Removal and Inactivation of Virus by Ceramic Water Filters Coated with Lanthanum (III)

Ceramic water filters (CWFs) are widely utilized as a low-cost and effective point-of-use (POU) drinking water treatment technology in developing countries for the removal of pathogenic microorganisms. However, CWFs generally showed low removal efficiency for waterborne virus which poses a high health risk. In this study, we employed a novel lanthanum (La) coating for CWFs to enhance viral removal. Compared to the negligible viral removal of raw CWFs (<0.2 log), CWFs with La coating prepared at 600 degrees C effectively treated similar to 10,000 pore volumes of virus-contaminated water without the detection of any infective virus in the effluent (similar to 5 log removal). Its equivalent treatment volume is expected to surpass the treated volume of a commercial CWF in the whole service lifespan. The characterization of La-coated ceramic, combined with analysis of the extended Derjaguin-Landau-Verwey-Overbeek energy profiles and inactivation kinetic tests, indicated that the enhanced viral removal by La-coated CWFs may be attributed to the increased attachment of virus onto the filter surface due to the reduction of the repulsive energy barrier and the presence of secondary energy minimum, as well as the inactivation nature of La-coated ceramic. These processes minimized the risk of remobilization and release of infective virus from ceramic filters, further confirming by the desorption test. Furthermore, the viral genome and biospectroscopic analysis suggested that both genome damage and protein capsid conformational changes caused the viral inactivation by La-coated ceramic. Our finding showed that La-coated CWFs may represent a promising practical POU treatment solution for viral removal particularly suited for developing countries. The results also provided fundamental insights into the interactions between La species and virions, which may advance the research on La application for water treatment.