Geopolymers functionalised by antibacterial zeolite against biocorrosion

Abstract

<p> <span>Aluminosilicate geopolymer with remarkable chemical and biological resistance is a promising material solution to the persistent challenge of microbial induced concrete corrosion (MICC) in sewers. In this work, novel Sor-zeolite, assembled by using microporous 13X zeolite as a host of antimicrobial ion sorbate, is incorporated into fly ash-slag geopolymer to form bio-resistant materials with long-lasting efficacy and densified microstructure. The inclusion of pure zeolite and Sor-zeolite increase the strength and refine the pore structure of geopolymer pastes owing to the seeding nuclei effects during the geopolymerisation process. The enhanced dissolution of FA and slag by the seeding effects of pure zeolite and Sor-zeolite, accelerates and enriches the precipitation of geopolymeric gels, mainly a mixture of K-A-S-H and C-A-S-H (abbreviated as K-(C)-A-S-H). The Sor-zeolite-functionalised geopolymer possesses outstanding antibacterial properties against sulphur oxidising bacteria Acidithiobacillus thiooxidans, inhibiting biofilm formation on the surface and reducing corrosion depth. The main biodegradation products of geopolymers are gypsum and silica-rich gels, resulted from decalcification and dealumination of Si–O–Al and Ca–O bonds in K-(C)-A-S-H.</span> <br></p>