Thermal Activation of Peracetic Acid in Aquatic Solution: The Mechanism and Application to Degrade Sulfamethoxazole

Abstract

Chemical oxidation using peracetic acid (PAA) can be enhanced by activation with the formation of reactive species such as organic radicals (R−O • ) and HO • . Thermal activation is an alternative way for PAA activation, which was first applied to degrade micropollutants in this study. PAA is easily decomposed by heat via both radical and nonradical pathways. Our experimental results suggest that a series of reactive species including R−O • , HO • , and 1 O 2 can be produced through the thermal decomposition of PAA. Sulfamethoxazole (SMX), a typical sulfa drug, can be effectively removed by the thermoactivated PAA process under conditions of neutral pH. R−O • including CH 3 C(O)O • and CH 3 C(O)OO • has been shown to play a primary role in the degradation of SMX followed by direct PAA oxidation in the thermoactivated PAA process. Both higher temperature (60 °C) and higher PAA dose benefit SMX degradation, while coexisting H 2 O 2 inhibits SMX degradation in the thermoactivated PAA process. With a variation of solution pH, conditions near a neutral value show the best performance of this process in SMX degradation. Based on the identified intermediates, transformation of SMX was proposed to undergo oxidation of the amine group and oxidative coupling reactions. This study definitively illustrates the PAA decomposition pathways at high temperature in aquatic solution and addresses the possibility of the thermoactivated PAA process for contaminant destruction, demonstrating this process to be a feasible advanced oxidation process.

Novel Nonradical Oxidation of Sulfonamide Antibiotics with Co(II)-Doped g-C3N4-Activated Peracetic Acid: Role of High-Valent Cobalt–Oxo Species

“…With the reaction progressing, further attacks took place at the aniline ring via oxygen transfer reaction, and it subsequently resulted in the formation of TP-201. Notably, some dimeric products were believed as the degradation product of SMX by R−O • through the coupling reaction between hydroxyl-SMX and N-centered radicals, 5,8 and these products were readily detected in the thermal/PAA process but could not be identified in the PAA/CCN4 process, further verifying the insignificant role of R−O • during the PAA/CCN4 oxidation.…”

“…This conclusion can be further favored by its remarkable oxidizing capacity of carbamazepine (CBZ), which was contradictory to the attacking behavior R–O • , given that CBZ is inert to R–O • (Figure S6). ,, …”

“…This conclusion can be further favored by its remarkable oxidizing capacity of carbamazepine (CBZ), which was contradictory to the attacking behavior R−O • , given that CBZ is inert to R−O • (Figure S6). 5,6,24 Nonradical Oxidation. The TEMP-trapping experiment was conducted to ascertain whether 1 O 2 can be produced.…”

“…Fenton-like processes based on the activation of peracetic acid (PAA) have recently received tremendous attention as potential remediation technologies for the decontamination of refractory organic pollutants. − Among various activation strategies (e.g., heat, UV, , and low-valent transition-metal ions − ), Co­(II) exerts an outstanding catalytic activity. However, these types of homogeneous catalysts are suffered from the drawbacks of harsh reaction environments, metal-ion leaching, and difficulty in separation/recycling. − In addition, concerns have also been raised about the toxicity of cobalt ion during water remediation, which could pose potential health risk to human and other organisms .…”

New Insights into the Activation of Peracetic Acid by Co(II): Role of Co(II)-Peracetic Acid Complex as the Dominant Intermediate Oxidant

“…PAA could be considered as a derivative of H 2 O 2 , in which one H atom is replaced by a -(O)­CCH 3 group. Although PAA has a high redox potential (1.06–1.96 V), PAA alone is not efficient for the oxidation of refractory contaminants, and thus, activation is required. , Several approaches including UV irradiation, transition metals, and heat have been demonstrated effective for PAA activation. In particular, Co­(II) exhibits satisfactory catalytic activity even at a low dosage. , The Co­(II)/PAA process is reported to be selective toward some microorganic pollutants such as sulfamethoxazole, furosemide, and trichlorophenol .…”