Biofouling Prevention of Ancient Brick Surfaces by TiO2-Based Nano-Coatings

Abstract

Brick constitutes a significant part of the construction materials used in historic buildings around the world. This material was used in Architectural Heritage for structural scope, and even for building envelopes. Thus, components made of clay brick were subjected to weathering for a long time, and this causes their deterioration. One of the most important causes for deterioration is biodeterioration caused by algae and cyanobacteria. It compromises the aesthetical properties, and, at a later stage, the integrity of the elements. In fact, traditional products used for the remediation/prevention of biofouling do not ensure long-term protection, and they need re-application over time. The use of nanotechnology, especially the use of photocatalytic products for the prevention of organic contamination of building façades is increasing. In this study, TiO2-based photocatalytic nano-coatings were applied to ancient brick, and its efficiency towards biofouling was studied. A composed suspension of algae and cyanobacteria was sprinkled on the bricks' surface for a duration of twelve weeks. Digital Image Analysis and colorimetric measurements were carried out to evaluate algal growth on specimens' surfaces. Results show that photocatalytic nano-coating was able to inhibit biofouling on bricks' surfaces. In addition, substrata (their porosity and roughness) clearly influences the adhesion of algal cells.

On the Modelling of Algal Biofouling Growth on Nano-TiO2 Coated and Uncoated Limestones and Sandstones

“…Thus, the generalization and the applicability of the model are limited to the Since the aim of this paper was the application of Avrami's theory to build a predictive model for algal biofouling growth, results focused on the interpretation of parameters, and on the reliability of the model. Further details about the influence of porosity and roughness on the biofouling process on natural stone and bricks can be found in literature [23][24][25]47]. …”

“…Experimental data necessary for the computation of Avrami's equation were supplied by [22], where an accelerated algal growth lab-scale test was performed by following [13,[23][24][25]45]. A brief summary of the experimental set-up is however reported in the following.…”

“…They seemed to be able to slow down algal biofouling when applied on low porous materials with smooth surfaces [22], even if algal growth is not inhibit on the substrate [13,[23][24][25] and to facilitate its removal on some substrates through the formation of a superficial water film [5].…”

Deterioration Mechanisms Affecting the Bricks Used in the Building of the Water Wells at Karnak Temples, Luxor, Egypt

“…* Mechanical removal of dry biological colonies from the bricks and using chemical pesticides for future resistance and prevent their growth in the future. * Use nanotechnology and treatment with Titanium oxide (TiO 2 ) nano-coating to prevent the growth of micro-algal and microorganisms on the red brick [39] and this treatment leads to improve the preservation of the physical and mechanical properties and the maintenance of aesthetic features of ancient brick with low costs [40] and allows the selfcleaning action of substrata. * Periodical and continuous monitoring the status of water wells to observe any changes in their conditions.…”

Development of Nano TiO2–Geopolymer Functional Composite as Antifouling Bricks

“…Conventionally, manufacture of bricks need to be burned and dried (traditional bricks) and it may cause air pollution in the surrounding environment [1][2]19]. Traditional bricks as a raw material in the building are vulnerable to weathering both chemically and mechanically, brittle and sensitive to the salting reaction, and directly related to the presence of micro-organisms deposit on the building [3][4][5][20][21]. Biofouling can be defined as the accumulation of micro-organisms, plants, and animals which are attached to either temporary or permanent on building facades [6].…”