Chlorothalonil and Disulfoton [5] as well as that of two selected priority organic pollutants, namely benzidine and 1,2-diphenyhydrazine (DPH) [6], has been investigated in aqueous suspensions of titanium dioxide (TiO2) under a variety of conditions. The degradation was studied by monitoring the change in substrate concentration employing UV spectroscopic analysis or HPLC technique and the decrease in total organic carbon (TOC) content, respectively, as a function of irradiation time. The degradation kinetics was studied under different conditions such as reaction pH, substrate and photocatalyst concentration, type of photocatalysts and the presence of alternative additives such as H2O2, KBrO3 and (NH4)2S2O8 besides molecular oxygen. The degradation rates and the photonic efficiencies were found to be strongly influenced by the above parameters. A toxicity test was performed for irradiated samples of few selected systems measuring the luminescence of bacteria Vibrio fischeri after 30 minutes of incubation.

Titanium Dioxide-mediated Photocatalysed Mineralization of Two Selected Organic Pollutants in Aqueous Suspensions

2013 ◽  
Vol 16 (2) ◽  
Author(s):  
Khalid Umar ◽  
M. M. Haque ◽  
Niyaz A. Mir ◽  
M. Muneer ◽  
I. H. Farooqi
Keyword(s):  
Titanium Dioxide ◽  
Organic Pollutants ◽  
Hplc Analysis ◽  
Irradiation Time ◽  
Atmospheric Oxygen ◽  
Model Compounds ◽  
Aqueous Suspensions ◽  
Analysis Technique ◽  
Mineralization Kinetics ◽  
Kinetics Of

AbstractTitanium dioxide-mediated photocatalytic mineralization of two selected organic pollutants such as Metalaxyl (ML) and Tinidazole (TN) has been investigated in aqueous suspensions in the presence of atmospheric oxygen under a variety of conditions. The mineralization was studied by monitoring the depletion in total organic carbon (TOC) content as a function of irradiation time. In addition HPLC analysis technique was also used to monitor the degradation of model compounds under investigations. The mineralization kinetics of both compounds were investigated under different conditions such as type of TiO

Photocatalytic degradation kinetics of methyl orange in TiO2–SiO2–NiFe2O4 aqueous suspensions

2012 ◽  
Vol 39 (4) ◽  
pp. 1673-1684 ◽  
Author(s):  
Lijun Yan ◽  
Yue Cheng ◽  
Shuai Yuan ◽  
Xiaojuan Yan ◽  
Xuefeng Hu ◽  
...  
Keyword(s):  
Methyl Orange ◽  
Photocatalytic Degradation ◽  
Degradation Kinetics ◽  
Aqueous Suspensions ◽  
Kinetics Of

Photocatalytic degradation kinetics of humic acid in aqueous TiO2 dispersions: the influence of hydrogen peroxide and bicarbonate ion

1996 ◽  
Vol 34 (9) ◽  
pp. 73-80 ◽  
Author(s):  
Miray Bekbölet ◽  
Isil Balcioglu
Keyword(s):  
Hydrogen Peroxide ◽  
Humic Acid ◽  
Photocatalytic Degradation ◽  
Rate Constants ◽  
Degradation Rate ◽  
Ph Value ◽  
Degradation Kinetics ◽  
Color Removal ◽  
Degradation Data ◽  
Kinetics Of

The degradation of humic acid in water by means of photocatalytic method has been studied. The influence of hydrogen peroxide and bicarbonate has also been investigated. The kinetics of the photocatalytic degradation of humic acid in various concentrations (50-500 mg/L) has been followed by the determination of TOC, COD and UV-vis spectra of the reaction solution. While the pseudo first order rate constants of 50 mg/L humic acid were found 0.016, 0.03 and 0.036 for TOC, Color400 and UV254, the degradation rate constants for these parameters were found 0.029, 0.069 and 0.057 in the presence of 1×10−2M H2O2. The Langmuir-Hinshelwood kinetic has also been sucessfully applied to the photocatalytic degradation data. It was found that bicarbonate ions slowed down the degradation rate by scavenging the hydroxyl radicals. Low pH value has been found to be favorable for color removal in the absence of hydrogen peroxide whereas natural pH gave the best results for color removal in the presence of hydrogen peroxide.

scholarly journals Influence of Irradiance, Flow Rate, Reactor Geometry, and Photopromoter Concentration in Mineralization Kinetics of Methane in Air and in Aqueous Solutions by Photocatalytic Membranes Immobilizing Titanium Dioxide

2008 ◽  
Vol 2008 ◽  
pp. 1-14 ◽  
Author(s):  
Ignazio Renato Bellobono ◽  
Mauro Rossi ◽  
Andrea Testino ◽  
Franca Morazzoni ◽  
Riccardo Bianchi ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Titanium Dioxide ◽  
Aqueous Solutions ◽  
Flow Rate ◽  
Substrate Concentration ◽  
Unit Length ◽  
Quantum Yields ◽  
Oxygen Donor ◽  
Reactor Geometry ◽  
Kinetics Of

Photomineralization of methane in air (10.0–1000 ppm (mass/volume) of C) at100%relative humidity (dioxygen as oxygen donor) was systematically studied at318±3 K in an annular laboratory-scale reactor by photocatalytic membranes immobilizing titanium dioxide as a function of substrate concentration, absorbed power per unit length of membrane, reactor geometry, and concentration of a proprietary vanadium alkoxide as photopromoter. Kinetics of both substrate disappearance, to yield intermediates, and total organic carbon (TOC) disappearance, to yield carbon dioxide, were followed. At a fixed value of irradiance (0.30 W⋅cm-1), the mineralization experiments in gaseous phase were repeated as a function of flow rate (4–400 m3⋅h−1). Moreover, at a standard flow rate of 300 m3⋅h−1, the ratio between the overall reaction volume and the length of the membrane was varied, substantially by varying the volume of reservoir, from and to which circulation of gaseous stream took place. Photomineralization of methane in aqueous solutions was also studied, in the same annular reactor and in the same conditions, but in a concentration range of 0.8–2.0 ppm of C, and by using stoichiometric hydrogen peroxide as an oxygen donor. A kinetic model was employed, from which, by a set of differential equations, four final optimised parameters,k1andK1,k2andK2, were calculated, which is able to fit the whole kinetic profile adequately. The influence of irradiance onk1andk2, as well as of flow rate onK1andK2, is rationalized. The influence of reactor geometry onkvalues is discussed in view of standardization procedures of photocatalytic experiments. Modeling of quantum yields, as a function of substrate concentration and irradiance, as well as of concentration of photopromoter, was carried out very satisfactorily. Kinetics of hydroxyl radicals reacting between themselves, leading to hydrogen peroxide, other than with substrate or intermediates leading to mineralization, were considered, and it is paralleled by a second competition kinetics involving superoxide radical anion.

Immobilization of Nano-TiO2 on Expanded Perlite for Photocatalytic Degradation of Rhodamine B

2011 ◽  
Vol 110-116 ◽  
pp. 3795-3800 ◽  
Author(s):  
Xiao Zhi Wang ◽  
Wei Wei Yong ◽  
Wei Qin Yin ◽  
Ke Feng ◽  
Rong Guo
Keyword(s):  
Catalytic Activity ◽  
Photocatalytic Degradation ◽  
Rhodamine B ◽  
Degradation Kinetics ◽  
Irradiation Time ◽  
Sol Gel ◽  
Polluted Water ◽  
Order Kinetic ◽  
Expanded Perlite ◽  
Initial Concentration

Expanded perlite (EP) modified titanium dioxide (TiO2) with different loading times were prepared by Sol-Gel method. Photocatalytic degradation kinetics of Rhodamine B (RhB) in polluted water by the materials (EP-nanoTiO2), as well as the effects of different loading times and the initial concentration of RhB on photocatalysis rate were examined. The catalytic activity of the regenerated photocatalyst was also tested. The results showed that photocatalyst modified three times with TiO2had the highest catalytic activity. Degradation ratio of RhB by EP-nanoTiO2(modified three times) under irradiation for 6 h were 98.0%, 75.6% and 63.2% for 10 mg/L, 20 mg/L and 30 mg/L, respectively.The photocatalyst activity has little change after the five times recycling, and the degradation rate of RhB decreased less than 8%. The reaction of photocatalysis for RhB with irradiation time can be expressed as first-order kinetic mode within the initial concentration range of RhB between 10mg/L and 30 mg/L. EP-nanoTiO2photocatalyst has a higher activity and stability to degrade RhB in aqueous solution.

scholarly journals Photocatalytic Degradation of Textile Dyeing Wastewater Using Titanium Dioxide and Zinc Oxide

2008 ◽  
Vol 5 (2) ◽  
pp. 219-223 ◽  
Author(s):  
Abbas J. Attia ◽  
Salih H. Kadhim ◽  
Falah H. Hussein
Keyword(s):  
Activation Energy ◽  
Zinc Oxide ◽  
Titanium Dioxide ◽  
Photocatalytic Degradation ◽  
Irradiation Time ◽  
Effect Of Temperature ◽  
Dyeing Wastewater ◽  
Textile Dyeing ◽  
Textile Factory ◽  
Textile Dyeing Wastewater

Photodegradation of a real textile dyeing wastewater taken from Hilla textile factory in Babylon Governorate, Iraq have been investigated. Photocatalytic degradation was carried out over suspensions of titanium dioxide or zinc oxide under ultraviolet irradiation. Photodegradation percentage was followed spectrophometrically by the measurements of absorbance at λmax equal to 380 nm. The rate of photodegradation increased linearly with time of irradiation when titanium dioxide or zinc oxide was used. A maximum color removal of 96% was achieved after irradiation time of 2.5 hours when titanium dioxide used at 303K and 82% color reduction was observed when zinc oxide used for the same period and at the same temperature. The effect of temperature on the efficiency of photodegradation of dyestuff was also studied. The activation energy of photodegradation was calculated and found to be equal to 21 ± 1 kJ mol-1 on titanium dioxide and 24 ± 1 kJ mol-1 on zinc oxide.

scholarly journals Enhanced Photocatalytic Degradation of Caffeine Using Titanium Dioxide Photocatalyst Immobilized on Circular Glass Sheets under Ultraviolet C Irradiation

Catalysts ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 964
Author(s):  
Rattana Muangmora ◽  
Patiya Kemacheevakul ◽  
Patiparn Punyapalakul ◽  
Surawut Chuangchote
Keyword(s):  
Titanium Dioxide ◽  
Photocatalytic Degradation ◽  
Tio2 Film ◽  
Irradiation Time ◽  
Anatase Phase ◽  
Treated Wastewater ◽  
Synthetic Wastewater ◽  
Coated Glass ◽  
Caffeine Degradation ◽  
Ultraviolet C

This work presents the development of titanium dioxide (TiO2) film immobilized on circular glass sheets for photocatalytic degradation of caffeine under ultraviolet C (UVC) irradiation. TiO2 was synthesized through the ultrasonic-assisted sol–gel method and immobilized on circular glass sheets by the doctor blade technique. Polyvinylpyrrolidone (PVP) was used to mix with the TiO2 precursor solution to enhance film adhesion on the glass surface. TiO2 film was mainly composed of anatase phase with a small amount of rutile phase. Caffeine removal was found to increase with increasing irradiation time. Caffeine (20 mg/L) in the synthetic wastewater could not be detected after 3 h of UVC irradiation. The reaction rate of caffeine degradation followed the pseudo-first-order model. The concentrated caffeine solutions required a longer irradiation time for degradation. The used TiO2-coated glass sheets could be easily separated from the treated wastewater and reusable. The caffeine removal efficiency of TiO2-coated glass sheets in each cycle maintained a high level (~100%) during fifteen consecutive cycles.

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