Enhanced Degradation of Micropollutants in a Peracetic Acid–Fe(III) System with Picolinic Acid

Abstract

Activation of peracetic acid (PAA) with iron species is an emerging advanced oxidation process (AOP). This study investigates the use of the chelating agent picolinic acid (PICA) to extend the pH range and enhance the performance of the PAA–Fe­(III) AOP. Compared to the PAA–Fe­(III) system, the PAA–Fe­(III)–PICA system degrades various micropollutants (MPs: methylene blue, naproxen, sulfamethoxazole, carbamazepine, trimethoprim, diclofenac, and bisphenol-A) much more rapidly at higher pH, achieving almost complete removal of parent compounds within 10 min. PAA significantly outperforms the coexistent H2O2 and is the key oxidant for rapid compound degradation. Other chelating agents, EDTA, NTA, citric acid, proline, and nicotinic acid, could not enhance MP degradation in the PAA–Fe­(III) system, while 2,6-pyridinedicarboxylic acid with a structure similar to PICA moderately enhanced MP degradation. Experiments with scavengers (tert-butyl alcohol and methyl phenyl sulfoxide) and a probe compound (benzoic acid) confirmed that high-valent iron species [Fe­(IV) and/or Fe­(V)], rather than radicals, are the major reactive species contributing to MP degradation. The oxidation products of methylene blue, naproxen, and sulfamethoxazole by PAA–Fe­(III)–PICA were characterized and supported the proposed mechanism. This work demonstrates that PICA is an effective complexing ligand to assist the Fenton reaction of PAA by extending the applicable pH range and accelerating the catalytic ability of Fe­(III).

Peracetic Acid Enhances Micropollutant Degradation by Ferrate(VI) through Promotion of Electron Transfer Efficiency

“…Error bars represent standard deviation between parallel experiments. Some data of Figure 2c also appeared in the Supporting Information of ref .…”

“…Ferrate­(VI) [Fe­(VI), HFeO 4 – /FeO 4 2– ] − and peracetic acid [PAA, CH 3 C­(O)­OOH] , are two promising alternative oxidants that are attracting growing interest from environmental engineers and scientists due to their great capacity for pathogen inactivation − and micropollutant abatement. ,− Nonetheless, ferrate­(VI) and PAA both undergo self-decay under environmentally relevant conditions, and their reactivity toward certain contaminants is limited. ,− Thus, various methods for enhancing the oxidation ability of PAA and ferrate­(VI) have been developed in recent years. For example, UV, , Fe­(II), Fe­(III)-picolinic acid-, Co­(II), − Ru­(III), MoS 2 , and Co-based catalysts − have been developed to activate PAA. These PAA-based advanced oxidation processes (AOPs) efficiently degrade various PPCPs, in which organic radicals [e.g., CH 3 C­(O)­O • /CH 3 C­(O)­OO • ] and high-valent metals [e.g., Fe­(IV), Co­(IV)] are proposed as the major reactive species.…”

“…18,28−30 Thus, various methods for enhancing the oxidation ability of PAA and ferrate(VI) have been developed in recent years. For example, UV, 31,32 Fe(II), 33 Fe(III)-picolinic acid-, 34 Co-(II), 35−37 Ru(III), 38 MoS 2 , 39 and Co-based catalysts 40−42 have been developed to activate PAA. These PAA-based advanced oxidation processes (AOPs) efficiently degrade various PPCPs, in which organic radicals [e.g., CH 3 C(O)O • / CH 3 C(O)OO • ] and high-valent metals [e.g., Fe(IV), Co(IV)] are proposed as the major reactive species.…”

Gallic Acid Accelerates the Oxidation Ability of the Peracetic Acid/Fe(III) System for Bisphenol A Removal: Fate of Various Radicals

“…17 For example, chelating agents, such as oxalate, citrate, picolinic acid, and ethylenediaminetetraacetic acid, can increase the concentration of dissolved Fe species. 18,19 Gallic acid (GA), a natural phenolic compound widespread in plants, is ubiquitous in water and wastewater as a component of natural organic matter (NOM). 20 polyphenol can reduce iron to Fe(II).…”

“…Considering the slow spontaneous conversion rate of Fe­(III) back to Fe­(II) ( k = 2.72 ± 0.38 M –1 s –1 ), several strategies have been proposed to accelerate the Fe­(II)/Fe­(III) conversion . For example, chelating agents, such as oxalate, citrate, picolinic acid, and ethylenediaminetetraacetic acid, can increase the concentration of dissolved Fe species. , Gallic acid (GA), a natural phenolic compound widespread in plants, is ubiquitous in water and wastewater as a component of natural organic matter (NOM) . Upon binding of GA to Fe­(III), the polyphenol can reduce iron to Fe­(II) .…”