The detection methods and generation mechanisms of the intrinsic reactive oxygen species (ROS), i.e., superoxide anion radical (•O2–), hydrogen peroxide (H2O2), singlet oxygen (1O2), and hydroxyl radical (•OH) in photocatalysis, were surveyed comprehensively. Consequently, the major photocatalyst used in heterogeneous photocatalytic systems was found to be TiO2. However, besides TiO2 some representative photocatalysts were also involved in the discussion. Among the various issues we focused on the detection methods and generation reactions of ROS in the aqueous suspensions of photocatalysts. On the careful account of the experimental results presented so far, we proposed the following apprehension: adsorbed •OH could be regarded as trapped holes, which are involved in a rapid adsorption–desorption equilibrium at the TiO2–solution interface. Because the equilibrium shifts to the adsorption side, trapped holes must be actually the dominant oxidation species whereas •OH in solution would exert the reactivity...

Generation and Detection of Reactive Oxygen Species in Photocatalysis

Landfill leachate treatment: Review and opportunity

Ozonation of drinking water: part I. Oxidation kinetics and product formation.

http://repository.ias.ac.in/39608/1/49_pub.pdf

A review of imperative technologies for wastewater treatment I: oxidation technologies at ambient conditions

The potential occurrence of endocrine-disrupting compounds (EDCs) as well as pharmaceuticals and personal care products (PPCPs) in drinking water supplies raises concern over the removal of these compounds by common drinking water treatment processes. Three drinking water supplies were spiked with 10 to 250 ng/L of 62 different EDC/PPCPs; one model water containing an NOM isolate was spiked with 49 different EDC/PPCPs. Compounds were detected by LC/MS/MS or GC/MS/MS. These test waters were subjected to bench-scale experimentation to simulate individual treatment processes in a water treatment plant (WTP). Aluminum sulfate and ferric chloride coagulants or chemical lime softening removed some polyaromatic hydrocarbons (PAHs) but removed 98% of GC/MS/MS compounds (more volatile) and 10% to >95% of LC/MS/MS compounds (more polar); higher PAC dosages improved EDC/PPCP removal. EDC/PPCP per...

Fate of endocrine-disruptor, pharmaceutical, and personal care product chemicals during simulated drinking water treatment processes.

Stabilized leachates: sequential coagulation–flocculation + chemical oxidation process

Oxidation of atrazine in water by ultraviolet radiation combined with hydrogen peroxide

Stabilized leachates: ozone-activated carbon treatment and kinetics.

Advanced oxidation of atrazine in water—I. Ozonation

A kinetic model for the advanced oxidation (ozonation alone, UV radiation alone, ozone plus hydrogen peroxide, ozone plus UV radiation, and UV radiation plus hydrogen peroxide) of aromatic hydrocarbons in water is proposed and tested with experimental results of the oxidation of nitrobenzene and phenanthrene, two aromatic hydrocarbons of different reactivity with ozone. The kinetic model leads to good results in the case that the compound treated reacts exclusively with ozone, that is, without the contribution of hydroxyl radical oxidation as in the case of phenanthrene oxidation. In this case, it is not necessary to account for intermediate reactions to have good predictions of experimental remaining concentrations of ozonation processes. On the contrary, when the aromatic hydrocarbon s mainly removed by hydroxyl radicals (case of nitrobenzene), mole balance equations of intermediates have to be included for the experimental concentrations to be reproduced. For so doing, the kinetic parameters, such as rate constants of reactions between ozone and hydroxyl radical with intermediates and their corresponding quantum yields at 254 nm, were also determined. The kinetic model, however, is unable to reproduce, with accuracy, the experimental results of the ozone-UV radiation oxidation system.

Benito Acedo

Papers

Stabilized leachates: sequential coagulation–flocculation + chemical oxidation process

Oxidation of atrazine in water by ultraviolet radiation combined with hydrogen peroxide

Stabilized leachates: ozone-activated carbon treatment and kinetics.

Advanced oxidation of atrazine in water—I. Ozonation

A Kinetic Model for Advanced Oxidation Processes of Aromatic Hydrocarbons in Water: Application to Phenanthrene and Nitrobenzene