Lanthanum-modified fly ash ceramsite for sustainable waterborne virus inactivation: Performance and mechanism

Waterborne viruses pose a significant threat to public health, particularly in reclaimed water systems. Conventional disinfection technologies often exhibit limited viral removal efficiency, especially under varying water quality conditions, and may contribute to the formation of disinfection by-products. In this study, a fly ash-based ceramsite modified with lanthanum (CL-600) was synthesized and evaluated for its antiviral efficacy against bacteriophage PhiX174. CL-600 demonstrated a maximum removal efficiency of 5.56-log₁₀ for PhiX174, significantly surpassing the 0.58-log₁₀ of unmodified ceramsite. This removal was dosage-dependent while overcoming the agglomeration issues common to traditional materials. Moreover, CL-600 maintained high inactivation across pH 5-9, even under high viral loads or natural organic matter. The primary inactivation mechanism of CL-600 was identified as adsorption-enabled contact inactivation at surface La sites. Structural analysis revealed damage to the capsid proteins, including proteins A, F, H and G. Furthermore, DNA exposure led to damage to nine pairs of functional genes, with the most significant damage corresponded to gene H. Collectively, these structural damages disrupted viral attachment, injection, and replication functionalities and leading to reduced infectivity. This study demonstrated that CL-600 provides a high efficiency in waterborne virus inactivation, highlighting the potential of lanthanum-based materials for sustainable water safety management.