Antibacterial activity of silver-carried sodium zirconium phosphate prepared by ion-exchange reaction

Ag+-Na+ exchange equilibrium for carrier (sodium zirconium phosphate) was investigated at 60 degrees C, and the chemical compositions and structure of carrier and silver-carried zirconium phosphate (AgZrP) were investigated by EDX and XRD. The silver valence state and antibacterial activity of AgZrP were also studied. The Ag+ exchange was favorable over the whole Ag+ concentration range. The molecular formulae of carrier [NaZr2(PO4)(3 center dot)H2O] and AgZrP [Ag0.5Na0.5Zr2(PO4)(3 center dot)H2O] have been determined, and the silver of AgZrP was in an ionic state. Both carrier and AgZrP displayed hexagonal crystal structures, but Ag+ exchange resulted in the increase of interplanar spacing and lattice parameter c, and the crystal orientation of AgZrP was affected by the existence of Ag+. Moreover, 100 mg.l(-1) of AgZrP possessed high antibacterial activity and was capable of killing all the Escherichia coli and more than 99.9% of the Staphylococcus aureus within 8.0 h of contact. Furthermore, AgZrP showed a broad-spectrum and long-acting antibacterial activity. (c) 2008 The Ceramic Society of Japan. All rights reserved.