MnO₂-Modified Bacterial Cellulose as Bio-Based Coatings for Efficient Oil-Water Separation

Oil contamination in aquatic environments remains a persistent challenge, motivating the development of oil-water separation materials that are efficient, low-cost, and environmentally friendly. In this study, manganese dioxide-modified bacterial cellulose (MBC) was developed and evaluated as a bio-based coating for oil-water separation. Bacterial cellulose (BC) was biosynthesized byKomagataeibacter xylinususing either the conventional Hestrin-Schramm (HS) medium or a cost-effective sucrose-rice flour (SRF) medium, followed by in situ MnO₂ functionalization to produce MBC-HS and MBC-SRF, respectively. Both materials were applied as thin coatings on standard filter papers to minimize BC usage. At a low coating density of 0.14 mg·cm^-2, the MBC-coated filter papers achieved separation efficiencies exceeding 98% for palm olein, diesel oil, and motor oil-water mixtures. Surface wettability and interfacial analysis indicate that MBC coatings promote hydrophilic and underwater oleophobic surface characteristics, which favor water permeation while repelling oil droplets. Importantly, MBC derived from SRF-produced BC exhibited separation performance comparable to that of MBC-HS, demonstrating that reduced-cost BC production does not compromise coating functionality. These results highlight the feasibility of combining low-cost BC production with MnO₂ functionalization to fabricate material-efficient bio-based coatings for oil-water separation.