Bacterial Nanocellulose/MoS2 Hybrid Aerogels as Bifunctional Adsorbent/Photocatalyst Membranes for in-Flow Water Decontamination

To address the problems associated with the use of unsupported nanomaterials, in general, and molybdenum disulfide (MoS 2 ), in particular, we report the preparation of self-supported hybrid aerogel membranes that combine the mechanical stability and excellent textural properties of bacterial nanocellulose (BC)-based organic macro/mesoporous scaffolds with the excellent adsorption-cum-photocatalytic properties and high contaminant removal performance of MoS 2 nanostructures. A controlled hydrothermal growth and precise tuning of the synthetic parameters allowed us to obtain BC/MoS 2 -based porous, self-supported, and stable hybrid aerogels with a unique morphology resulting from a molecular precision in the coating of quantum-confined photocatalytic MoS 2 nanostructures (2–4 nm crystallite size) on BC nanofibrils. These BC/MoS 2 samples exhibit high surface area (97–137 m 2 ·g –1 ) and pore volume (0.28–0.36 cm 3 ·g –1 ) and controlled interlayer distances (0.62–1.05 nm) in the MoS 2 nanostructures. Modification of BC with nanostructured MoS 2 led to an enhanced pollutants removal efficiency of the hybrid aerogels both by adsorptive and photocatalytic mechanisms, as indicated by a detailed study using a specifically designed membrane photoreactor containing the developed photoactive/adsorptive BC/MoS 2 hybrid membranes. Most importantly, the prepared BC/MoS 2 aerogel membranes showed high performance in the photoassisted in-flow removal of both organic dye (methylene blue (MB)) molecules (96% removal within 120 min, K obs = 0.0267 min –1 ) and heavy metal ions (88% Cr(VI) removal within 120 min, K obs = 0.0012 min –1 ), separately and/or simultaneously, under UV–visible light illumination as well as excellent recyclability and photostability. Samples with interlayer expanded MoS 2 nanostructures were particularly more efficient in the removal of smaller species (CrO 4 2– ) as compared to larger (MB) dye molecules. The prepared hybrid aerogel membranes show promising behavior for application in in-flow water purification, representing a significant advancement in the use of self-supported aerogel membranes for photocatalytic applications in liquid media.