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Giuntoli G, Bini M, Ciuffi B, Salvadori B, Baldi G, Rosi L. Nanodispersions of TiO 2 in Water for Removing Acrylic Films Used in Conservation. Polymers (Basel) 2021; 13:polym13223966. [PMID: 34833265 PMCID: PMC8623944 DOI: 10.3390/polym13223966] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 10/25/2021] [Accepted: 11/15/2021] [Indexed: 11/16/2022] Open
Abstract
The influence of a nanodispersion of TiO2 in water (nanoparticle size: 40 nm, polydispersity index: 0.25), brushed on a Paraloid film and subjected to UV–Vis irradiation was evaluated. The TiO2 nanodispersions showed a tendency to reduce the molecular weight of Paraloid due to its photocatalytic properties. FTIR and GPC analyses and SEM images suggested the degradation of the polymer, while chromatic variations of the films were scarcely detected. This study is very remarkable in the perspective of using this material for the removal of polymeric films used in conservation.
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Affiliation(s)
- Giulia Giuntoli
- Chemistry Department “Ugo Schiff”, University of Florence, Sesto Fiorentino, 50019 Florence, Italy; (G.G.); (M.B.); (B.C.)
| | - Marta Bini
- Chemistry Department “Ugo Schiff”, University of Florence, Sesto Fiorentino, 50019 Florence, Italy; (G.G.); (M.B.); (B.C.)
| | - Benedetta Ciuffi
- Chemistry Department “Ugo Schiff”, University of Florence, Sesto Fiorentino, 50019 Florence, Italy; (G.G.); (M.B.); (B.C.)
| | - Barbara Salvadori
- Institute of Heritage Science, ISPC-CNR, Sesto Fiorentino, 50019 Florence, Italy;
| | - Giovanni Baldi
- Research Center Colorobbia, Cericol, Colorobbia Consulting, Via Pietramarina 123, Vinci, 50053 Florence, Italy;
| | - Luca Rosi
- Chemistry Department “Ugo Schiff”, University of Florence, Sesto Fiorentino, 50019 Florence, Italy; (G.G.); (M.B.); (B.C.)
- Correspondence: ; Tel.: +055-4573458
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Brunello V, Canevali C, Corti C, De Kock T, Rampazzi L, Recchia S, Sansonetti A, Tedeschi C, Cnudde V. Understanding the Microstructure of Mortars for Cultural Heritage Using X-ray CT and MIP. Materials (Basel) 2021; 14:5939. [PMID: 34683531 DOI: 10.3390/ma14205939] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/29/2021] [Revised: 09/25/2021] [Accepted: 10/06/2021] [Indexed: 11/17/2022]
Abstract
In this study, the microstructure of mock-up mortar specimens for a historic environment, composed of different mixtures, was studied using mercury intrusion porosity (MIP) and microcomputed tomography (µCT), highlighting the advantages and drawbacks of both techniques. Porosity, sphericity, and pores size distribution were studied, evaluating changes according to mortar composition (aerial and hydraulic binders, quartz sand, and crushed limestone aggregate). The µCT results were rendered using 3D visualization software, which provides complementary information for the interpretation of the data obtained using 3D data-analysis software. Moreover, µCT contributes to the interpretation of MIP results of mortars. On the other hand, MIP showed significant ink-bottle effects in lime and cement mortars samples that should be taken into account when interpreting the results. Moreover, the MIP results highlighted how gypsum mortar samples display a porosity distribution that is best studied using this technique. This multi-analytical approach provides important insights into the interpretation of the porosimetric data obtained. This is crucial in the characterization of mortars and provides key information for the study of building materials and cultural heritage conservation.
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Meléndez-Zamudio M, Bravo-Flores I, Ramírez-Oliva E, Guerra-Contreras A, Álvarez-Guzmán G, Zárraga-Nuñez R, Villegas A, Martínez-Rosales M, Cervantes J. An Approach to the Use of Glycol Alkoxysilane-Polysaccharide Hybrids in the Conservation of Historical Building Stones. Molecules 2021; 26:molecules26040938. [PMID: 33578888 PMCID: PMC7916683 DOI: 10.3390/molecules26040938] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Revised: 02/02/2021] [Accepted: 02/05/2021] [Indexed: 11/16/2022] Open
Abstract
Stone consolidants have been widely used to protect historical monuments. Consolidants and hydrophobic formulations based on the use of tetraethoxysilane (TEOS) and alkylalkoxysilanes as precursors have been widely applied, despite their lack of solubility in water and requirement to be applied in organic media. In the search for a “greener” alternative based on silicon that has potential use in this field, the use of tetrakis(2-hydroxyethyl)silane (THEOS) and tris(2-hydroxyethyl)methyl silane (MeTHEOS) as precursors, due their high water solubility and stability, is proposed in this paper. It is already known that THEOS and MeTHEOS possess remarkable compatibility with different natural polysaccharides. The investigated approach uses the water-soluble silanes THEOS–chitosan and MeTHEOS–chitosan as a basis for obtaining hybrid consolidants and hydrophobic formulations for the conservation of siliceous and calcareous stones. In the case of calcareous systems, their incompatibility with alkoxysilanes is known and is expected to be solved by the developed hybrid consolidant. Their application in the conservation of building stones from historical and archeological sites from Guanajuato, México was studied. The evaluation of the consolidant and hydrophobic formulation treatment was mainly conducted by determining the mechanical properties and contact angle measurements with satisfactory results in terms of the performance and compatibility with the studied stones.
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Presentato A, Armetta F, Spinella A, Chillura Martino DF, Alduina R, Saladino ML. Formulation of Mesoporous Silica Nanoparticles for Controlled Release of Antimicrobials for Stone Preventive Conservation. Front Chem 2020; 8:699. [PMID: 32974275 PMCID: PMC7471835 DOI: 10.3389/fchem.2020.00699] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Accepted: 07/07/2020] [Indexed: 12/21/2022] Open
Abstract
The biotic deterioration of artifacts of archaeological and artistic interest mostly relies on the action of microorganisms capable of thriving under the most disparate environmental conditions. Thus, to attenuate biodeterioration phenomena, biocides can be used by the restorers to prevent or slow down the microbial growth. However, several factors such as biocide half-life, its wash-out because of environmental conditions, and its limited time of action make necessary its application repeatedly, leading to negative economic implications. Sound and successful treatments are represented by controlled release systems (CRSs) based on porous materials. Here, we report on the design and development of a CRS system based on mesoporous silica nanoparticles (MSNs), as a carrier, and loaded with a biocide. MSNs, with a diameter of 55 nm and cylindrical pores of ca. 3-8 nm arranged as parallel arrays concerning the NP diameter, and with 422 m2/g of specific surface area were synthesized by the sol-gel method assisted by oil in water emulsion. Biocide loading and release were carried out in water and monitored by UV-Vis Spectroscopy; in addition, microbiological assay was performed using as control the MCM-41 mesoporous silica loaded with the same biocide. The role of specific supramolecular interaction in regulating the release is discussed. Further, we demonstrated that this innovative formulation was useful in inhibiting the in vitro growth of Kocuria rhizophila, an environmental Gram-positive bacterial strain. Besides, the CRS here prepared reduced the bacterial biomass contaminating a real case study (i.e., stone derived from the Santa Margherita cave located in Sicily, Italy), after several months of treatment thus opening for innovative treatments of deteriorated stone artifacts.
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Affiliation(s)
- Alessandro Presentato
- Department of Biological, Chemical, and Pharmaceutical Sciences and Technology (STEBICEF), University of Palermo, Palermo, Italy
| | - Francesco Armetta
- Department of Biological, Chemical, and Pharmaceutical Sciences and Technology (STEBICEF), University of Palermo, Palermo, Italy
| | - Alberto Spinella
- Advanced Technologies Network (ATeN) Center, University of Palermo, Palermo, Italy
| | - Delia Francesca Chillura Martino
- Department of Biological, Chemical, and Pharmaceutical Sciences and Technology (STEBICEF), University of Palermo, Palermo, Italy.,Advanced Technologies Network (ATeN) Center, University of Palermo, Palermo, Italy
| | - Rosa Alduina
- Department of Biological, Chemical, and Pharmaceutical Sciences and Technology (STEBICEF), University of Palermo, Palermo, Italy
| | - Maria Luisa Saladino
- Department of Biological, Chemical, and Pharmaceutical Sciences and Technology (STEBICEF), University of Palermo, Palermo, Italy
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Marvasi M, Mastromei G, Perito B. Bacterial Calcium Carbonate Mineralization in situ Strategies for Conservation of Stone Artworks: From Cell Components to Microbial Community. Front Microbiol 2020; 11:1386. [PMID: 32714304 PMCID: PMC7341901 DOI: 10.3389/fmicb.2020.01386] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 05/29/2020] [Indexed: 12/14/2022] Open
Abstract
Calcareous stones have been widely used in artworks and buildings by almost all human cultures. Now, more than ever, the increased environmental pollution and global warming are threatening the stone cultural heritage. Weathering due to physical, chemical and biological factors results in monumental calcareous stone deterioration. These agents induce a progressive dissolution of the mineral matrix, increase porosity, and lead to structural weakening. Bacterial Calcium Carbonate Mineralization is a widespread naturally occurring process which in the last decades was proposed as an environmentally friendly tool to protect monumental and ornamental calcareous stones. The advantage of this treatment is that it mimics the natural process responsible for stone formation, producing a mineral product similar to the stone substrate. This mini review highlights the milestones of the biomineralization approaches with focus on in situ stone artworks protection. The strategies explored to date are based on three main approaches: (i) the use of allochthonous and (ii) autochthonous alive cells that, due to the bacterial metabolism, foster biomineralization; (iii) the cell-free approach which uses fractionated cellular components inducing biomineralization. We discuss the challenging aspects of all these techniques, focusing on in situ applications and suggesting perspectives based on recent advances.
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Affiliation(s)
| | | | - Brunella Perito
- Department of Biology, University of Florence, Florence, Italy
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Gherardi F, Goidanich S, Dal Santo V, Toniolo L. Layered Nano-TiO 2 Based Treatments for the Maintenance of Natural Stones in Historical Architecture. Angew Chem Int Ed Engl 2018; 57:7360-7363. [PMID: 29425408 DOI: 10.1002/anie.201712752] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 02/05/2018] [Indexed: 11/10/2022]
Abstract
Layered treatments of natural stones based on dispersions of experimental nano-TiO2 and commercial TEOS showing photocatalytic and self-cleaning properties were set up and tested. To enhance nano-TiO2 efficacy, a surface pre-treatment with tetraethyl orthosilicate was proposed to avoid the penetration of NPs into the crystalline porous substrates and to improve their adhesion to the stone. Two treatment applications (wet-on-wet and wet-on-dry) were compared, showing different results. A strong interaction Si-O-Ti was the key factor for the successful treatment, leaving the band gap and relevant properties of nano-TiO2 unaltered. The layered treatments were tested on a porous calcarenite (Noto stone) and a very compact marble (Carrara marble). The combined SiO2 -nano-TiO2 treatments can find application in suitable cases where a surface consolidation is needed, ensuring a depolluting and self-cleaning durable activity.
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Affiliation(s)
- Francesca Gherardi
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133, Milano, Italy
| | - Sara Goidanich
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133, Milano, Italy
| | - Vladimiro Dal Santo
- CNR-Istituto di Scienze e Tecnologie Molecolari, Via C. Golgi 19, 20133, Milano, Italy
| | - Lucia Toniolo
- Department of Chemistry, Materials and Chemical Engineering "Giulio Natta", Politecnico di Milano, Piazza Leonardo da Vinci, 32, 20133, Milano, Italy
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