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The wastewater problem is becoming an increasingly significant environmental issue affecting various aspects of human activities. The generation of reactive oxygen species (ROS) in water through certain physicochemical processes, which can oxidise or degrade various organic and chemical compounds, offers an effective purification method. The main advantage of these methods is the elimination of chemical reagents. The aim of this work is to investigate the possibility of regulating the ROS content in water by altering the characteristics of the plasma discharge that occurs under hydrodynamic cavitation in the water flow. The ROS concentration was determined using the permanganate oxidation titration technique. It was found that the content of various reactive oxygen species in water after treatment can be controlled by varying the power of the electrical pulses applied. Additionally, this study obtained the dependence of the ROS concentration in treated water samples on storage time, with results indicating that sonoplasma treatment has a prolonged effect on the antibacterial properties of water. The analysis of water samples using a biological test culture of Salmonella typhimurium revealed the bacteriostatic properties of the water for at least 48 h after sonoplasma discharge treatment. [ABSTRACT FROM AUTHOR]

In this work, ZnO2 was unexpectedly discovered as a friendly and renewable source of anhydrous hydrogen peroxide in the acid-catalyzed synthesis of cyclic organic peroxides from carbonyl compounds. In particular, five classes of cyclic organic peroxides, namely, γ-hydroperoxy-γ-peroxylactones, β-hydroperoxy-β-peroxylactones, bridged ozonides, bridged 1,2,4,5-tetraoxanes, tricyclic monoperoxides, and tricyclic diperoxides, were synthesized in good yields using in situ generated H2O2 from the reaction of ZnO2 with H2SO4. This approach is convenient, safe, and does not require a concentrated aqueous or ethereal solution of H2O2. The starting ZnO2 was synthesized from zinc acetate using a 1 wt% H2O2 solution. The reaction of zinc peroxide with sulfuric acid in an organic solvent results in the release of hydrogen peroxide and the formation of zinc sulfate, which acts as a desiccant by forming a monohydrate phase, ZnSO4·H2O. The possibility of recycling zinc peroxide from zinc sulfate monohydrate with a high yield was shown. [ABSTRACT FROM AUTHOR]