In situ grown bacterial cellulose/MoS composites for multi-contaminant wastewater treatment and bacteria inactivation.

For the purpose of developing multifunctional water purification materials capable of degrading organic pollutants while simultaneously inactivating microorganisms from contaminated wastewater streams, we report here a facile and eco-friendly method to immobilize molybdenum disulfide into bacterial cellulose via a one-step in-situ biosynthetic method. The resultant nanocomposite, termed BC/MoS, was shown to possess a photocatalytic activity capable of generating •OH from HO, while also exhibiting photodynamic/photothermal mechanisms, the combination of which exhibits synergistic activity for the degradation of pollutants as well as for bacterial inactivation. In the presence of HO, the BC/MoS nanocomposite exhibited excellent antibacterial efficacy upwards of 99.9999% (6 log units) for the photoinactivation of both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus upon infrared (IR) lamp illumination (100 W, 760 nm ≤ λ ≤ 5000 nm, 15 cm vertical distance; 5 min). Mechanistic studies revealed synergistic pathogen inactivation resulting from the combination of photocatalytically generated •OH and hyperthermia induced by the photothermal conversion of the near-IR light. In addition, the BC/MoS nanocomposite also showed excellent photodegradation activity for common aqueous contaminants in the presence of HO, including malachite green (a textile dye), catechol violet (a phenol) and formaldehyde. Taken together, our findings demonstrate that sustainable materials such as BC/MoS have potential applications in wastewater treatment and microorganism disinfection.