Hydrogen Peroxide Formation during Ozonation of Olefins and Phenol: Mechanistic Insights from Oxygen Isotope Signatures.

Mitigation of undesired byproducts from ozonation of dissolved organic matter (DOM) such as aldehydes and ketones is currently hampered by limited knowledge of their precursors and formation pathways. Here, the stable oxygen isotope composition of HO formed simultaneously with these byproducts was studied to determine if it can reveal this missing information. A newly developed procedure, which quantitatively transforms HO to O for subsequent O/O ratio analysis, was used to determine the δO of HO generated from ozonated model compounds (olefins and phenol, pH 3-8).

A Tale of Two Treatments: The Multiple Barrier Approach to Removing Chemical Contaminants During Potable Water Reuse.

In response to water scarcity and an increased recognition of the risks associated with the presence of chemical contaminants, environmental engineers have developed advanced water treatment systems that are capable of converting municipal wastewater effluent into drinking water. This practice, which is referred to as potable water reuse, typically relies upon reverse osmosis (RO) treatment followed by exposure to ultraviolet (UV) light and addition of hydrogen peroxide (HO). These two treatment processes individually are capable of controlling many of the chemical and microbial contaminants in wastewater; however, a few chemicals may still be present after treatment at concentrations that affect water quality.

Degradation rates of benzotriazoles and benzothiazoles under UV-C irradiation and the advanced oxidation process UV/H2O2.

Benzotriazoles (BTs) and benzothiazoles (BTHs) are extensively used chemicals found in a wide range of household and industrial products. They are chemically stable and are therefore ubiquitous in the aquatic environment. The present study focuses on the potential of ultraviolet (UV) irradiation, alone or in combination with hydrogen peroxide (H2O2), to remove BTs and BTHs from contaminated waters.

Kinetic and mechanistic investigations of the oxidation of tramadol by ferrate and ozone.

The kinetics and oxidation products (OPs) of tramadol (TRA), an opioid, were investigated for its oxidation with ferrate (Fe(VI)) and ozone (O(3)). The kinetics could be explained by the speciation of the tertiary amine moiety of TRA, with apparent second-order rate constants of 7.4 (±0.

Reductive Dissolution of Fe(III) (Hydr)oxides by Cysteine: Kinetics and Mechanism.

Cysteine was used as a model reductant to gain further insight into the kinetics of bacterially mediated iron reduction. Our experimental data and modeling results indicated that the reductive dissolution of hydrous ferric oxide (HFO) takes place via surface complex formation of cysteine and corresponds to the rate law d[Fe(II)]/dt = k20[ identical withFecys-] + k21[ identical withFecys0], where k20 and k21 are the corresponding rate constants for the cysteine surface species identical withFecys- and identical withFecys0, respectively. The pH-dependent dissolution behavior of HFO suggested that k20[ identical withFecys-] >> k21[ identical withFecys0].