Facile fabrication of ceramic tight ultrafiltration membrane with high permeability for rapid separation of dye molecules

Ceramic tight ultrafiltration membrane overcomes the bottleneck of large-scale application in the field of fine separation if the sol–gel route achieves the prepared membrane with a simpler process, narrow pore-size distribution, high water permeance, and structure stability. In this work, a novel ceramic tight ultrafiltration membrane was proposed using the sol–gel method with a high concentration of alumina sol. The prepared ceramic tight ultrafiltration membrane only requires a one-step dip-coating process, saving the fabrication cost while maintaining a high performance. Moreover, the properties and concentration of alumina sol, dip-coating times, membrane microstructure, separation performance, and application stability in acids and alkaline solutions were systematically investigated. The optimized membrane was fabricated by the process of 1.5 mol/L alumina sol, once dip-coating for 8 s, and sintering at 600 °C, resulting in a membrane thickness of 350 nm, high permeability of 150 L/m²·h·bar, an average pore size of 6 nm with narrow pore-size distribution, and high removal rate for dye molecules (98.7 % for Coomassie Brilliant Blue). The long-term filtration of 720 min and different pH solution corrosion demonstrate that the ceramic tight ultrafiltration membrane obtained a superior separation performance and application stability. This study presents a facile method for the fabrication of a high-performance ceramic tight ultrafiltration membrane by a one-step dip-coating process using a high-concentration sol, presenting a practical application potential in dye wastewater treatment and other fine separation fields.