Voltage-Gated Ions Sieving through 2D MXene Ti3C2Tx Membranes

We report a nanochanneled Ti 3 C 2 T x MXene membrane that enables an efficient controlled rejection/permeation of inorganic ions and organic dye molecules under applied electrical potential. When a negative electrical potential (−0.6 V) is applied to the Ti 3 C 2 T x MXene membrane under only osmotic pressure, the rejection of inorganic salt (NaCl or MgSO 4 ) through the membrane is enhanced. In contrast, applying a positive potential inhibits the rejection through electrostatic repulsion between charged MXene layers and inorganic cations in solution. The rejection rates of Ti 3 C 2 T x membranes are also tested in a flow-through system. MXene membranes as thin as 100 nm show a high rejection rate above 97.9 ± 1.0% for methylene blue dye molecules. Similar to inorganic salts, application of negative or positive voltages increases and decreases, respectively, the transport of molecules through Ti 3 C 2 T x membranes. The voltage gated rejection through electronically conductive membranes is demonstrated as a promising alternative to improve rejection of inorganic salts and organic molecules.