The new concept of antimicrobial catalysis: disinfection of ships ballast water

Abstract

The present paper introduces the new concept of antimicrobial catalysis towards the disinfection/treatment of ships ballast water (SBW), which is considered as a priority issue for the shipping industry. Taking into account the well-known antimicrobial properties of ionic silver (Ag+), five silver supported catalysts (Ag/γ-Al2O3) with various loadings (0.05 wt%, 0.1 wt%, 0.2 wt%, 0.5 wt%, and 1 wt%) were prepared and examined for the antimicrobial treatment of ships ballast water. The bactericidal activity of the aforementioned catalysts was investigated towards the inhibition of E. coli and E. faecalis bacteria. Catalytic experiments were conducted in a three-phase continuous flow stirred tank reactor, used in a semibatch mode. It was found that using the catalyst with the lowest metal loading, the inhibition of E. coli reached 95.8% after 90 min of treatment of an E. coli bacteria containing solution, while the inhibition obtained for E. faecalis was 76.2% after 60 min of treatment of an E. faecalis bacterial solution. The results of the present work indicate that the prepared monometallic catalysts exert their antimicrobial activity within a short period of time, revealing, for the first time ever, that the field of antimicrobial heterogeneous catalysis using deposited ionic silver on a solid support may prove decisive for the disinfection of SBW.