Effect of TiO2 and ZnO Nanoparticles on Photocatalytic and Antimicrobial Activities of Silicate Coatings

Abstract

Silicate paints containing photocatalytically active TiO₂ and ZnO nanoparticles were formulated. The photocatalytic efficiency of coatings was evaluated as a change in absorbance of Orange II solutions. The agar plate method was used for evaluation of antimicrobial properties of coatings. The effectiveness of the coatings was demonstrated using Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus bacteria and Aspergillus niger and Penicillium chrysogenum fungi. A slightly better photocatalytic effect was found in the coatings containing TiO₂ nanoparticles than in those with ZnO. The antimicrobial activity of coatings containing nano-TiO₂ was negligible. The silicate coatings containing 7.5 vol.% of ZnO nanoparticles showed an excellent antimicrobial activity against all tested bacteria and fungi; they partly inhibited also the Penicillium chrysogenum growth. Statistically significant differences between the control coatings and those with ZnO nanoparticles were found using the Rank-sum test.