Bi-based photocatalysts for bacterial inactivation in water: Inactivation mechanisms, challenges, and strategies to improve the photocatalytic activity

Bi-based photocatalysts have been considered suitable materials for water disinfection under natural solar light due to their outstanding optical and electronic properties. However, until now, there are not extensive reviews about the development of Bi-based materials and their application in bacterial inactivation in aqueous solutions. For this reason, this work has focused on summarizing the state of the art related to the inactivation of Gram-and Gram + pathogenic bacteria under visible light irradiation using different Bi-based micro and nano structures. In this sense, the photocatalytic bacterial inactivation mechanisms are analyzed, considering several modifications. The factors that can affect the photocatalytic performance of these materials in real conditions and at a large scale (e.g., water characteristics, pH, light intensity, photocatalyst dosage, and bacteria level) have been studied. Furthermore, current alternatives for improving the photocatalytic antibacterial activity and reuse of Bi-based materials (e.g., surface engineering, crystal facet engineering, doping, noble metal coupling, heterojunctions, Z-scheme junctions, coupling with graphene derivatives, magnetic composites, immobilization) have been explored. According to several reports, inactivation rate values higher than 90% can be achieved by using the modified Bi-based micro/nano structures, which become them excellent candidates for photocatalytic water disinfection. However, these innovative photocatalytic materials bring a variety of future difficulties and opportunities in water disinfection.

Automated summary

Bi-based photocatalysts have been shown to be effective for water disinfection under natural solar light. This study summarizes the latest research on using different Bi-based micro and nano structures for photocatalytic inactivation of pathogenic bacteria under visible light irradiation. The study analyzes the mechanisms of photocatalytic bacterial inactivation and explores various modifications to improve their performance. Factors that affect the photocatalytic activity of these materials in real conditions and at a large scale have been studied. The study also explores current alternatives for enhancing antibacterial activity and reusing Bi-based materials.