Antimicrobial and antiviral activity of proton-type zirconium phosphate

Antibacterial and antiviral inorganic materials are attracting increasing attention for their biomedical and environmental applications.This study aimed to examine the antibacterial and antiviral properties of zirconium phosphate powders, Zr(HPO 4 ) 2 H 2 O, Zr(PO 4 )(H 2 PO 4 )2H 2 O, HZr 2 (PO 4 ) 3 , and (H 3 O)Zr 2 (PO 4 ) 3 , and to clarify the role of pH in their activity.Antibacterial activity against Escherichia coli was confirmed in Zr(PO 4 )(H 2 PO 4 )2H 2 O, HZr 2 (PO 4 ) 3 , and (H 3 O)Zr 2 (PO 4 ) 3 powders; high antiviral activity against the bacteriophage Q was detected in Zr(PO 4 )(H 2 PO 4 )2H 2 O and (H 3 O)Zr 2 (PO 4 ) 3 powders, with the antiviral activity of Zr(PO 4 )(H 2 PO 4 )2H 2 O being superior to that of (H 3 O)Zr 2 (PO 4 ) 3 .After immersion in deionized water for 1 d, the pH values of the Zr(PO 4 )(H 2 PO 4 )2H 2 O, HZr 2 (PO 4 ) 3 , and (H 3 O)Zr 2 (PO 4 ) 3 powders reduced to 3.64, 4.41, and 3.99, respectively, becoming lower than that of Zr(HPO 4 ) 2 H 2 O (5.12).The observed effects were attributed to the lower pH caused by the formation of H 3 O + upon contact with water.These results demonstrate that acidity is crucial in the antibacterial and antiviral functions of zirconium phosphate-based materials, providing insights for the design of functional inorganic antimicrobial agents.