Photolysis and TiO2 Photocatalytic Treatment under UVC/VUV Irradiation for Simultaneous Degradation of Pesticides and Microorganisms

Abstract

<jats:p>Efficiencies of various treatments for UVC photolysis (ultraviolet light-C at 254 nm), VUV photolysis (vacuum ultraviolet light at 254 nm and 185 nm), UVC-assisted titanium dioxide photocatalysis (UVC-TiO2), and VUV-assisted titanium dioxide photocatalysis (VUV-TiO2) were investigated for the degradation of pesticides including pyraclostrobin, boscalid, fludioxonil, and azoxystrobin and inactivation of microorganisms Escherichia coli K12 as a surrogate for E. coli O157:H7 and Saccharomyces cerevisiae in aqueous solutions and on the surface of fresh cut carrots. The degradation efficiencies of VUV were higher than for UVC on pesticides in aqueous solutions. However, there was no significant difference between degradation efficiencies for UVC and UVC-TiO2 treatments, and between VUV and VUV-TiO2 treatments. UVC, VUV, UVC-TiO2, and VUV-TiO2 showed similar inactivation effects against E. coli K12 and S. cerevisiae in aqueous solutions. The combined use of UVC and VUV treatments (combined UV) and combined use of UVC-TiO2 and VUV-TiO2 treatments (combined UV-TiO2) showed higher efficiencies (72–94% removal) for the removal of residual pesticides on fresh cut carrots than bubble water washing (53–73% removal). However, there was no significant difference in removal efficiency between combined UV and combined UV-TiO2 treatments. For E. coli K12 and S. cerevisiae on fresh cut carrots, the combined UV-TiO2 treatment (1.5 log and 1.6 log reduction, respectively) showed slightly higher inactivation effects than combined UV (1.3 log and 1.2 log reduction, respectively). Photolysis and TiO2 photocatalytic treatments under UV irradiation, including VUV as a light source, showed potential for the simultaneous degradation of pesticides and microorganisms as a non-chemical and residue-free technique for surface disinfection of fresh produce.</jats:p>

A review on pesticides degradation by using ultraviolet light treatment in agricultural commodities

“…UV light may be readily paired with ultrasound, ozone, catalysts like titanium dioxide (TiO 2 ), or hydrogen peroxide (H 2 O 2 ) to achieve stimulatory activity and has been intensively investigated for treating wastewater (Abramović et al, 2012). Pesticide residues from fresh-cut carrot surfaces were efficiently removed with the combined UV-TiO 2 (Choi et al, 2020). Indirect photochemical processes (e.g., UV radiation in the presence of oxidants (H 2 O 2 ), catalysts elements such as ferric ion (Fe 3+ ) or H 2 O 2 /ferrous ion (Fe 2+ ), zinc oxide, TiO 2 , cadmium sulfide (Swarnam & Velmurugan, 2013), or treatment emitting more vigorous intensity of light all can enhance degradation rate like pulsed light technology.…”

Photolysis for the Removal and Transformation of Pesticide Residues During Food Processing: A State-of-the-Art Minireview

“…The effect of UV light sources on the degradation of pesticides was further investigated, including VUV, and UVC. Results demonstrated that VUV (185 nm) was more effective than UVC (254 nm) in the degradation of pesticides such as pyraclostrobin, boscalid, fludioxonil, and azoxystrobin under the same reaction condition ( 53 ). It was mainly due to VUV at 185 nm could produce more energetic photons.…”

Heterogeneous Photocatalytic Oxidation and Detoxification of Simulated Agricultural Wastewater Contaminated with Boscalid Fungicide Using g-C3N4 Catalyst

“…Thus, its effective removal from aqueous phases has attracted scientific interest. Among different AOPs, heterogeneous photocatalysis has been evaluated for the removal of boscalid from aqueous matrices using mainly TiO 2 -based and ZnO catalysts [27][28][29][30][31][32]. Despite significant advancements in photocatalysis research in recent years, the effectiveness of this process in the removal of boscalid using alternative photocatalysts remains limited.…”