Laponite Nanosheets Modified Polyethersulfone Membranes with Enhanced High-pressure Resistance for Stable Separation

Many high-performance ultrafiltration membranes have been developed to address pollutant removal in complex water environments. However, the permeability-selectivity trade-off and inherent instability issues remain unresolved. In this study, a dense ultrafiltration membrane modified with laponite nanosheets is fabricated for selective separation and purification. The laponite nanosheets exhibit excellent compatibility with the polyethersulfone matrix, owing to their well-defined dimensions, distinctive physicochemical properties, and the dispersing role of polyvinylpyrrolidone, resulting in a membrane with synergistic performance characteristics. The modified membrane demonstrates a high pure water flux (106.3 L m -2 h -1 ), near-complete rejection of Congo red (>99.9 %), and high rejection rate of Methylene blue (89.8 %). Within a wider pressure range (0.1-3.0 MPa), the permeation flux maintains a linear relationship with increasing pressure, while the rejection rate for Congo red is nearly 100 %. In addition, under a high pressure of 2.0 MPa, laponite nanosheet-modified polyethersulfone membrane exhibits high stability and good separation performance under high-pressure conditions. These attributes significantly enhance separation precision and operational reliability in dye wastewater systems, indicating strong potential for practical application.