Development of cationic lignin derivatives as sustainable virucidal agents against coronaviruses

The COVID-19 pandemic has highlighted the need to develop effective materials for inactivating pathogens. In this study, the cationization of lignin with glycidyl trimethylammonium chloride (GTMAC) was investigated as a sustainable strategy for producing agents to inactivate the coronavirus. Derivatives with different degrees of substitution (42.5 %, 47.3 %, and 53.5 %) were successfully produced. Physicochemical characterization of the samples demonstrated that the cationization of lignin improves its solubility to values above 50 g/L in both neutral and acidic media and a reduction in its thermal stability at temperatures above 200 °C. The cationization results in a positive charge in the samples, ranging from 24.5 mV to 28.8 mV, however, GTMAC proportions greater than 3.5 relative to lignin in the cationization reaction do not seem to influence the zeta potential. The cationized samples were notably efficient in inhibiting the MHV-3 coronavirus, with inactivation rates of up to 99.999 % within 5 min. These findings show the potential of cationized lignin derivatives as safe and sustainable candidates to deal with future disease outbreaks.