ZnO Nanoparticles for Photocatalytic Application in Alkali-Activated Materials

Abstract

This paper reports an Alkali-Activated Materials (AAM) using two different precursors, metakaolin and a metallurgical slag with photocatalytic zinc oxide nanoparticles, as novel photocatalytic composites. The photodegradation performance of the composites using methylene blue (MB) dye as a wastewater model was investigated by ultraviolet radiations (UV-vis) spectroscopy. Adsorption in dark conditions and photodegradation under UV irradiation are the mechanisms for removing MB dye. The pseudo-first-order kinetic and pseudo-second-order kinetic models were employed, and the experimental data agreed with the pseudo-second-order model in both cases with UV and without UV irradiations. As new photocatalytic materials, these composites offer an alternative for environmental applications.

Geopolymers and Functionalization Strategies for the Development of Sustainable Materials in Construction Industry and Cultural Heritage Applications: A Review

“…The same behavior toward the ultraviolet irradiation was found in geopolymers treated with ZnO or Cu 2 O nanoparticles [ 97 , 105 ]. In a work presented by Zidi et al, the nano-size ZnO incorporation in a geopolymeric matrix enhanced the mechanical and the thermal properties of the mortar under study, showing a compressive strength comparable to the Portland cement one [ 106 ].…”

“…Nanomaterials can create intelligent materials with improved rheological and mechanical properties, thanks to their small size and high surface-to-volume ratio [ 94 ]. The addition of these agents, such as nano-silica, nano alumina, TiO 2 , ZnO and graphene oxide, plays a key role in the consolidation of the innovative material, acting as nanofillers, and leading to a reduction of the inner water together with an increase in the compressive strength [ 95 , 96 , 97 , 98 , 99 , 100 ]. Recently, a study investigated the effect of a geopolymer treated with Al 2 O 3 and multi-walled carbon nanotubes (MWCNT) functionalized with hydroxyl groups [ 94 ].…”

The Suitability of Photocatalyst Precursor Materials in Geopolymer Coating Applications: A Review

“…The high compressive strength proved by the phase analysis revealed no traces of zeolite crystal peaks. Guzman-Aponte et al [113] on the other hand, employed a 0.8 ratio to achieve good workability in their investigation. Previous research from Guzman-Aponte et al [109] discussed liquid/solid ratio (L/S) was also varied in three levels, 0.35 (dry consistency), 0.40 (mean consistency), and 0.45 (fluid consistency).…”

“…This revealed that TiO 2 is highly useful for the geopolymer coating in this investigation. Guzman et al [113] demonstrates the concentration of methylene blue (MB) un dark and UV-irradiated settings for metakaolin geopolymer paste supplemented by oxide (ZnO). Throughout the first 30 min of photoactivation, the residual concentratio ZnO nanostructures changed as shown in Figure 5 [113].…”

“…Guzman et al [113] demonstrates the concentration of methylene blue (MB) un dark and UV-irradiated settings for metakaolin geopolymer paste supplemented by oxide (ZnO). Throughout the first 30 min of photoactivation, the residual concentratio ZnO nanostructures changed as shown in Figure 5 [113]. Photocatalytic activity is widely known to occur at the surface of a photocatalyst a result, the surface area of coating, which is affected by photocatalyst precursor nano ticle size, film shape, and thickness, has an influence on photocatalytic reactivity.…”