Reaction of hydroxyl and oxygen(-) radicals with aromatic carboxylate anions in aqueous solutions

Tailored photocatalysts and revealed reaction pathways for photodegradation of polycyclic aromatic hydrocarbons (PAHs) in water, soil and other sources

Polycyclic aromatic hydrocarbons (PAHs), which are in the class of persistent organic pollutants, are considered as hazardous pollutants. To date, these compounds were detected globally in soil, sludge, water, and other contamination sources. A variety of treatment methods have been used in recent years to degrade PAHs in the environment. Photocatalysis, among advanced techniques, is proposed as the most effective method for the treatment of PAHs. In this context, we introduce the classification of PAHs, summarize, and highlight the recent studies on photodegradation of various types of PAHs. A series of efficient photocatalysts, including TiO₂-, Ag₃PO₄-, ZnO-, MHCFs-based, and others, have been reported with the potential result for photodegradation of PAHs. Focus is also placed on revealing several possible reaction pathways for different types of PAHs that have been proposed in the literature. Particular attention to current status, challenges, and prospects in the future for enhanced photodegradation of PAHs are also discussed.

γ-Radiation and H2O2 induced oxidative dissolution of uranium(iv) oxide in aqueous solution containing phthalic acid

This study aims to reveal possible involvements of organic acids in the oxidative dissolution of UO2. Using phthalic acid as a model compound, we have measured adsorption on UO2 and investigated effects on the reaction between H2O2 and UO2 and on oxidative dissolution induced by γ-irradiation. Significant adsorption of phthalic acid was observed even at neutral pH. However, the reaction between H2O2 and UO2 in phthalic acid solution induced oxidative dissolution of U(vi) similar to in aqueous bicarbonate solution. Moreover, degradation products of phthalic acid were not detected after the reaction of H2O2. These results indicate that even though phthalic acid adsorbs on the UO2 surface, it is not involved in the interfacial reaction of H2O2. In contrast, the dissolution of U by irradiation was inhibited in aqueous phthalic acid solution, whereas H2O2 generated by radiolysis was consumed by UO2. Based on these contrasting results, possible roles of radical species generated by water radiolysis were discussed.

Experimental and theoretical studies on aqueous-phase reactivity of hydroxyl radicals with multiple carboxylated and hydroxylated benzene compounds

In this study, we shed light on the initial addition of hydroxyl radicals (HO˙) to multiple carboxylated and hydroxylated benzene compounds in aqueous-phase advanced oxidation processes (AOPs).