Sonochemical synthesis of YSZ nano-sol and ultrathin nanofiltration membranes

The ceramic nanofiltration membranes are widely used in antibiotic desalination due to their high selectivity in separating antibiotics and salts. In this research, a high-flux, highly selective YSZ (yttria-stabilized zirconia) composite nanofiltration membrane was prepared using the sonochemical method. A well-stabilized sol with an average particle size ranging from 1 to 2 nm was obtained through controlled aging and dialysis processes. The doping of yttria effectively inhibited zirconia phase transformation during heat treatment, thereby enhancing membrane integrity and ensuring accurate separation performance. Simultaneously, a 50 nm thick nanofiltration membrane was fabricated on the optimized transition layer, improving its efficient selectivity for antibiotics and salts. At the calcine temperature from 360 to 500 °C, the membrane pore size was precisely tuned to three different MWCOs of 460, 1000, and 2300 Da, with corresponding pure water permeance of 30, 65, and 90 L·m⁻²·h⁻¹·bar⁻¹, respectively. The nanofiltration membrane with a MWCO of 460 Da has retention rates for tetracycline, oxytetracycline, and doxycycline hydrochloride of 96.7 %, 97.6 %, and 99.6 %, respectively, with fluxes of 83.5, 83, and 81 L·m⁻²·h⁻¹. This study shows a highly efficient ceramic nanofiltration membrane with great potential for separating antibiotics and salts.