Improved disinfection performance towards human adenoviruses using an efficient metal-free heterojunction in a vis-LED photocatalytic membrane reactor: Operation analysis and optimization

Waterborne human viruses, with ubiquitous prevalence in aquatic environments, extremely low infectious doses, and high resistance to common disinfection processes, pose a substantial threat to human health. Herein, for the first time, a photocatalytic membrane reactor (PMR) driven by visible light emitting diodes (Vis-LEDs) was applied for effective water disinfection of human adenoviruses. The photocatalyst used in the PMR was selected to be a metal-free heterojunction (named as CNO) with the advantages of visible-light-response, efficient virucidal effects, green properties and easy recovery via microfiltration. The disinfection performance of the Vis-LED PMR towards human adenoviruses was improved by adjusting operation with response surface methodology (RSM). Based on twenty sets of operating data, a semi-empirical model was established with a high accuracy of R 2  = 0.9622 for predicting the final adenovirus inactivation after 300-min operation. The optimal operating solution was found to be 5.00-log MPN/mL, 320.30 mg/L and 502.65 min for initial virus concentration (IVC), photocatalyst loading (PL) and hydraulic retention time (HRT), respectively. Under the optimized operation, all human adenoviruses were completely inactivated without regrowth, accompanied by severe damage to capsids, within 600 min in the Vis-LED PMR. In addition, the CNO photocatalyst could be retained inside the reactor via low-energy microfiltration with excellent recovery (99.9 wt%) but without obvious chemical or structural changes. Our work can offer a simple, effective, economical and eco-friendly water disinfection device against resistant pathogenic microbes, with controllable efficiency by facilely varying operating solutions.