Hydrogen peroxide

About: Hydrogen peroxide is a research topic. Over the lifetime, 42583 publications have been published within this topic receiving 1043732 citations. The topic is also known as: H2O2 & dioxidane.

The Photochemical Generation of Hydroxyl Radicals in the UV-vis/ Ferrioxalate/H2O2 System

Abstract: A reaction mechanism has been validated for the photochemical generation of hydroxyl radicals by ultraviolet or visible irradiation of oxalato iron(III) complexes (ferrioxalate) in the presence of hydrogen peroxide and 2-propanol as a model substrate. A kinetic simulation program incorporating the set of reactions was written to predict the behavior of this photochemical system. The program calculates the quantum yield of oxidation of 2-propanol used as a hydroxyl radical scavenger. The scavenger's oxidation product, 2-propanone, was analyzed by gas chromatog raphy after controlled exposure of the solution to a calibrated light source. The theoretical quantum yields of 2-propanol oxidation, ΦRH, agreed reasonably well with experimentally determined ΦRH values under a variety of initial reaction conditions. The value of ΦRH, which under appropriate conditions is directly proportional to the quantum yield for the generation of hydroxyl radicals, ΦOH, was considerably greater than unity in most cases (often ...

Glutathione peroxidase in lens and a source of hydrogen peroxide in aqueous humour.

Abstract: 1. Glutathione peroxidase has been demonstrated in cattle, rabbit and guineapig lenses. 2. The enzyme will oxidize GSH either with hydrogen peroxide added at the start of the reaction or with hydrogen peroxide generated enzymically with glucose oxidase. 3. No product other than GSSG was detected. 4. Oxidation of GSH can be coupled with oxidation of malate through the intermediate reaction of glutathione reductase and NADPH2. 5. Traces of hydrogen peroxide are present in aqueous humour: it is formed when the ascorbic acid of aqueous humour is oxidized. 6. Hydrogen peroxide will diffuse into the explanted intact lens and oxidize the contained GSH. The addition of glucose to the medium together with hydrogen peroxide maintains the concentration of lens GSH. 7. Glutathione peroxidase in lens extracts will couple with the oxidation of ascorbic acid. 8. It is suggested that, as there is only weak catalase activity in lens, glutathione peroxidase may act as one link between the oxygen of the aqueous humour and NADPH2.

Zero-Valent Aluminum for Oxidative Degradation of Aqueous Organic Pollutants

Abstract: Oxidative degradation of aquatic organic contaminants using zero-valent aluminum (ZVAl) in the presence of dissolved oxygen (O2) was investigated. The metal corrosion process in acidic conditions (pH <4) was accompanied by electron transfer from ZVAl to O2, which led to the simultaneous generation of Al3+ and hydrogen peroxide (H2O2). The oxidation of 4-chlorophenol (4-CP), a model substrate, was initiated by the generation of hydroxyl radicals (HO•) via electron transfer from Al0 to H2O2. Degradation was initiated after an induction period of about 2 h, during which the native oxide layer was dissoluted. The HO•-mediated oxidation reaction was completely quenched by adding methanol as a radical scavenger. Systematic studies on the effects of ZVAl loading, pH, and surface oxide content revealed that the oxide layer dissolution controlled the Al0-mediated oxidation of 4-CP. The proposed process is similarly compared with the zero-valent iron (ZVI) system, but the ZVAl/O2 system showed a higher oxidation ca...