Voltage-Gated Pillararene-Intercalated MXene membranes for adjusting water purification

Abstract

The adaptive membrane, capable of intelligently adjusting its permeability and selectivity based on environmental conditions, is critically important in separation technology. Here, MXene nanosheets were anchored with carboxyl pillararenes (CP6), effectively crosslinking the hybrid MXene nanosheets and further assembling them into a regular two-dimensional (2D) channel membrane using a vacuum-assisted approach. The rigid CP6 structure creates a stable channel, suppressing material aggregation and enhancing water permeance to 119 ± 6.7 L m^-2h⁻¹ bar⁻¹. This membrane also controls the repulsion of organic dye molecules with an applied voltage. When the membrane operates as a cathode, the retention rate of methyl green reaches 98 %. Conversely, when it functions as an anode, the retention rate drops to 0 %. The change of the interlayer spacing within membrane is responsible for adjusting water purification toward voltage stimuli. These studies offer a novel approach to creating voltage-gated smart membranes and provides fresh perspectives on water treatment solutions.