A mathematical, experimental study on iron rings formation in porous stones

Reale, Rita; Campanella, Luigí; Sammartino, Maria Pia; Visco, Giovanni; Bretti, Gabriella; Ceseri, Maurizio; Natalini, Roberto; Notarnicola, Filippo

doi:10.1016/j.culher.2019.01.012

Cited by 8 publications

(5 citation statements)

References 14 publications

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“…Similarly, the rust stains produced by corrosion of iron objects placed in proximity to marbles or carbonate stones were frequently observed on ancient and modern monuments [10,11]: iron (III) compounds were easily identified by surface analysis techniques [12][13][14]. Furthermore, attention was paid to understanding the formation and growth of iron oxides on carbonate stones and to the influence of environmental and biological factors contributing to the weathering processes.…”

Section: Introductionmentioning

confidence: 99%

A green approach to clean iron stains from marble surfaces

et al. 2022

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In the field of cultural heritage restoration, the removal of iron corrosion stains is a difficult problem to deal with, especially in stone materials. Many studies in recent years have been aimed at finding simple and reliable methods using non-toxic chelating compounds. The search for natural non-toxic compounds is therefore of great relevance, especially in the conservation of cultural heritage, where the use of toxic chemical compounds often involves risks for the environment and human health. Following this trend, the purpose of this preliminary work was to verify the use of two proteins, Lactotransferrin (Ltf) and Ovotransferrin (Ovt), for the removal of iron-based stains on marble surfaces. The two proteins, whose high affinity for iron “in vivo” has been widely documented, were extracted from their natural matrices. The protein extracts were then immobilized using a common cellulose pulp. The poultices obtained were spread on the surfaces of artificially stained marble specimens and, after a set time, were easily removed. The effectiveness of the removal, visually evident, was detected by spectrocolorimetry and image analysis. The surface analyses, before and after the treatment, carried out by X-ray photoelectron spectroscopy (XPS), confirmed that both proteins have a selective and effective complexing capacity for the ferric ions of rust stains.

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Section: Introductionmentioning

confidence: 99%

A green approach to clean iron stains from marble surfaces

et al. 2022

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“…Fractures, as in Figure 1 a, can be attributed to the insertion of the pin and/or to the volume increase associated with metal oxidation. In all samples, the area surrounding the iron element shows a compact and brown coloration that penetrates the grain boundaries inside the carbonate matrix, drawing reddish brown and yellow–orange bands ( Figure 1 d–f) similar to cyclic precipitations of iron oxides, known as Liesegang rings [ 17 , 18 ].…”

Section: Resultsmentioning

confidence: 99%

Analytical Investigation of Iron-Based Stains on Carbonate Stones: Rust Formation, Diffusion Mechanisms, and Speciation

et al. 2023

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In cultural heritage, unaesthetic stains on carbonate stones due to their close contacts with metals are of concern for the preservation of sculptures, monumental facades and archeological finds of various origin and antiquities. Rust stains made up of various oxidized iron compounds are the most frequent forms of alteration. The presence of ferric iron on rust-stained marble surfaces was confirmed in previous studies and oriented the choice of the best cleaning method (based on complexing agents specific for ferric ions). However, the composition of rust stains may vary along their extension. As the corrosion of the metallic iron proceeds, if the oxygen levels in the surroundings are low and there are no conditions to favor the oxidation, ferrous ions can also diffuse within the carbonate structure and form a variety of intermediate compounds. In this study, the iron stains on archeological marbles were compared with those artificially produced on Carrara marbles and Travertine samples. The use of integrated techniques (optical and scanning electron microscopy as well as Mössbauer and XPS spectroscopy) with complementary analytical depths, has provided the overall information. Rust formation and diffusion mechanisms in carbonates were revealed together with the evolution of iron speciation and identification of phases such as ferrihydrite, goethite, maghemite, nanomagnetite, and hematite.

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“…Note that in the formula above we approximate the reaction term m w (ω ib − ω a ) with the non-standard approximation for source terms already applied in Reale et al (2019). Now, if we consider the velocity field computed in the Eq.…”

Section: Numerical Approximation Of the Mathematical Modelmentioning

confidence: 99%

A forecasting model for the porosity variation during the carbonation process

et al. 2022

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In this paper we introduce a mathematical model of concrete carbonation Portland cement specimens. The main novelty of this work is to describe the intermediate chemical reactions, occurring in the carbonation process of concrete, involving the interplay of carbon dioxide with the water present into the pores. Indeed, the model here proposed, besides describing transport and diffusion processes inside the porous medium, takes into account both fast and slow phenomena as intermediate reactions of the carbonation process. As a model validation, by using the mathematical based simulation algorithm we are able to describe the effects of the interaction between concrete and CO$$_2$$ 2 on the porosity of material as shown by the numerical results in substantial accordance with experimental results of accelerated carbonation taken from literature. We also considered a further reaction: the dissolution of calcium carbonate under an acid environment. As a result, a trend inversion in the evolution of porosity can be observed for long exposure times. Such an increase in porosity results in the accessibility of solutions and pollutants within the concrete leading to an higher permeability and diffusivity thus significantly affecting its durability.

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A mathematical, experimental study on iron rings formation in porous stones

Cited by 8 publications

References 14 publications

A green approach to clean iron stains from marble surfaces

A green approach to clean iron stains from marble surfaces

Analytical Investigation of Iron-Based Stains on Carbonate Stones: Rust Formation, Diffusion Mechanisms, and Speciation

A forecasting model for the porosity variation during the carbonation process

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