Antibacterial activity of silver-loaded "green Zeolites"

"Green Zeolites" were prepared, without the use of organic structure-directing agents (OSDAs), by the seed-assisted method and were loaded with silver by a simple ion-exchange procedure. The silver-loaded zeolites were characterized by XRD, transmission electron microscopy and inductively coupled plasma atomic emission spectroscopy, which reveals that the ion-exchange procedure does not affect the structure of the zeolites and the presence of silver cations inside the aluminosilicate matrix. Two types of zeolites presenting different pore arrangements were studied: the beta-type with three-dimensionally interconnected pores and the MTW-type with one-dimensionally interconnected pores. Their activity against E. coli was studied and compared with a commercial zeolite. The influence of the arrangement of the pore channels and the amount of silver loaded were studied. Comparison with the commercial product shows that a smaller amount of silver inside the zeolite is necessary to achieve a similar antibacterial performance within one hour. Silver-loaded green zeolites (beta and MTW-type) were synthesized by using the seed-assisted method followed by an ion-exchange procedure. Their ability to kill E. coli bacteria over a short period through release of silver cations to the cells was demonstrated and compared to that of the commercial zeolite.