Coating Nanowires with Straw Carbon Enhances Their Bactericidal Performance and Enables Efficient Water Disinfection

Bacterial contamination in water remains a significant public health threat, and it is crucial to develop disinfection methods that are both safe and effective. In this study, we developed straw carbon-coated nanowires (SC/NWs) as an effective bactericidal material for water disinfection. The thermal decomposition of rice straw produced an sp2-structured, amorphous carbon layer with oxygen-containing functional groups and hetero atoms on its surface. The SC coating enhanced the bactericidal performance of Cu(OH)2 NWs by more than 3-log, achieving >6-log inactivation of Escherichia coli at a flux of 2000 L m-2 h-1. The bacteria exposed to SC/NWs suffered extensive membrane disruption and lost cellular integrity. In contrast, the uncoated NWs caused limited damage to the bacteria. Molecular dynamics simulations revealed that the SC coating had strong van der Waals and electrostatic interactions with bacterial membranes, and these attractive forces led to efficient rupture of bacteria during water flow. The SC/NWs were used to disinfect real water samples, including tap water and reclaimed water, with >6-log reductions in bacterial counts during storage. Importantly, no bacterial reactivation was observed after 24 h of storage, which indicated that the SC/NWs caused irreversible membrane damage to the bacteria. This work presents a cost-effective, sustainable solution for developing mechano-bactericidal materials tailored to water disinfection.