Fenton chemistry encompasses reactions of hydrogen peroxide in the presence of iron to generate highly reactive species such as the hydroxyl radical and possibly others. In this review, the complex mechanisms of Fenton and Fenton-like reactions and the important factors influencing these reactions, from both a fundamental and practical perspective, in applications to water and soil treatment, are discussed. The review covers modified versions including the photoassisted Fenton reaction, use of chelated iron, electro-Fenton reactions, and Fenton reactions using heterogeneous catalysts. Sections are devoted to nonclassical pathways, by-products, kinetics and process modeling, experimental design methodology, soil and aquifer treatment, use of Fenton in combination with other advanced oxidation processes or biodegradation, economic comparison with other advanced oxidation processes, and case studies.

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Advanced Oxidation Processes for Organic Contaminant Destruction Based on the Fenton Reaction and Related Chemistry

Combination of Advanced Oxidation Processes and biological treatments for wastewater decontamination—A review

Advanced oxidation processes (AOPs) constitute a promising technology for the treatment of wastewaters containing non-easily removable organic compounds. Chlorophenols (CPs) are a group of special interest due to their high toxicity and low biodegradability. Data concerning the degradation of CPs by means of AOPs reported during the period 1995–2002 are evaluated in this work. Among the AOPs, the following techniques are studied: processes based on hydrogen peroxide (H2O2+UV, Fenton, photo-Fenton and Fenton-like processes), photolysis, photocatalysis and processes based on ozone (O3, O3+UV and O3+catalyst). Half-life times and kinetic constants for CP degradation are reviewed and the different mechanistic degradation pathways are taken into account.

Degradation of chlorophenols by means of advanced oxidation processes: a general review

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

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

Degradation and removal methods of antibiotics from aqueous matrices--a review.

The chemical treatment of cork-processing wastewater by ozonation, alone and in combination with hydrogen peroxide and UV radiation was investigated. A reduction of the chemical oxygen demand (COD) ranging from 42% to 76% was obtained during ozonation after 3 h of reaction, depending on the experimental conditions. The additional presence of hydrogen peroxide and UV radiation enhanced the efficiency of the ozonation treatment due to the contribution of the OH radicals formed in the decomposition of ozone. Thus, final reductions of the COD higher than 90% and a complete elimination of phenolic compounds and absorbance at 254 nm were achieved in both Advanced Oxidation Processes (AOPs), O3/H2O2 and O3/UV. Therefore the effluent resulting from the ozonation treatments can be reused in the cork-processing industry. In a second step, the chemical treatment was conducted by means of UV radiation alone and by the action of hydroxyl radicals, which were generated by the following AOPs: UV/H2O2, Fenton's reagent, and photo-Fenton system. The single photochemical process resulted in 9% of the organic matter present being removed, while the AOPs significantly enhanced this reduction with values in the range 20–75%. Kinetic studies for both groups of treatments were performed, and apparent kinetic rate constants were evaluated. In the ozone-based experiments, the rate constants ranged from 1846 to 10922 dm3 mol−1 O3 h−1, depending on the operating conditions. In the oxidation experiments using oxidants other than ozone, the rate constants varied between 0.06 and 1.19 h−1. Copyright © 2004 Society of Chemical Industry

Chemical treatment of cork-processing wastewaters for potential reuse

The oxidation by ozone and by the combination O3/H2O2 of four herbicides included in the acetamide group (acetochlor, metolachlor, propachlor, and butachlor) was studied. In a first step, the rate constants were determined for the reactions of the selected herbicides with ozone (kO3) and OH radicals (kOH). The sequence of reactivities for solutions in ultrapure water were as follows:  for ozonation, metolachlor < propachlor < acetochlor < butachlor; for oxidation by hydroxyl radicals, propachlor < acetochlor < metolachlor < butachlor. The rate constants for the reaction with ozone ranged from 1.1 to 5.3 L/(mol·s), indicating that direct reactions with ozone will play a minor role during ozonation processes. Values for kOH ranged from 4.6 × 109 to 7.4 × 109 L/(mol·s). Therefore, reactions with OH radicals will be the major pathway for the oxidative transformation of these four herbicides, even when conventional ozonation is applied. In a second step, the oxidation of the investigated herbicides during ozon...

Oxidation of Acetamide Herbicides in Natural Waters by Ozone and by the Combination of Ozone/Hydrogen Peroxide: Kinetic Study and Process Modeling

The chemical oxidation of the organic matter in olive mill wastewaters by the advanced oxidation process ozone plus UV radiation is studied to evaluate the increase in degradation in relation to ozonation alone. Also, the effect of the UV radiation alone on the oxidation is established. The destruction of the organic material was followed by the disappearance of the chemical oxygen demand (COD), the total aromatic compounds and the total phenolics. An approximate kinetic study is developed, the apparent kinetic constants with respect to the phenolic compounds being determined in both processes, the single photochemical and the combined ozone‐UV radiation.

Treatments of wastewaters from olive oil mills by uv radiation and by combined ozone‐UV radiation

Two representative substances of the so-called emerging compounds group (ECs), N,N-diethyl-m-toluamide (DEET) and nortriptyline hydrochloride, were selected to be subjected to ozonation processes, which constitute promising technologies for the removal of hazardous pollutants. The kinetic study provided ozonation rate constants, with an average value of 0.123 ± 0.003 L·mol–1·s–1 for DEET, which remained almost unaffected with the pH; while values varying from 2.40 × 103 to 472 × 103 L·mol–1·s–1 for nortriptyline were deduced in the pH range 2–11. Because of the ionic nature of nortriptyline, the specific rate constants of the protonated and neutral species were determined, the values obtained being 2.1 × 103 and 4.3 × 105 L·mol–1·s–1, respectively. By means of liquid chromatography time-of-flight mass spectrometry analysis, the main byproducts formed in the ozonation reactions were identified (14 for DEET and 27 for nortriptyline), and the evolution of their concentrations with reaction time were establis...

F. Javier Benitez

Papers

Chemical treatment of cork-processing wastewaters for potential reuse

Oxidation of Acetamide Herbicides in Natural Waters by Ozone and by the Combination of Ozone/Hydrogen Peroxide: Kinetic Study and Process Modeling

Treatments of wastewaters from olive oil mills by uv radiation and by combined ozone‐UV radiation

Determination of the Reaction Rate Constants and Decomposition Mechanisms of Ozone with Two Model Emerging Contaminants: DEET and Nortriptyline

Kinetics of the reaction between ozone and MCPA