Layered Nano‐TiO₂ Based Treatments for the Maintenance of Natural Stones in Historical Architecture

Abstract

Layered treatments of natural stones based on dispersions of experimental nano-TiO 2 and commercial TEOS showing photocatalytic and self-cleaning properties were set up and tested. To enhance nano-TiO 2 efficacy,asurface pretreatment with tetraethyl orthosilicate was proposed to avoid the penetration of NPs into the crystalline porous substrates and to improve their adhesion to the stone.T wo treatment applications (wet-on-wet and wet-on-dry) were compared, showing different results.Astrong interaction SiÀOÀTi was the key factor for the successful treatment, leaving the band gap and relevant properties of nano-TiO 2 unaltered. The layered treatments were tested on ap orous calcarenite (Noto stone) and av ery compact marble (Carrara marble). The combined SiO 2 -nano-TiO 2 treatments can find application in suitable cases where as urface consolidation is needed, ensuring adepolluting and self-cleaning durable activity.

Selección de productos consolidantes. Ensayos y estudios para la cohesión del soporte del abrigo de Los Toros del Prado del Navazo (Albarracín, Teruel)

“…Los productos fueron aplicados con el método de aplicación wet on wet, ya que fueron sometidos a una experimentación previa (Serrano et al 2021). Este método consiste en aplicar una capa previa del diluyente de los productos para humectar el sustrato y después se administra el consolidante (Gherardi et al 2018).…”

Nanodispersions of TiO2 in Water for Removing Acrylic Films Used in Conservation

“…Nanostructured titanium dioxide (TiO 2 ) has long been known for its photocatalytic and superhydrophilicity properties. These properties together with its characteristics given by the low cost and wide availability, non-toxicity for the environment and living species, together with the high chemical stability [1] make it an ideal candidate for imparting self-cleaning properties to surfaces through degradation of a wide range of pollutants both organic and inorganic [2,3]. For these reasons it is currently used as an additive in paints with photocatalytic self-cleaning performance for indoor applications [4].…”

Neutron Radiography Study of Laboratory Ageing and Treatment Applications with Stone Consolidants

“…Due to their nano-metric size, the consolidating materials are said to be more reactive and possibly better able to adhere to the surfaces, able to penetrate deeper and into smaller passages, and chemically more compatible with the host substrate, as well as protecting the building material from atmospheric pollution and further environmental agents. The main inorganic nanomaterials include calcium hydroxide and calcium carbonate systems [21,22,23], different metal oxides [24,25] and colloidal nanosilica [26], either used solely or incorporated into a matrix to obtain a particle-modified consolidant [27]. As the materials are new, many aspects of their use and durability remain unknown.…”