Sieving and Adsorption in Heterophase Alumina Ceramic Membranes for Applications in Water Treatment

This study presents a ceramic membrane (MIX-CM, denoting a mixed phase) fabricated through die casting and sintering of heterophase YS-Al2O3 and α-Al2O3 precursors, yielding a hierarchically mesoporous structure with high porosity (60%) and well-balanced mechanical strength (42 MPa). The MIX-CM demonstrates superior chemical stability (<2% mass loss in acidic/alkaline media) and thermal stability up to 1000 °C. Its unique composite microstructure enables dual-function separation via synergistic sieving and adsorption. Under cross-flow filtration (0.5 bar, 25 °C), MIX-CM achieves high rejection of colloids (>98%), humic acid (>96%), and bovine serum albumin (92%), while exhibiting exceptional adsorption of antibiotics─tetracycline hydrochloride (99.6%) and norfloxacin (95.7%)─and selective removal of heavy metals, with Pb2+ reduced from 492 to 3.4 μg L–1 (below WHO limits). In real surface water treatment, the membrane maintains stable UV254 and turbidity removal at 53% and 78%, respectively. NaClO backwashing achieves 96% flux recovery, while a crushing-reconstruction strategy fully restores severely fouled membranes. The MIX-CM is economically viable, with a production cost of ∼113 USD m–2, markedly lower than commercial ceramic membranes (500–3000 USD m–2). These findings position MIX-CM as a scalable, cost-effective, and multifunctional solution for advanced potable water purification.