Ecologically benign synthesis of thyme polyphenolic bioactive compounds loaded Poly(vinyl Alcohol)/Sodium Alginate sponges for sustainable point-of-use applications: Characterization and inactivation of waterborne pathogens in water disinfection

Applying environmentally benign sponges in water treatment is considered a promising disinfectant material. Thus, sponge materials based on Poly(vinyl Alcohol)/sodium Alginate (PVA/SA) and loaded with different concentrations (0.5, 1 and 2 mL) of crude thyme extract ( CThE) were prepared. Based on these concentrations of CThE, sponge samples coded with the following codes were obtained (CThE1-loaded PVA/SA sponge, CThE2-loaded PVA/SA sponge, and CThE3-loaded PVA/SA sponge. This study also evaluates the antibacterial efficacy of sponges loaded with crude thyme extract (CThE1, CThE2, and CThE3) inserted in PVA/SA matrix, targeting waterborne pathogens in various water types. Focusing on Salmonella enterica, Klebsiella pneumoniae, Bacillus subtilis, and Enterococcus faecalis, the sponges were tested for their ability to disinfect raw wastewater, tap water, and groundwater. The experiment measured the reduction in bacterial populations over time, assessing the performance across multiple reuses to determine the sponges' sustainability and effectiveness as disinfectants. Results demonstrated that CThE3-loaded PVA/SA sponge could achieve significant bacterial reductions within 4–6 h, with distinct efficacy observed between Gram-negative and Gram-positive bacteria. This study highlights the potential of CThE3-loaded PVA/SA sponge as environmentally friendly, effective alternatives to traditional chemical disinfectants in water treatment applications.