The conservation of Mayan wall paintings at the archaeological site of Calakmul (Mexico) will be one on the subjects touched upon by Piero Baglioni (based at the University of Florence) in his invited lecture at the 3rd European Chemistry Congress in Nürnberg in September.
In a special issue of Chemistry—A European Journal, which contains papers by many of the speakers at this conference, he reports on the latest developments on the use of humble calcium and barium hydroxides nanoparticles as a versatile and highly efficient tool to combat the main degradation processes that affect wall paintings.
La Antigua Ciudad Maya de Calakmul is located in the Campeche state (Mexico) and is one of the most important cities of the Classic Maya period (AD 250–800). The excavation of this site (set up in 1993) involves, under the supervision of the archaeologist Ramon Carrasco, archaeologists, architects, engineers, conservators and epigraphists, besides other specialists. Since 2004, the Center for Colloid and Surface Science (CSGI) at the University of Florence (CSGI), and currently directed by Piero Baglioni, has been an active partner, being involved in the study of the painting technique and in the development of nanotechnology for the consolidation and protection of the wall paintings and limestone.
Over the last decades, polymers, mainly acrylic and vinyl resins, have been widely used to consolidate wall paintings and to confer protection and hydrorepellency to the painted layer. However, contrary to the expectations, polymers used for the protection of wall paintings have induced further degradation of the works of art and their chemical modifications, such as cross-linking, strongly hampers their removal. Hence, there has been a need to develop new methods of conservation.
In Florence, Piero Baglioni and his group have pioneered the use of calcium hydroxide nanoparticles to restore wall paintings, the degradation of which is basically due to the transformation of calcium carbonate into gypsum. Nanoparticles of calcium hydroxide efficiently interact with carbon dioxide to reform calcium carbonate and replace the degraded original ligand, leading to the re-cohesion of the paint layer. However, when large amounts of soluble sulfates (i.e., sodium or magnesium sulfates) are present in a wall painting, consolidation with calcium hydroxide nanoparticles might not produce durable results. In fact, sulfate ions can react with calcium hydroxide to give a double-exchange reaction, producing the slightly soluble gypsum (calcium sulfate dihydrate). Barium hydroxide nanoparticles represent a really useful alternative and a complementary tool to hinder this process. Hence, mixed formulations can be used for the pre-consolidation of surfaces largely contaminated by sulfates.
In Calakmul, Mayan paintings have been successfully treated by using a mixture of calcium and barium hydroxide nanoparticles as a dispersion in 1-propanol. The consolidation effect was significant already after one week. The result of the application is that the paintings are now stable and do not show ongoing degradation processes. Thus, nanoscience has opened up enormous potential for Cultural Heritage conservation, due to the unique properties that the reduction in particle size confers to nanomaterials compared to their micrometric counterparts.
Author: Piero Baglioni, Università degli Studi di Firenze (Italy), http://matsci.unipv.it/CSGI/proc/People.aspx?ID=35
Title: Nanoparticles for Cultural Heritage Conservation: Calcium and Barium Hydroxide Nanoparticles for Wall Painting Consolidation
Chemistry - A European Journal, Permalink to the article: http://dx.doi.org/10.1002/chem.201001443
Piero Baglioni | Wiley-VCH
Navigational view of the brain thanks to powerful X-rays
18.10.2017 | Georgia Institute of Technology
Separating methane and CO2 will become more efficient
18.10.2017 | KU Leuven
University of Maryland researchers contribute to historic detection of gravitational waves and light created by event
On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...
Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.
Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....
Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).
When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...
Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.
How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...
Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.
It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...
17.10.2017 | Event News
10.10.2017 | Event News
10.10.2017 | Event News
18.10.2017 | Physics and Astronomy
18.10.2017 | Physics and Astronomy
18.10.2017 | Life Sciences