The decline in visitors to the National Museum of Indonesia caused by the Covid-19 pandemic has impacted the room temperature, which can affect the preservation of historical objects owned by the museum, which was established on April 22, 1778.
Dr. Yuni Krisyuningsih Krisnandi, M.Sc., a chemistry expert from FMIPA UI and a speaker in the webinar titled “Preventive Is Good – Collection Preservation Strategies During the Pandemic” held online by the National Museum of Indonesia on Tuesday (August 25, 2020), discussed the appropriate chemical substances used as desiccants to care for and preserve the museum’s collections.
The chemicals in question are Bentonite and Zeolite. Dr. Yuni claimed that both substances have the advantage of being resistant to high temperatures, allowing them to keep their surroundings dry. Additionally, these two natural materials are considered environmentally friendly.
Until now, the National Museum of Indonesia has used silica gel or absorbent chemicals as desiccants to preserve its collection items.
Dr. Yuni explained that a desiccant is a substance capable of absorbing water vapor from the air, thus controlling humidity well. Silica gel, which is commonly found in shoe boxes, electronic goods, medicines, and so on, can prevent excessive humidity from forming because it has a large surface area.
“Whenever we buy new shoes or cameras, there is usually silica gel, but it’s still wrapped. If we open it, each granule can absorb a lot of water vapor because of its large surface area,” said Dr. Yuni.
After absorbing water, silica gel can also change color. For example, blue silica gel or clear silica gel added with cobalt. When the blue silica gel has absorbed a large amount of water vapor on its surface, it changes color to pink.
“This color change is due to a chemical reaction between cobalt and H2O or water vapor accumulated on the silica gel’s surface,” added Dr. Yuni.
Each museum collection item, according to Dr. Yuni, has different moisture vulnerability, which affects the type and amount of silica gel used. The higher the absorption quality, the greater the cost if used in large quantities.
The commonly used silica gel can be reused (reactivated) with the right procedure, but disposing of it can cause problems because silica gel contains heavy metals.
This background prompted Dr. Yuni to propose Bentonite and Zeolite as alternative chemicals for preserving museum collections.
Besides being resistant to high temperatures, bentonite is also claimed to be safe to use because this clay mineral is part of the layered silicate family that can bind water and is non-toxic.
Meanwhile, zeolite is a silicate mineral family with a three-dimensional structure like a building.
Zeolite is also often called a ‘molecular sieve’ or ‘molecular mesh’ because it has pores of molecular size, allowing it to separate/filter molecules of specific sizes.
Bentonite and zeolite can be suitable alternative substances if these two natural materials are modified.
Dr. Yuni mentioned that bentonite and zeolite are abundantly available in Indonesia, so they can be easily found and produced in large quantities. However, she admitted that treating these substances is not easy.
Therefore, she suggested that the National Museum of Indonesia collaborate with bentonite and zeolite mining companies.
“Because the treatment is quite complicated, the National Museum can cooperate with zeolite and bentonite mining entrepreneurs to supply these materials according to the museum’s needs,” Dr. Yuni said at the end of her presentation.
Source : https://sci.ui.ac.id/
