The Pathway towards Photoelectrocatalytic Water Disinfection: Review and Prospects of a Powerful Sustainable Tool

Abstract

Photoelectrocatalysis is a hybrid photon/electron-driven process that benefits from the synergistic effects of both processes to enhance and stabilize the generation of disinfecting oxidants. Photoelectrocatalysis is an easy to operate technology that can be scaled-up or scaled-down for various water treatment applications as low-cost decentralized systems. This review article describes the fundamentals of photoelectrocatalysis, applied to water disinfection to ensure access to clean water for all as a sustainable development goal. Advances in reactor engineering design that integrate light-delivery and electrochemical system requirements are presented, with a description of photo-electrode material advances, including doping, nano-decoration, and nanostructure control. Disinfection and cell inactivation are described using different model microorganisms such as E. coli, Mycobacteria, Legionella, etc., as well the fungus Candida parapsilosis, with relevant figures of merit. The key advances in the elucidation of bacterial inactivation mechanisms by photoelectrocatalytic treatments are presented and knowledge gaps identified. Finally, prospects and further research needs are outlined, to define the pathway towards the future of photoelectrocatalytic disinfection technologies.

Bismuth Oxyhalide-Based Materials (BiOX: X = Cl, Br, I) and Their Application in Photoelectrocatalytic Degradation of Organic Pollutants in Water: A Review

“…In this way, the composite achieves a better charge separation and thus a higher degradation efficiency compared to individual materials. This is because, there are more holes able to oxidize the contaminant molecules or produce hydroxyl radicals (strong oxidants) when they react with the water, and superoxide radicals when the electrons on the cathode surface reduce the oxygen in the solution (Younis et al, 2020;Garcia-Segura et al, 2021). Definitely, Table 1 summarizes the most recent applications of BiOX-based photoanodes prepared by various synthesis methods, intended for the degradation of organic pollutants in aqueous media.…”

The Surge of Metal–Organic-Framework (MOFs)-Based Electrodes as Key Elements in Electrochemically Driven Processes for the Environment

“…The catalytic response of semiconductor materials exposed to light irradiation was first described in the seminal work of Fujishima and Honda in 1972. The photocatalytic effect is observed when a semiconductor is irradiated with photons of energy superior to the characteristic bandgap energy (E g ) of the material [86,87]. The light-semiconductor interaction induces the photoexcitation of an electron from the completely filled valance band (VB) of the semiconductor to the empty conduction band (CB).…”

Overcoming barriers for nitrate electrochemical reduction: By-passing water hardness

“…Electrochemical processes can achieve effective removal of organics through electrochemical advanced oxidation processes (dos Santos et al, 2021;Moreira et al, 2017;Villanueva-Rodríguez et al, 2012), inactivation of pathogens through electrodisinfection (Garcia-Segura et al, 2021;Martínez-Huitle and Brillas, 2021), and even abatement of oxyanions such as nitrate by electrochemical advanced reduction processes (Sergi Garcia-Segura et al, 2018;van Langevelde et al, 2021).…”