Catalytic effect of cetyltrimethylammonium bromide on the radical destruction oxidation of pyrocatechol violet

1980 ◽  
Vol 45 (11) ◽  
pp. 2883-2889 ◽  
Author(s):  
Jan Lasovský ◽  
František Březina ◽  
Ladislav Nekl
Keyword(s):  
Hydrogen Peroxide ◽  
Rate Constants ◽  
Cetyltrimethylammonium Bromide ◽  
Optimum Conditions ◽  
Pyrocatechol Violet ◽  
Radical Oxidation ◽  
Experimental Rate ◽  
Cobalt Compounds ◽  
Cobalt Dichloride ◽  
Usual Formalism

The effect of cetyltrimethylammonium bromide (I) on the radical oxidation of pyrocatechol violet by hydrogen peroxide was studied in the presence of N,N'-ethylenediamine-bis(o-aminobenzaldimine)cobalt(II) bromide and cobalt dichloride. After a short, faster period the reaction obeys the 1st order formalism. In the presence of I the experimental rate constants are as much as 42 times higher than in "pure" solutions. In optimum conditions (dye concentration 1.75 . 10-4 mol l-1) the reaction can be described in terms of the usual formalism of micellar catalysis. In solutions containing I the effect of cobalt compounds can be traced down to cobalt concentration levels of 10-8 mol l-1. The dependences of the experimental rate constants on the concentrations of hydrogen peroxide and cobalt compounds and on the temperature and pH are discussed.

TREATABILITY OF 2,4-D PRODUCTION WASTEWATERS

1994 ◽  
Vol 30 (3) ◽  
pp. 73-78 ◽  
Author(s):  
O. Tünay ◽  
S. Erden ◽  
D. Orhon ◽  
I. Kabdasli
Keyword(s):  
Hydrogen Peroxide ◽  
Activated Sludge ◽  
Partial Oxidation ◽  
Chloride Concentration ◽  
Chemical Oxidation ◽  
Cod Removal ◽  
Optimum Conditions ◽  
Organic Loading ◽  
Activated Sludge System ◽  
Biological Treatability

This study evaluates the characterization and treatability of 2,4-D production wastewaters. Wastewaters contain 20000-40000 mg/l COD, 17000-30000 mg/l chloride and pH is around 1.0. Chemical oxidation with hydrogen peroxide provided almost complete COD removal. The optimum conditions are 3:1 H2O2/COD oxidant dosage, 3000 mg/l Fe3+ as catalyst and pH 3. Partial oxidation at 0.5:1 H2O2//COD ratio is also effective providing 67% COD removal. A batch activated sludge system is used for biological treatability. Dilution is needed to maintain a tolerable chloride concentration which increases through COD removal. pH also increased during COD removal. 85% COD removal is obtained for the 50% dilution at an organic loading of 0.3 day‒1 on a COD basis. Completely and partially oxidized wastewaters are also treated in the activated sludge down to 30 mg/l BOD5.

Separation of Aflatoxin-Contaminated Kernels from Sound Kernels by Hydrogen Peroxide Treatment

1993 ◽  
Vol 56 (2) ◽  
pp. 130-133 ◽  
Author(s):  
Ma. R. S. CLAVERO ◽  
Y.-C. HUNO ◽  
L. R. BEUCHAT ◽  
T. NAKAYAMA
Keyword(s):  
Hydrogen Peroxide ◽  
Maximum Yield ◽  
Optimum Conditions ◽  
Total Aflatoxin ◽  
Aflatoxin Content ◽  
Treatment Conditions ◽  
Hydrogen Peroxide Treatment ◽  
Low Concentrations ◽  
Order Polynomial ◽  
Contour Plots

Blends (0:1, 1:3, 1:1, and 3:1, wt/wt) of aflatoxin-contaminated and sound peanut kernels were submerged for 1, 2, and 3 min in various concentrations of hydrogen peroxide solution. The effectiveness of these treatments in separating aflatoxin-contaminated kernels from sound kernels was determined. Peanuts that floated (floaters) and those that did not (sinkers) were subjected to aflatoxin analysis. Second order polynomial equations were satisfactorily fitted to the experimental data. Hydrogen peroxide concentrations of 0.075, 0.150, and 0.25% resulted in a reduction in aflatoxin content in the kernels in the sinker fraction by 90% within 1 min, regardless of the initial aflatoxin content. The total aflatoxin content in sinker and floater fractions was approximately the same as that in unfractionated samples, indicating that the low concentrations of hydrogen peroxide in treatment solutions did not degrade aflatoxin. Response surface methodology was used to generate contour plots which revealed optimum treatment conditions for giving a maximum yield of the sinker fraction with low aflatoxin content. For peanuts containing 50 ppb aflatoxin, optimum conditions consist of a 0.08% hydrogen peroxide treatment for 0.7 min. This procedure results in a maximum sinker fraction yield of 85.5% of the original lot with a residual aflatoxin content of ≤5 ppb.

Studies of radiation-induced reactions of ethylene in aqueous solution II. Reactions in the presence of oxygen as studied by pulse radiolysis and γ -irradiation techniques

1967 ◽  
Vol 300 (1463) ◽  
pp. 443-454 ◽  
Keyword(s):  
Aqueous Solution ◽  
Hydrogen Peroxide ◽  
Rate Constants ◽  
Pulse Radiolysis ◽  
Major Product ◽  
Peroxy Radicals ◽  
Ferrous Ions ◽  
Constant Composition ◽  
Γ Irradiation ◽  
Radiation Induced

The radiolysis of dilute aqueous solutions containing ethylene and oxygen has been investigated. Pulse radiolysis was used to measure the rate constants for the addition of hydroxyl radicals to ethylene, the binary decomposition of the resulting hydroxyethyl radicals and their addition to ethylene and reaction with oxygen to yield peroxy radicals. The rate constants have also been determined for the mutual interaction of the peroxy radicals and their reaction with ferrous ions. The principal products of γ -irradiation were aldehydes and organic hydroperoxides. Hydrogen peroxide was found in yields close to the molecular yield from water. The polymer produced in the absence of oxygen was not formed, and glycollaldehyde, reported as a major product by previous workers, could not be detected. At constant composition of the gas mixtures, product yields were unaffected by total pressure in the range up to 40 atm, but were strongly dependent on the proportion of oxygen. Aldehyde yields were markedly greater at pH 1.2 than in neutral solution. The influence of ferrous ions an d of added hydrogen peroxide has been determined. The pulse radiolysis and γ -irradiation experiments complement one another and show that the radiation-induced oxidation of ethylene in aqueous solution involves the same primary reactions as occur in the absence of oxygen, followed by the formation and further reactions of peroxy radicals.

Reactions of yeast thioredoxin peroxidases I and II with hydrogen peroxide and peroxynitrite: Rate constants by competitive kinetics

2007 ◽  
Vol 42 (3) ◽  
pp. 326-334 ◽  
Author(s):  
Renata Ogusucu ◽  
Daniel Rettori ◽  
Daniela Cristina Munhoz ◽  
Luis Eduardo Soares Netto ◽  
Ohara Augusto
Keyword(s):  
Hydrogen Peroxide ◽  
Rate Constants ◽  
Competitive Kinetics

scholarly journals Kinetic Study of Photocatalytic Degradation of Tolonium Chloride Under High Pressure Irradiation in Aquatic Buffer Systems

2011 ◽  
Vol 8 (s1) ◽  
pp. S19-S26 ◽  
Author(s):  
M. Montazerozohori ◽  
S. Nezami ◽  
S. Mojahedi
Keyword(s):  
High Pressure ◽  
Photocatalytic Degradation ◽  
Kinetic Study ◽  
Rate Constants ◽  
Order Kinetic ◽  
Optimum Conditions ◽  
First Order ◽  
Reactor Cell ◽  
Order Kinetic Model ◽  
Tolonium Chloride

Anatase titanium dioxide catalyzed photodegradation of tolonium chloride at various bufferic pH of 2, 7, 9 and 12 in aqueous solution is presented. The effect of some physicochemical parameters such as initial concentration of dye, catalyst amount and reaction time on photocatalytic degradation has been investigated in a photo-reactor cell containing high pressure mercury lamp to obtain the optimum conditions in each bufferic pH at constant temperature. A complete spectrophotometric kinetic study of tolonium chloride under high pressure irradiation at buffer media was performed. The photocatalytic degradation observed rate constants (kobs) were found to be 2.90×10-3, 3.30×10-3, 3.20×10-3and 5.20×10-3min-1for buffer pH of 2-12 respectively. It was found that a pseudo-first-order kinetic model based on Langmuir-Hinshelwood one is usable to photodegradation of this compound at all considered buffer pH. In addition to these, the Langmuir-Hinshelwood rate constants, krfor the titled compound at various pH are reported.

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