Advanced water treatment with antimicrobial silver-lignin nanoparticles sonochemically-grafted on cork granulates in activated carbon packed-bed columns

Cork biomass (C) was grafted with antimicrobial silver phenolated-lignin nanoparticles (AgPLN) using a fast and simple sono-enzymatical process. The AgPLN-functionalised cork (C-AgPLN) exhibited potent antibacterial and antibiofilm properties against the common waterborne pathogens, Escherichia coli and Staphylococcus aureus . Its effects on bacterial cells included alterations in cell morphology and structure, as revealed by electron microscopy (SEM and TEM) and fluorescence microscopy (LIVE/DEAD staining). These effects also included increased oxidative stress (80% and 31% in E. coli and S. aureus , respectively), >99% reduction in viability, a 60% reduction in E. coli biofilm, and a 44% reduction in S. aureus biofilm, as quantified by spectroscopic methods (ROS measurement, XTT metabolic activity test, and crystal violet staining). C-AgPLN also demonstrates anti-quorum sensing properties against both Gram-negative and Gram-positive bacteria, crucial for disrupting bacterial communication, thereby preventing biofilm formation. Further, C-AgPLN was combined with activated carbon (AC) at different proportions (1%, 2%, and 4% w/w) in lab-scale packed-bed columns for the disinfection of water contaminated with E. coli or S. aureus . Columns containing 4% w/w C-AgPLN demonstrated 100% disinfection efficiency after 1 h of operation in recirculation mode (flow rate = 8.6 mL/min), and were reusable for up to 2 and 4 cycles without losing their disinfection capacity. Noteworthy, silver ion (Ag + ) release was not detected in the effluent after 240 h columns operation (ICP-MS detection limit of < 0.07 μg/L), confirming the environmental safety on the novel water-disinfection approach. Given that adsorption is a well-established method for advanced wastewater treatment, these results underscore the potential of nano-enabled AC-packed columns for safely and efficiently controlling the spread of water-associated pathogens. • Cork was sonochemically grafted with Ag-phenolated lignin nanoparticles. • Nano-enabled cork inhibited microbial growth, biofilm formation, and bacterial quorum sensing. • Nano-enabled cork showed higher antimicrobial efficacy against E. coli than S. aureus upon contact. • Water disinfection was achieved by integrating 4% w/w nano-enabled cork into the AC-columns. • Up to 4 cycles of complete water disinfection were achieved with AC/nano-enabled cork columns.