Studies of oxidations by fenton's reagent using redox titration. V. Effect of complex formation on reaction mechanism

1973 ◽  
Vol 26 (5) ◽  
pp. 1021 ◽  
Author(s):  
DL Ingles
Keyword(s):  
Reaction Mechanism ◽  
Complex Formation ◽  
Hydroxyl Radical ◽  
Butyl Alcohol ◽  
Fenton’S Reagent ◽  
Redox Titration ◽  
Fenton's Reagent ◽  
Free Hydroxyl ◽  
Electron Transfers ◽  
H2o2 System

The effect of complex formation on the oxidation of substrate in the Fe2+-H2O2 system has been studied. t-Butyl alcohol which is normally oxidized to the dimer, 2,5-dimethylhexane-2,5-diol, by Fenton's reagent has been used as a probe for the presence of free hydroxyl radical. ��� It is shown that when suitable complexes are formed substrates are not oxidized by free hydroxyl radical. Instead, new mechanisms involving one- and two-electron transfers within a substrate-ferrous ion-peroxide complex are proposed.

Studies of oxidations by fenton's reagent using redox titrations. IV. Oxidation of ethanol and t-butyl alcohol

1973 ◽  
Vol 26 (5) ◽  
pp. 1015 ◽  
Author(s):  
DL Ingles
Keyword(s):  
Reaction Rates ◽  
Butyl Alcohol ◽  
Oxidation Products ◽  
Fenton’S Reagent ◽  
Copper Salts ◽  
Redox Titration ◽  
Fenton's Reagent ◽  
Titration Procedure ◽  
Free Hydroxyl ◽  
Oxidation Of Ethanol

The oxidation of ethanol by Fenton's reagent was studied to confirm the validity of the redox titration procedure. A quantitative analysis of oxidation products during the complete oxidation of ethanol and its consecutive oxidation products is presented. � The oxidation of t-butyl alcohol was studied under a number of different conditions and yields of acetone and the dimer, 2,5- dimethylhexane-2,5-diol, were obtained. The effects of oxygen, copper salts, and chloride and bromide ions on this oxidation were studied. ��� The ratio of reaction rates of ethanol and t-butyl alcohol with the free hydroxyl radical was determined.

Influence of pH on the dewatering of activated sludge by Fenton's reagent

2001 ◽  
Vol 44 (10) ◽  
pp. 327-332 ◽  
Author(s):  
M.-C. Lu ◽  
C.-J. Lin ◽  
C.-H. Liao ◽  
W.-P. Ting ◽  
R.-Y. Huang
Keyword(s):  
Control Experiment ◽  
Treatment Plant ◽  
Fenton’S Reagent ◽  
Excess Sludge ◽  
Fenton's Reagent ◽  
Initial Ph ◽  
And Control ◽  
Sludge Settling ◽  
Influence Of Ph ◽  
H2o2 System

The specific filtration resistance, moisture, and SVI were used to evaluate the influence of pH on the filtration and dewatering efficiencies when applying Fenton's reagent to treat the excess sludge. The excess sludge used in this study was obtained from the wastewater treatment plant of An-Ping Industrial Park in Tainan, Taiwan. Results show that initial pH has no significant effect on the filtration efficiency of sludge by using the Fenton (Fe2+/H2O2) system as the treatment process. However, the reduction of specific resistance by Fenton-like (Fe3+/H2O2) process decreased suddenly to a level similar to that obtained from the control experiment at initial pH > 4.5. For the moisture of cake sludge, both Fenton and Fenton-like systems have the same tendency; the moisture of cake sludge increased slightly with increasing the initial pH. The SVI values for Fenton process decreased with increasing the initial pH, but the opposite result was obtained from the Fenton-like and control system; higher pH was not favorable for the sludge settling.

Studies of oxidation by fenton's reagent using redox titration. I. Oxidation of some organic compounds

1972 ◽  
Vol 25 (1) ◽  
pp. 87 ◽  
Author(s):  
DL Ingles
Keyword(s):  
Organic Compounds ◽  
Organic Substrate ◽  
Oxidation Potential ◽  
Oxidation Products ◽  
Fenton’S Reagent ◽  
Complete Oxidation ◽  
Redox Titration ◽  
Fenton's Reagent

Oxidations using Fenton's reagent have not been followed previously by redox titration. This procedure assists in defining the overall reaction and allows both an estimate of relative rates of oxidation and a measure of the consumption of peroxide by the organic substrate. The peroxide consumed in the complete oxidation of substrate to inactive compounds has been measured by titration at constant oxidation potential. Such measurements reflect the peroxide consumed by the substrate and its consecutive oxidation products and may therefore be used to assess the significance of oxidation pathways.

scholarly journals Surface Modification of Polyethylene Film by Catalytic Ozonation

2021 ◽  
Author(s):  
Erlita Mastan
Keyword(s):  
Reaction Mechanism ◽  
Hydroxyl Radical ◽  
Membrane Filtration ◽  
Low Cost ◽  
Polymer Surface ◽  
Butyl Alcohol ◽  
Catalytic Ozonation ◽  
Polymer Surfaces ◽  
Polyethylene Film ◽  
Radical Scavenger

The hydrophobicity of polymer surfaces limits their applications in many areas such as for use as biomaterials and in membrane filtration. One solution to this problem is to modify the polymer surface by ozonation. Ozonation introduces peroxide groups on polymer surface, which can initiate graft polymerization of monomers with hydrophilic groups, and thus improves the hydrophilicity of the polymer surfaces. The concentration of peroxide groups formed can be used to indicate the effectiveness of ozonation process. In this study, the low cost polyethylene film was selected as a model polymer film to conduct the investigation. Ozonation treatment was carried out in both gaseous and aqueous phases, to study the contribution of hydroxyl radical in the generation of peroxide group. Results revealed that aqueous ozonation generated slightly less peroxide than gaseous ozonation. However, the addition of soluble catalyst, copper (II) sulfate, to the aqueous ozonation resulted in 18% more peroxide concentration than that yielded by gaseous ozonation. Further investigation indicated that 0.05 g/L copper (II) sulfate was the optimal catalyst dose, and the optimal pH was approximately 5.60. A 19% reduction in tensile strength of the film was observed after 120 minutes of catalytic ozonation. Upon addition of a radical scavenger, tert-butyl alcohol (TBA), a decrease of 12% in the peroxide concentration was observed for catalytic ozonation with 0.1 mol/L TBA. This decrease indicated that both ozone and hydroxyl radical contributed to the peroxide generation in catalytic ozonation. A reaction mechanism for aqueous ozonation of polyethylene was proposed in this study by combining the reaction mechanism for gaseous ozonation of polyethylene and the decomposition mechanism of ozone in water. The experimental data found in this study verified the exponential function obtained for peroxide concentration. This verification was obtained for various ozonation time and dose ranging from 15 – 120 minutes and 1.0 – 3.0 wt%, respectively.

Reactions of Hydroxyl Radicals with Chlorobenzenes: Comparison of TiO2 Photocatalyst Reactions to Fenton’s Reagent

1989 ◽  
Vol 24 (4) ◽  
pp. 537-552 ◽  
Author(s):  
G. Lepore ◽  
C.H. Langford
Keyword(s):  
Hydroxyl Radical ◽  
Hydroxyl Radicals ◽  
Aqueous Media ◽  
Surface Generation ◽  
Fenton’S Reagent ◽  
Adsorbed State ◽  
Fenton's Reagent ◽  
Photo Catalysis ◽  
Solution Generation ◽  
The Individual

Abstract A comparative study on reactions of solution and surface generated hydroxyl radicals with chlorobenzenes has been carried out, to determine the reaction path of reactive intermediates in photo-catalysis. Two separate approaches for generating hydroxyl radical oxidants in aqueous media were employed. Fenton’s reagent (solution generation) and TiO2 irradiation (surface generation) were exploited in the decomposition of dichlorobenzenes, 1,2,4-trichlorobenzene and a mixture (o-DCB, m-DCB, 1,2,4-TCB). Photocatalysis displayed a distinctive order for the individual chlorobenzenes with increasing ease of disappearance: p-DCB < 1,2,4-TCB < o-DCB < m-DCB. Reduced selectivity was observed for a mixture. Use of Fenton’s reagent resulted in the following pattern for both individual and the mixture of chlorobenzenes: 1,2,4-TCB < o-DCB ≈ p-DCB ≈ m-DCB. Added acetone, suppressed the disappearance of the parent chlorinated aromatics in both systems. However, in the reaction with Fenton’s reagent 1,2,4-TCB displayed considerable sensitivity in comparison to the DCB isomers. In contrast, the photocatalysis of three individual substrates evaluated in a mixture (1,2,4-TCB, m-DCB, o-DCB) did not manifest significant differences. Results indicate that reactions observed on the photocatalyst must occur in the adsorbed state, where the oxidant is an adsorbed hydroxyl radical or the surface trapped hole itself.

Studies of oxidations by Fenton's reagent using redox titration. II. Effect of oxygen

1972 ◽  
Vol 25 (1) ◽  
pp. 97 ◽  
Author(s):  
DL Ingles
Keyword(s):  
Gas Chromatography ◽  
Oxidation Potential ◽  
Fenton’S Reagent ◽  
Complete Oxidation ◽  
Redox Titration ◽  
Fenton's Reagent ◽  
Chain Reactions ◽  
Effect Of Oxygen

The effect of oxygen on oxidations by Fenton's reagent has been studied by redox titration at constant oxidation potential. The reactivity of substrate radicals towards oxygen has been assessed. The peroxide requirements for the complete oxidation of substrate in the absence and presence of oxygen have been compared. The extent of oxidation of different substrates was determined by gas chromatography and the results indicated the occurrence, in oxygen, of nem chain reactions.

scholarly journals Surface Modification of Polyethylene Film by Catalytic Ozonation

2021 ◽  
Author(s):  
Erlita Mastan
Keyword(s):  
Reaction Mechanism ◽  
Hydroxyl Radical ◽  
Membrane Filtration ◽  
Low Cost ◽  
Polymer Surface ◽  
Butyl Alcohol ◽  
Catalytic Ozonation ◽  
Polymer Surfaces ◽  
Polyethylene Film ◽  
Radical Scavenger

The hydrophobicity of polymer surfaces limits their applications in many areas such as for use as biomaterials and in membrane filtration. One solution to this problem is to modify the polymer surface by ozonation. Ozonation introduces peroxide groups on polymer surface, which can initiate graft polymerization of monomers with hydrophilic groups, and thus improves the hydrophilicity of the polymer surfaces. The concentration of peroxide groups formed can be used to indicate the effectiveness of ozonation process. In this study, the low cost polyethylene film was selected as a model polymer film to conduct the investigation. Ozonation treatment was carried out in both gaseous and aqueous phases, to study the contribution of hydroxyl radical in the generation of peroxide group. Results revealed that aqueous ozonation generated slightly less peroxide than gaseous ozonation. However, the addition of soluble catalyst, copper (II) sulfate, to the aqueous ozonation resulted in 18% more peroxide concentration than that yielded by gaseous ozonation. Further investigation indicated that 0.05 g/L copper (II) sulfate was the optimal catalyst dose, and the optimal pH was approximately 5.60. A 19% reduction in tensile strength of the film was observed after 120 minutes of catalytic ozonation. Upon addition of a radical scavenger, tert-butyl alcohol (TBA), a decrease of 12% in the peroxide concentration was observed for catalytic ozonation with 0.1 mol/L TBA. This decrease indicated that both ozone and hydroxyl radical contributed to the peroxide generation in catalytic ozonation. A reaction mechanism for aqueous ozonation of polyethylene was proposed in this study by combining the reaction mechanism for gaseous ozonation of polyethylene and the decomposition mechanism of ozone in water. The experimental data found in this study verified the exponential function obtained for peroxide concentration. This verification was obtained for various ozonation time and dose ranging from 15 – 120 minutes and 1.0 – 3.0 wt%, respectively.

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