Oxidation Efficiencies of Potassium Persulfate and Hydrogen Peroxide in Pressurized Hot Water with and without Preheating

Abstract

Potassium persulfate was compared with hydrogen peroxide as oxidant in pressurized hot water. Oxidant (in excess) and organic model pollutants (phenol, 2,3-dichlorophenol, and m-cresol, c ) 0.3-0.5 mM each) were introduced to the reaction capillary with and without preheating. Reaction time was 4-57 s, temperature 80-400 °C, and pressure 220-310 bar. Without preheating, potassium persulfate was clearly more efficient than hydrogen peroxide in oxidizing the model compounds: for example, with potassium persulfate, removal percentages close to 100 were obtained in 55 s at 110 °C, whereas with hydrogen peroxide the required temperature to obtain similar results in any reaction time was nearly 300 °C. Total organic carbon was removed more effectively by potassium persulfate under mild conditions. Overall, oxidation efficiencies were decreased when capillaries were preheated, especially with potassium persulfate as oxidant. Corrosion, measured as Ni concentration of the effluent, was more severe with potassium persulfate than hydrogen peroxide.

Oxidation of 4-Chloro-3-methylphenol in Pressurized Hot Water/Supercritical Water with Potassium Persulfate as Oxidant

“…Excellent conversions were obtained at temperatures clearly under 200 °C. The good oxidation power of potassium persulfate was observed in our previous studies, too (26,27). As can be seen, the conversion increased with temperature and contact time (Figures 2 and 3).…”

Effects of Combined and Sequential Addition of Dual Oxidants (H2O2/S2O82-) on the Aqueous Carbofuran Photodegradation

“…The reactor was equipped with eight phosphor-coated low-pressure mercury lamps, emitting 253.7 nm monochromatic UV at a light intensity of 1.5 × 10 -6 Einstein L -1 s -1 . Samples after UV exposure were mixed with an excess of sodium nitride (10) to quench the radicals before the quantification of the probe compound, intermediates, and total organic carbon (TOC).…”

Degradation of iopromide by combined UV irradiation and peroxydisulfate

“…Theoretically, sulfate ion can be regenerated electrolytically to peroxydisulfate for reuse in water as shown by Balazs et al [14]. Since peroxydisulfate will start reacting exothermally only at 100 • C [15], it is not recommended for use in conventional water purification processes. The potential use of photo-activated peroxydisulfate at ambient temperature is of interest and has been investigated as a treatment method for the endocrine disruptor chemical, butylated hydroxyanisole (BHA) [16].…”