by Biao Dong, Sama Belkhair, Dr. Zaarour, Leanne Fisher, Joanna Verran, Lubomira Tosheva, Richard Retoux, Jean-Pierre Gilson and svetlana mintova
Nanoscale, 2014, Accepted Manuscript
The preparation of pure zeolite nanocrystals (EMT-type framework) and their silver ion-exchanged (Ag+-EMT) and reduced silver (Ag0-EMT) forms is reported. The template-free zeolite nanocrystals are stabilized in water suspensions and used directly for silver ion-exchange and subsequent chemical reduction under microwave irradiation. The high porosity, low Si/Al ratio, high concentration of sodium and ultrasmall crystal size of the EMT-type zeolite permitted the introduction of high amount of silver using short ion-exchange times in the range 2-6 h. The killing efficacy of pure EMT, Ag+-EMT and Ag0-EMT against Escherichia Coli was studied semi-quantitatively. Antibacterial activity increased with increasing Ag content for both type samples (Ag+-EMT and Ag0-EMT). The Ag0-EMT samples show slightly enhanced antimicrobial efficacy compared to that of Ag+-EMT, however, the differences are not substantial and the preparation of Ag nanoparticles is not viable considering the complexity of preparation steps.