Novel Alkali-Activated Materials with Photocatalytic and Bactericidal Properties Based on Ceramic Tile Waste

Abstract

Ceramics tile wastes (CWs) were mechanically conditioned for the preparation of alkali-activated hybrid-cements from CW (90 wt.%) and Portland cement (10 wt.%) mixtures using sodium silicate (SS) + NaOH as alkaline activators. Molar ratios of SiO2/Al2O3 (6.3 to 7.7) and Na2O/SiO2 (0.07 to 0.16) were used. The cements were prepared at room temperature (25 °C) and characterized by mechanical and physical properties and microstructure. The optimized cement was used for the preparation of novel photoactivated composite materials by incorporating 5 and 10 wt.% TiO2 (Ti) and ZnO (Z) nanoparticles, and its self-cleaning and bactericidal properties were evaluated by means of the degradation of rhodamine-B (Rh-B) and the growth inhibition of Klebsiella pneumoniae and Pseudomonas aeruginosa bacteria. The results of this study showed that the 100SS-5Z and 50SS:50G-10Ti cements have an effective photocatalytic activity for Rh-B degradation of 98.4% and 76.4%, respectively, after 24 h. Additionally, the 100SS-5Z and 50SS:50G-10Ti cement pastes and their respective mortars were effective in inhibiting the growth of Pseudomonas Aeruginosa and Klebsiella pneumoniae bacterial strains, evidenced by the formation of bacterial inhibition halos around the sample discs. Finally, these results are novel, and open the possibility of using constructions and demolition tile waste in high proportions for the elaboration of new rendering mortar with innovative properties.

Study on the Possibilities of Developing Cementitious or Geopolymer Composite Materials with Specific Performances by Exploiting the Photocatalytic Properties of TiO2 Nanoparticles

“…SEM-EDS analyses reported by Bonilla et al [ 251 ] indicate the possibility of obtaining more homogeneous, smooth, compact surfaces with a reduced number of cracks compared to the control sample. In terms of physical-mechanical properties, a slight increase in density was observed, but, probably due to the heterogeneous distribution and agglomeration of nanoparticles both in the NT and nano-ZnO cases, the compressive strength decreased significantly by more than 2.5 times compared to the control.…”

Hybrid Cements with ZnO Additions: Hydration, Compressive Strength and Microstructure

“…Recently, a new study of hybrid cement with photocatalytic and bactericidal properties based on ceramic tile waste added with ZnO showed the possibility of using constructions and demolition tile waste in high proportions for the elaboration of new rendering mortar added with alkaline solutions and ZnO with innovative properties, such as photocatalytic and bactericidal properties [39]. As can be seen, hybrid cements have been subject to numerous investigations for different applications, evaluating features such as mechanical and thermal properties, and even more complex approaches such as reaction mechanisms.…”

Effect of Redispersible Latex Powder and Fly Ash on Properties of Mortar

“…Since the emergence of cement mortar in the 1830s, it has been widely used in various fields of civil engineering. With the continuous improvement of application technologies of cement mortar, it has become the most basic material in the field of civil engineering [1][2][3][4]. With the continuous development of science and technology, the performance of cement mortar has increasingly higher requirements, and the use of cement mortar admixture is a more obvious effect, economic, and reasonable means.…”