Ultralight, mechanically robust, water stable MXene–chitosan aerogels for concurrent dye adsorption and antibacterial filtration at low MXene loading

Ultralight, water-stable adsorbents that deliver both dye removal and sustained antibacterial activity are increasingly sought for decentralized water purification. We report a scalable strategy to integrate Ti₃C₂Tₓ MXene with chitosan (CS) into three-dimensional, compressible aerogels (MCA) that couple high adsorption capacity for the anionic azo dyes methyl orange (MO) and Eriochrome Black T (EBT) with strong, reusable suppression of Escherichia coli and Enterococcus faecalis. At an optimal 12 wt% MXene loading (MCA@12), the aerogel exhibited ultralow density (~0.027 g cm⁻³), high elastic recoverability, seven-fold higher BET surface area than CS-only aerogels, and remarkable long-term aqueous stability (≥2160 h). In batch adsorption, MCA@12 achieved a maximum MO capacity of ~523 mg g⁻¹ (Langmuir fit) and retained ~89% capacity over five cycles. Adsorption was faster under mildly acidic conditions due to enhanced protonation of chitosan’s amine groups and electrostatic attraction with anionic dyes. Under continuous-flow filtration, MCA@12 sustained ~92% bacterial clearance and ~93% MO removal, maintaining performance over six reuse cycles. These findings outline a clear design strategy where low MXene content embedded in a chitosan-rich, biodegradable matrix yields a mechanically robust, water-stable, and multifunctional aerogel—a cost-effective and modular platform for practical water purification.