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Optimization of Copper Stain Removal from Marble through the Formation of Cu(II) Complexes in Agar Gels

Copper complexes with different ligands (ethylenediaminetetraacetic acid, EDTA, ammonium citrate tribasic, TAC, and alanine, ALA) were studied in aqueous solutions and hydrogels with the aim of setting the optimal conditions for copper stain removal from marble by agar gels, with damage minimization...

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Autores principales: Sansonetti, Antonio, Bertasa, Moira, Corti, Cristina, Rampazzi, Laura, Monticelli, Damiano, Scalarone, Dominique, Sassella, Adele, Canevali, Carmen
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2021
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8395995/
https://www.ncbi.nlm.nih.gov/pubmed/34449612
http://dx.doi.org/10.3390/gels7030111
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author Sansonetti, Antonio
Bertasa, Moira
Corti, Cristina
Rampazzi, Laura
Monticelli, Damiano
Scalarone, Dominique
Sassella, Adele
Canevali, Carmen
author_facet Sansonetti, Antonio
Bertasa, Moira
Corti, Cristina
Rampazzi, Laura
Monticelli, Damiano
Scalarone, Dominique
Sassella, Adele
Canevali, Carmen
author_sort Sansonetti, Antonio
collection PubMed
description Copper complexes with different ligands (ethylenediaminetetraacetic acid, EDTA, ammonium citrate tribasic, TAC, and alanine, ALA) were studied in aqueous solutions and hydrogels with the aim of setting the optimal conditions for copper stain removal from marble by agar gels, with damage minimization. The stoichiometry and stability of copper complexes were monitored by ultraviolet-visible (UV-Vis) spectroscopy and the symmetry of Cu(II) centers in the different gel formulations was studied by electron paramagnetic resonance (EPR) spectroscopy. Cleaning effectiveness in optimized conditions was verified on marble laboratory specimens through color variations and by determining copper on gels by inductively coupled plasma-mass spectrometry (ICP-MS). Two copper complexes with TAC were identified, one having the known stoichiometry 1:1, and the other 1:2, Cu(TAC)(2), never observed before. The stability of all the complexes at different pH was observed to increase with pH. At pH 10.0, the gel’s effectiveness in removing copper salts from marble was the highest in the presence of ALA, followed by EDTA, TAC, and pure agar gel. Limited damage to the marble surface was observed when gels with added EDTA and TAC were employed, whereas agar gel with ALA was determined to be the most efficient and safe cleaning material.
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spelling pubmed-83959952021-08-28 Optimization of Copper Stain Removal from Marble through the Formation of Cu(II) Complexes in Agar Gels Sansonetti, Antonio Bertasa, Moira Corti, Cristina Rampazzi, Laura Monticelli, Damiano Scalarone, Dominique Sassella, Adele Canevali, Carmen Gels Article Copper complexes with different ligands (ethylenediaminetetraacetic acid, EDTA, ammonium citrate tribasic, TAC, and alanine, ALA) were studied in aqueous solutions and hydrogels with the aim of setting the optimal conditions for copper stain removal from marble by agar gels, with damage minimization. The stoichiometry and stability of copper complexes were monitored by ultraviolet-visible (UV-Vis) spectroscopy and the symmetry of Cu(II) centers in the different gel formulations was studied by electron paramagnetic resonance (EPR) spectroscopy. Cleaning effectiveness in optimized conditions was verified on marble laboratory specimens through color variations and by determining copper on gels by inductively coupled plasma-mass spectrometry (ICP-MS). Two copper complexes with TAC were identified, one having the known stoichiometry 1:1, and the other 1:2, Cu(TAC)(2), never observed before. The stability of all the complexes at different pH was observed to increase with pH. At pH 10.0, the gel’s effectiveness in removing copper salts from marble was the highest in the presence of ALA, followed by EDTA, TAC, and pure agar gel. Limited damage to the marble surface was observed when gels with added EDTA and TAC were employed, whereas agar gel with ALA was determined to be the most efficient and safe cleaning material. MDPI 2021-08-06 /pmc/articles/PMC8395995/ /pubmed/34449612 http://dx.doi.org/10.3390/gels7030111 Text en © 2021 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Sansonetti, Antonio
Bertasa, Moira
Corti, Cristina
Rampazzi, Laura
Monticelli, Damiano
Scalarone, Dominique
Sassella, Adele
Canevali, Carmen
Optimization of Copper Stain Removal from Marble through the Formation of Cu(II) Complexes in Agar Gels
title Optimization of Copper Stain Removal from Marble through the Formation of Cu(II) Complexes in Agar Gels
title_full Optimization of Copper Stain Removal from Marble through the Formation of Cu(II) Complexes in Agar Gels
title_fullStr Optimization of Copper Stain Removal from Marble through the Formation of Cu(II) Complexes in Agar Gels
title_full_unstemmed Optimization of Copper Stain Removal from Marble through the Formation of Cu(II) Complexes in Agar Gels
title_short Optimization of Copper Stain Removal from Marble through the Formation of Cu(II) Complexes in Agar Gels
title_sort optimization of copper stain removal from marble through the formation of cu(ii) complexes in agar gels
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8395995/
https://www.ncbi.nlm.nih.gov/pubmed/34449612
http://dx.doi.org/10.3390/gels7030111
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