In situ grown bacterial cellulose/MoS2 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/MoS2, was shown to possess a photocatalytic activity capable of generating •OH from H2O2, 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 H2O2, the BC/MoS2 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/MoS2 nanocomposite also showed excellent photodegradation activity for common aqueous contaminants in the presence of H2O2, including malachite green (a textile dye), catechol violet (a phenol) and formaldehyde. Taken together, our findings demonstrate that sustainable materials such as BC/MoS2 have potential applications in wastewater treatment and microorganism disinfection. [Display omitted] •BC/MoS2 composites were prepared by a one-step in situ biosynthesis method•The satisfying yield of •OH was achieved by the synergistic effect of BC/MoS2.•Pollutants were efficiently removed by BC/MoS2 in the presence of H2O2.•S. aureus and E. coli were rapidly inactivated by 99.9999% with BC/MoS2 + H2O2.