Kinetics and pathways of the degradation of PPCPs by carbonate radicals in advanced oxidation processes

Three Kinetic Patterns for the Oxidation of Emerging Organic Contaminants by Fe(VI): The Critical Roles of Fe(V) and Fe(IV)

“…Emerging organic contaminants (EOCs) are a group of synthetic compounds widely present in the aquatic environment, as a consequence of various industrial and agricultural activities of human beings . Although the concentrations of EOCs are commonly observed at trace concentrations (typically ng L –1 or μg L –1 ), they have attracted increasing concerns due to their potential human and ecological health risks. − Notably, chemical oxidation is one of the most effective approaches to alleviate EOCs in raw water or municipal wastewater effluents. − Among the commonly used chemical oxidants, ferrate (i.e., Fe­(VI)) has attracted increasing attention in recent years due to its multiple functions − and great superiority over other oxidants in suppressing the formation of some specific disinfection byproducts . Fe­(VI) can not only effectively decompose various organic contaminants, − especially those containing electron-donating moieties, but also sequester the degradation products of target organic contaminants through coagulation and/or adsorption due to the in situ generation of Fe­(III). ,, Although Fe­(VI) can slowly oxidize bromide, the formation of active bromine and bromate at typical water treatment conditions is limited without a public health concern. , Over the past decades, oxidative removal of various EOCs in water by Fe­(VI) has been extensively investigated, including quantitatively determining the kinetics of EOCs degradation. − Generally, it was believed that Fe­(VI) oxidation of a specific EOC followed second-order kinetics behaviors, i.e., first-order dependence on the concentrations of both Fe­(VI) and the target EOC (eq ).…”

Comparative study of degradation of ketoprofen and paracetamol by ultrasonic irradiation: Mechanism, toxicity and DBP formation

“…A positive effect of HCO 3 − was also observed during the ultrasonic degradation process [19] , [35] . Compared with •OH, CO 3 ●− is a more selective oxidant that can readily react with electron-rich compounds containing aniline, phenolic hydroxyl groups and naphthalene rings [36] . According to Mahdi et al, the self-recombination of •OH would occur when the concentration of the target pollutant is low, and the self-recombination rate of CO 3 ●− (2 × 10 7 M −1 s −1 ) is far less than that of •OH (5.5 × 10 9 M −1 s −1 ) [35] .…”

Misconceptions about the chemistry of aqueous chlorine atoms and HClOH˙(aq), and a revised mechanism for the photochemical peroxydisulfate/chloride reaction

“…11 Here we report an additional 37 publications that have mechanisms including this loop. 51,64,65,[67][68][69][70][71][81][82][83]85,[87][88][89][90][92][93][94][95]97,[99][100][101][102][103][104][105][106][108][109][110][111][112][113]118,119 In our previous report we showed that correcting Loop ''D'' by supplying the requisite value for the reverse rate constant in the first step had no effect on the simulations of the overall mechanism in one of the publications. This outcome was traced to the fact that the first step could be eliminated entirely without affecting the results of the simulation.…”