Hydrogen peroxide and persulfate activation using UVA-UVB radiation: Degradation of estrogenic compounds and application in sewage treatment plant waters

Abstract

In the present work, the degradation of three estrogens (17β-estradiol (E2), estrone (E1) and 17α-ethinylestradiol (EE2)) was investigated under photoactivation of hydrogen peroxide and persulfate. Lab-scale irradiation experiments showed that both UVA and UVB radiations are able to photoactivate the oxidant precursors, although UVB is more efficient to generate radicals and therefore to degrade the targets. The efficiency of both oxidant precursors was investigated showing higher efficiency in the system with persulfate. The pseudo-first order degradation rate constants and the second order rate constants between the hydroxyl or the sulfate radicals and estrogens were measured. In order to evaluate the process efficiency in real treatment conditions, the degradation of the estrogens spiked into sewage treatment plant effluent was studied. Measurements of second order rate constants between the radical and the effluent organic matter by laser flash photolysis allowed to understand the involved quenching mechanisms. A Yeast Estrogen Screen (YES) assay was used to follow the decrease in estrogenic activity during the estrogen degradation. This assay permitted to ensure that the studied processes are not only able to degrade the estrogens but also to remove their estrogenic activity.

Pilot-scale assessment of the viability of UVA radiation for H2O2 or S2O82− activation in advanced oxidation processes

“…ranges from 2.2 ± 0.2 × 10 -5 to 3.0 ± 0.2 × 10 -4 cm 2 mJ -1 under UVA and from 9.4 ± 0.4 × 10 -4 to 1.1 ± 0.1 × 10 In the UVA/H 2 O 2 process, goes from 2.2 ± 0.2 × 10 -5 to 3.5 ± 0.3 × 10 -5 cm 2 mJ -1 with 46 to 64% of the degradation achieved by oxidation. These close results are attributed to similar photolysis constants of the estrogens (Table 7) and similar second order rate constants (from 1.8 to 2.9 × 10 10 M -1 s -1 ) between HO • and the estrogens [9]. When using S 2 O 8…”

“…Then, another alternative is the use of solar light as a UV source. Incident solar radiation on earth is a free and renewable energy, composed of 95% of UVA and 5% of UVB and it was previously reported in the literature that UVA radiation is able to photolyse H 2 O 2 and S 2 O 8 2- [9,10]. Fernandes et al [11] also recently demonstrated that natural solar radiation is efficient in activating these oxidant precursors.…”

Photooxidation-Initiated Aqueous-Phase Formation of Organic Peroxides: Delving into Formation Mechanisms

“…Given the fragility of the O–O bond, , we examined the effects of the wavelength of UV light used in irradiation. An aqueous solution of 7-OE and H 2 O 2 was oxidized under three wavelengths: UVC, UVB, and UVA .…”

Per-/Poly-fluoroalkyl Substances (PFASs) Treatment and Mechanistic Insights: Photo-catalyst and Photo-Electro-catalyst Materials Application

“…Hence a new class of metal-based nanoadsorbents/heterogeneous catalysts with a better redox activity, photocatalytic nature in the visible band (400-700 nm), and economically feasible materials (e.g., Fe, Mn, Al) need to be studied as near-futuristic research and innovation technologies. Recently, a few research groups developed a new approach of metal ion activated external oxidants (Peroxymonosulfate: PMS, Persulfate: PS) in generating reactive radical species (i.e., sulfate radicals) for remediating various organic contaminants (e.g., estrogenic compounds) [53,54]. A recent article on reviewing the light-induced advanced oxidation processes (AOPs) as PFAS remediation methods are detailed elsewhere [32], whereas the present work focuses on light-induced, electrochemical supported [electro-oxidation] AOPs in addition to the electro-kinetic/coagulation-sorption.…”