Fabrication of natural clay-based ceramic membranes with Mg-La oxides coating for enhanced water treatment

This study presents the development of a novel magnesium-lanthanum mixed metal oxide (Mg-La MMO) coating on porous clay ceramic membrane aimed at enhancing wastewater purification. The membranes were prepared via dip coating with varying Mg to La molar ratios of 2:1, 1:1, and 1:2. The efficiency of these membranes in removing phosphate (PO43-), oil, and humic acid (HA) from aqueous solutions was thoroughly evaluated. Comprehensive characterization techniques, including SEM, FTIR, BET, XPS, XRD, and contact angle, were employed to analyze the membrane's morphological, chemical, and surface properties. The Mg-La coated membranes exhibited superior hydrophilicity and oleophobicity compared to uncoated membrane, resulting in enhanced water permeability and oil rejection capabilities. Among them, the M1L2 membrane (Mg-La 1:2 molar ratio) demonstrated the highest performance. The M1L2 membrane achieved a pure water permeance of 120 LMH at 1 bar leading to the formation of a tight ultrafiltration membrane. In terms of PO4 3- rejection, the M1L2 membrane demonstrated almost complete removal for 40 min of filtration, significantly higher than the 55.5 % removal for the uncoated support. For oil separation, the M1L2 membrane maintained high rejection: 88.7 % at 100 ppm, 97.6 % at 500 ppm, and 98.4 % at 1000 ppm. The antifouling performance was also noteworthy, with permeance recovery ratios of 82.0 % and 75.6 % for the M1L2 membrane across two HA filtration cycles, compared to 73.6 % and 66.3 % for the uncoated support. This study demonstrates a promising approach to enhancing ceramic membrane functionality through Mg-La MMO coating, offering a viable solution for efficient and sustainable wastewater management.