N-Schorl TiO2 nanocomposite for visible-light photocatalysis deactivation yeast exemplified by Candida albicans

Candida albicans (C. albicans) presents serious public health risks because of its presence in water matrices and its known resistance to various antifungal drugs. Although microbial photo-deactivation has gained intensive attention over decades, the existing deactivation process is still under debate. Finding a solution for effective fungal photo-deactivation remains a challenge and necessary task. We have demonstrated that the as-synthesized nitrogen-schorl co-modified TiO2 (N-Schorl-TiO2) photocatalytic nanocomposite is highly effective in deactivating pathogenic C. albicans under visible-light irradiation. Compared to the deactivation time with the other studies, N-Schorl-TiO2 is 1.5–6 times faster. The created electric field via schorl on the N-TiO2 provides the following vital features: prolonging the process of the electron-hole pair recombination on the surface of photocatalyst, improving the photo-deactivation performance of N-Schorl-TiO2, and preventing the nanoparticles aggregation. Ultimately, N-Schorl-TiO2 enables the 2-log-decrease photocatalytic deactivation process on C. albicans with gaining abundant •OH and 1O2 in only 6 h. Core evidences of schorl modification on the N-TiO2, •OH production and morphology information using ESR, XPS, XRD, HRTEM, and SEM are provided. This is the first work that comprehensively evaluates the critical factors, i.e., photocatalyst concentration, initial yeast concentration, and light irradiance, for C. albicans photo-deactivation. Moreover, we have found that the deactivation kinetics is appropriately described by a newly developed Light-responsive modified Hom's (LMH) model, demonstrating a good prediction of photocatalyst performance on C. albicans deactivation. Overall, this study highlights a highly efficient approach for yeast or fungi pathogen deactivation using visible-light responsive N-Schorl-TiO2, and it can serve as an essential reference for applying visible-light-responsive photocatalyst in anti-fungal treatments.