Preparation and characterisation of photocatalytic pigments for architectural mortar based on ultramarine blue

• Published in: Journal of sol-gel science and technology Vol. 93; no. 3; pp. 714 - 721
• Main Authors: Aranzabe, Estíbaliz, Blanco, Miren, Goitandia, Amaia M., Vidal, Karmele, Casado, María, Cubillo, Jose
• Format: Journal Article
• Language: English
• Published: New York Springer US 01-03-2020; Springer Nature B.V
• Subjects: Anatase; Ceramics; Chemistry and Materials Science; Coating; Color; Composites; Compressive strength; environment and building applications; Glass; Inorganic Chemistry; Materials Science; Mortars (material); Nanoparticles; Nanotechnology; Natural Materials; Optical and Electronic Materials; Original Paper: Sol-gel and hybrid materials for energy; Photocatalysis; Pigments; Precursors; Properties (attributes); Sol-gel processes; Titanium; Titanium dioxide; Weight; Anatase, Sol–gel; Mortar; Self-cleaning pigment; Photocatalysis
• ISSN: 0928-0707; 1573-4846
• DOI: 10.1007/s10971-019-05116-x

Architectural mortar is used in the building sector when aesthetic surface value is required and therefore, these surfaces present a great potential to be used as a solution for the reduction of atmospheric pollution. In the present work, an inorganic ultramarine blue pigment has been modified to provide the mortars with colour and photocatalytic properties, simultaneously. To modify the pigment, a sol–gel coating based on titanium n-butoxide precursor has been applied on its surface. The influence of different parameters affecting the coating formation, such as the pH and titanium weight content of the sol–gel reactants, has been studied. Moreover, the formation of a coating on the pigment’s surface with several amounts of TiO
2
anatase nanoparticles has also been explored. A pigment with better photocatalytic properties has been obtained at pH = 12 applying a coating based on titanium n-butoxide precursors (Ti precursor/pigment weight ratio = 0.5) with 2 wt.% of titania anatase nanoparticles, maintaining the original pigment colour. Moreover, mortars with the new pigment present higher flexural strength and similar compressive strengths than non-modified mortars ensuring the applicability of the pigment in the building sector.
Highlights
A photocatalytic pigment has been developed and dispersed in mortars by conventional methods to provide the mortars with colour and photocatalytic properties.
The effect of the pH, Ti weight content and addition of anatase nanoparticles in the coating around the pigment have been optimised during the sol–gel process.
The photocatalytic efficiency of the obtained mortars has been analysed for its application in the building sector.