Highly esthetic, deodorant, and antibacterial tile with natural zeolite set via a blast furnace slag-based geopolymer

Abstract

A natural zeolite-containing esthetic tile was produced by utilizing a geopolymer reaction between a blast furnace slag and sodium silicate solution. Preparation of smooth, flattened, and rigid tiles with maximum flexural strength being 8.0 MPa was achieved by optimizing particle size of the slag (d₅₀ = 5.4 µm) and concentration of the sodium silicate aqueous solution (55 mass %) when dosed rate of the zeolite was fixed to 40 mass % of the whole paste. An amorphous calcium (alumino)silicate hydrate was assumed formed as the cementitious phase after partially dissolving powdery components in the sodium silicate solution. The tiles obtained showed high ability to adsorb NH₃ and H₂S gases, and expressed good antibacterial activity against Escherichia coli. It was also possible to fabricate esthetic, rigid, and deodorant tiles containing the zeolite modified with Cu(II), however, antibacterial activity within 24 h and flexural strength of the tile with the Cu(II)-modified zeolite was slightly less than that without modification. The tiles obtained in this study are considered promising material applicable to interior building products providing us with comfortable lifestyle.