Antifungal Properties of High Efficient W/WO3 Electrodes Acting under UV-Vis and Visible Light and Chloride Medium

Abstract

The present work investigates the use of W/WO 3 electrodes prepared by electrochemical anodization applied in the photoelectrocatalytic disinfection of Candida parapsilosis using ultraviolet-visible (UV-Vis) and visible irradiation. The core objective of this work lies in describing a novel approach involving the use of chloride as supporting electrolyte, aiming at achieving a faster inactivation and towards understanding its behavior in water containing high chloride content. The best experimental conditions were found to be at pH 7.0 and 0.1 mol L-1 NaCl when the photoelectrode was biased at 1.5 V (vs. Ag/AgCl) illuminated by both UV-Vis and visible light. It is suggested that charges photogenerated on the electrode surface give rise preferably to HO•, known to be powerful oxidant that causes the total inactivation of the microorganism (1 min of treatment) while engendering around 84% of mineralization of organic matter released from the cell damage following 120 min of treatment.

Photo-assisted electrochemical advanced oxidation processes for the disinfection of aqueous solutions: A review

“…Tungsten trioxide (WO 3 ) is another attractive semiconductor material that has been widely explored due to its relatively low cost and ability to absorb visible light (band gap of 2.5–2.8 eV). This feature extends the photo-catalytic activity of the semiconductor anode into the visible light region leading to utilization of approximately 30% of solar radiation, as opposed to pure TiO 2 ( Juodkazytė et al., 2020 ; Koo et al., 2019 ; Scott-Emuakpor et al., 2012 ; Souza et al., 2017 ). In this context, Souza et al.…”

“…This feature extends the photo-catalytic activity of the semiconductor anode into the visible light region leading to utilization of approximately 30% of solar radiation, as opposed to pure TiO 2 ( Juodkazytė et al., 2020 ; Koo et al., 2019 ; Scott-Emuakpor et al., 2012 ; Souza et al., 2017 ). In this context, Souza et al. (2017) compared the inactivation of C. parapsilosis using Na 2 SO 4 , NaNO 3 and NaCl as electrolytes in photo-electrocatalytic process employing a W/WO 3 photo-anode ( Souza et al., 2017 ).…”

“…Finally, C. parapsilosis present an average size of 7 μm and it is the most frequently isolated agent in hospital settings and responsible for 80% of fungal infections contracted in these facilities. C. parapsilosis affects immunocompromised individuals including those who require prolonged use of intravenous catheter, such as dialysis and cancer patients ( Pires et al., 2016 ; Souza et al, 2017 , 2019 ). The inactivation of C. parapsilosis has been reported in 4.2% of the articles concerning photo-assisted EAOPs ( Fig.…”

“…Ag has therefore been proven to induce effective antibacterial activity, increasing the visible light excitation of TiO 2 , fostering charge transfer events at the solution/semiconductor interphase, facilitating the production of • OH radicals and promoting as a consequence the fast and effective inactivation of microorganisms ( Brugnera et al., 2014 ; Domínguez-Espíndola et al, 2017 , 2019 ; He et al., 2003 ; Rahmawati et al., 2011 ). Ag also alters the transport system within the cell membrane resulting in catastrophic permeability, osmoregulation, electron transport and respiration events that eventually lead to cell death ( Mafa et al., 2020 ).…”

“…(2017) and Domínguez-Espíndola et al. (2019) also reported that Ag acts as photo-generated electron-trapping sites that prevent the recombination of photo-generated e − /h + pairs; thus increasing the bacterial inactivation rate ( Domínguez-Espíndola et al, 2017 , 2019 ). However, according to Pires et al.…”