Catalytic oxidation of thiocyanates in an acid medium

Fundamental aspects of the oxidative destruction of thiocyanates by hydrogen peroxide in an acid medium in the presence of a catalyst, iron(III) ions, was studied. The effect of copper(II) ions on the mechanism and kinetics of SCN-oxidation in the presence of thiosulfates was considered.     

Electrochemical oxidation of phenols

Electrochemical oxidation of chlorinated phenols was studied.     

Effect of anions on the oxidation of organic compounds with ultrasonically activated persulfate

The effect of anions typically present in natural and waste waters on the oxidation of the azo dye methyl orange with persulfate activated with high-frequency ultrasound was studied. At a chloride concentration of 1 mmol/L, the rate constant of substrate oxidation increased 1.5-fold, but further increase in the chloride content retarded the process. The addition of nitrates, carbonates, and hydrogen carbonates to the solution inhibited the process (NO₃^- < HCO₃^- ~ CO₃^2-). These tendencies were in good agreement with the results obtained on a real water matrix of the natural surface water from Lake Baikal.     

Effect of Hydrocarbonates and Chlorides on the Photodestruction of Bisphenol A

Russian Journal of Physical Chemistry A - The effect hydrocarbonates and chlorides, the most common anions in natural and waste waters, on the oxidation of bisphenol A by persulfate activated with...     

Oxidative degradation of phenols in sono-Fenton-like systems upon high-frequency ultrasound irradiation

The kinetics of oxidative degradation of phenol and chlorophenols upon acoustic cavitation in the megahertz range (1.7 MHz) is studied experimentally in model systems, and the involvement of in situ generated reactive oxygen species (ROSs) is demonstrated. The phenols subjected to high frequency ultrasound (HFUS) are ranked in terms of their rate of conversion: 2,4,6-trichlorophenol > 2,4-dichlorophenol ~ 2-chlorophenol > 4-chlorophenol ~ phenol. Oxidative degradation upon HFUS irradiation is most efficient at low concentrations of pollutants, due to the low steady-state concentrations of the in situ generated ROSs. A dramatic increase is observed in the efficiency of oxidation in several sonochemical oxidative systems (HFUS in combination with other chemical oxidative factors). The system with added Fe²⁺ (a sono-Fenton system) derives its efficiency from hydrogen peroxide generated in situ as a result of the recombination of OH radicals. The S₂O₈^2-/Fe²⁺/HFUS system has a synergetic effect on substrate oxidation that is attributed to a radical chain mechanism. In terms of the oxidation rates, degrees of conversion, and specific energy efficiencies of 4-chlorophenol oxidation based on the amount of oxidized substance per unit of expended energy the considered sonochemical oxidative systems form the series HFUS < S₂O₈^2-/HFUS < S₂O₈^2-/Fe²⁺/HFUS.     

Effect of hydrodynamic cavitation on the rate of OH-radical formation in the presence of hydrogen peroxide

It is shown experimentally that hydrogen peroxide is the source of OH-radicals at low-pressure hydrodynamic cavitation. Major preconditions for the intensification of oxidative destruction processes in organic pollutants with an added cavitation stimulus are determined.     

A study of hydrodynamic cavitation generated by low pressure jet devices

Processes proceeding in aqueous solution in a low pressure hydrodynamic cavitation were examined.     

Galvanochemical oxidation of thiocyanates

Method for galvanochemical purification of thiocyanate-containing wastewater, with hydrogen peroxide as oxidizing agent, was suggested. The optimal conditions were found and kinetic parameters of the process were calculated.