Novel application of Fe-Mg-Mt-SS activated persulfate for the disinfection of Escherichia coli in water: Performance and mechanism

Abstract

New technology is required for the effective disinfection of pathogenic bacteria in water. A novel type of activator material (Fe-Mg-Mt-SS) was prepared using bimetallic iron-magnesium (Fe-Mg), montmorillonite (Mt), and sewage sludge carbon (SS) and applied it for disinfection. The specific surface area of Fe-Mg-Mt-SS was 115.72 m2/g, and the spatial structure of Fe-Mg-Mt-SS was orderly and layered. Mt played a role in frame support, and Fe-Mg was integrated into the structure in an orderly manner. Fe-Mg-Mt-SS effectively activated persulfate (PS) to disinfect Escherichia coli (E. coli) in water, with a disinfection rate of 7.00 lg of E. coli within 80 min in the PS/Fe-Mg-Mt-SS system, and the high disinfection rate was stable under different pH and elevated temperatures. Fe-Mg-Mt-SS showed broad spectrum disinfectant efficiency against other bacteria (Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus subtilis). Fe-Mg-Mt-SS activated PS killed E. coli mainly by producing hydroxyl and oxygen radicals, which damaged the E. coli cell membrane. Bimetallic activation with Fe and Mg synergistically activated PS, graphitised SS had more orderly spatial and laminar structures, and Mt improved the thermal stability and layer spacing of Fe-Mg-Mt-SS, which facilitated better metal insertion and improved its activation properties. The preparation of Fe-Mg-Mt-SS and activation of PS provide a new technology for the disinfection of pathogenic bacteria in water.