Ultra-thin titanium carbide (MXene) sheet membranes for high-efficient oil/water emulsions separation

Oily wastewater from oil spill and industrial water discharge poses danger to human body and the environment. Fouling is the bottleneck of membrane for oily wastewater separation. Here, an ultra-thin 2D titanium carbide MXene membrane (about 30 nm) supported on porous polyethersulfone (PES) as substrate with high performance and excellent stability for oil-in-water emulsion separation is designed. The high antifouling resistance, promising oil/water separation and excellent recyclability of the MXene membranes are originated from their inherent hydrophilicity, low adhesion of oil droplets as well as the regular stacking of the 2D lamellar structure. Molecular Dynamics simulations further confirm that the hydrophilic MXene membranes with low oil adhensive force. Moreover, for salt-containing oily wastewater, the MXene membranes exhibit even higher oil rejection with low compromised water permeance due to the reduced d-spacing because of ion intercalation. Such ultrathin MXene 2D membranes with outstanding recyclability and high separation performance pave an avenue for a broad oil/water separation.