Bioinspired MXene Membranes with pH-Responsive Channels for High-Performance Water Purification

We present a biomimetic switchable MXene membrane for water treatment inspired by chloride ion transmembrane transport. The MXene membrane was modified with poly(2-diethylaminoethyl methacrylate), resulting in increased hydrophilicity and enlarged channels. The membrane exhibited a permeability of 4.42 × 104 L m–2 h–1 bar–1, surpassing conventional MXene membranes. The membrane also separated Methylene Blue positively charged at pH = 12 and Amido Black 10B negatively charged at pH = 2 with separation efficiency above 98%, thanks to controllable channel size and adjustable electrostatic interactions in response to pH or CO2. This research offers valuable insights into the design of pH-responsive membranes with adjustable selectivity, representing a significant advancement in smart filtration with versatile applications.