Week 14 - Controlling pollutant gasses and other risks

Question 1

Thickett 2010 practical application of sorbents

Answer 1

This paper investigates the practical application of sorbents to protect both lead and silver from corrosive gases. The quantity required and how often it needs to be replaced must be determined, as well as any potential off-gassing from the sorbents. Experiments and case studies using charcoal cloth, Corrosion Intercept, and Puraspec 5040 are presented.

Experiments and case studies were conducted to investigate the practical application of sorbents to protect lead and silver objects from ethanoic acid, hydrogen and carbonyl sulphide.

Question 2

how does activated charcoal work as a sorbent

Answer 2

Activated charcoal works as a sorbent by utilizing its high surface area to absorb gaseous and particulate pollutants from the air. It works by trapping the pollutants on its surface and within its porous structure. The carbon atoms on the surface of the activated charcoal are electrically charged, which helps to attract and hold the pollutants in place. The activated charcoal can then be replaced when it is saturated with pollutants.

Question 3

what is the difference between adsorption and absorption

Answer 3

Adsorption is the process of a substance, typically a solid, adhering to a surface or another substance. It occurs when molecules from a material (called an adsorbate) are attracted and adhere to the surface of a second material (called an adsorbent). In contrast, absorption is the process of a substance taking in or soaking up another substance, typically a liquid. It occurs when molecules from the substance being absorbed (called the absorbate) are taken in by the substance doing the absorbing (called the absorbent).

Question 4

what pollutants are released by wood such as painted oak

Answer 4

Painted oak can release pollutants such as ethanoic acid, volatile organic compounds (VOCs), formaldehyde, and other air pollutants. These pollutants are released through off-gassing, which is the release of these pollutants into the air.

Question 5

why does silver tarnish

Answer 5

Silver tarnishes when exposed to sulfur-containing gases in the air, such as hydrogen sulfide, which react with the silver to form silver sulfide. This reaction is accelerated in the presence of moisture, heat, and sunlight, causing silver to darken over time.

Question 6

Corrosion Intercept

Answer 6

Corrosion Intercept is a type of foam that is used as a passive sorbent to reduce levels of corrosion in display cases. It is composed of a patented combination of active compounds that react with corrosive gases in the air and form a protective layer around the metal surfaces of the display case. The foam has been tested in extreme conditions and shown to reduce tarnish and corrosion of silver and other metals.

Question 7

whats a quartz microbalance

Answer 7

A quartz crystal microbalance (QCM) is a device that measures changes in mass per unit area by measuring the resonant frequency of a quartz crystal resonator. The device has been used in a wide range of applications, including the measurement of thin film thickness, mass transport phenomena, surface adhesion and molecular interactions.

Question 8

Schieweck 2020 Adsorbent media for the sustainable removal of organic air pollutants from museum display cases

Answer 8

This article investigates the use of adsorbent media to reduce air pollutants in museum display cases. Experiments were conducted using activated charcoal, charcoal foams and cloths, zeolites, molecular sieves, and special materials designed for museum purposes. Results showed that pure activated charcoal was most effective in reducing pollutants quickly under both active and passive conditions. Regular monitoring is recommended when using these materials.

Question 9

modern museum enclosures vs traditional types

Answer 9

It found that modern enclosures, with airtight shells and low-emissive materials, accumulate more pollutants than traditional types. Results suggest that air exchange rates and material emission play a role in pollutant levels.

Question 10

what is the hydrolytic cleavage of acetyl esters

Answer 10

Hydrolytic cleavage of acetyl esters is a chemical reaction in which an acetyl ester is broken down into an organic acid and an alcohol by the addition of water. This process produces acetic acid, which is a secondary emission product of solvent-borne lacquers used in museum enclosures.

Question 11

what is an acetyl ester

Answer 11

An acetyl ester is an organic compound formed by the reaction between an acid and an alcohol, with the resulting compound containing an acetyl (C2H3O) group. Acetyl esters are commonly used as solvents in various industries, including paints, coatings, and adhesives. They are also used in the manufacture of pharmaceuticals, fragrances, and food ingredients.

Question 12

what is an acetyl ester

Answer 12

An acetyl ester is an organic compound formed by the reaction between an acid and an alcohol, with the resulting compound containing an acetyl (C2H3O) group. Acetyl esters are commonly used as solvents in various industries, including paints, coatings, and adhesives. They are also used in the manufacture of pharmaceuticals, fragrances, and food ingredients.

Question 13

whats formic acid

Answer 13

Formic acid is an organic compound with the chemical formula HCOOH. It is the simplest of the carboxylic acids and is a colorless, corrosive, and flammable liquid. Formic acid is found naturally in the stings and bites of ants and other insects.

Question 14

whats a carboxylic acid

Answer 14

A carboxylic acid is an organic compound that contains a carboxyl group, which consists of a carbon atom double-bonded to an oxygen atom and single-bonded to a hydroxyl group. Examples of carboxylic acids include acetic acid, propionic acid, formic acid, citric acid, and lactic acid.

Question 15

When choosing an adsorbent media for a museum display case, it is important to consider…

Answer 15

When choosing an adsorbent media for a museum display case, it is important to consider the residence time between sorbate and sorbent, the cost of the sorbent, the ability of the monitoring device to detect the specific target substances at low concentrations, and the potential for the sorbent to act as an emission source and release VOCs. It is also important to regularly monitor the saturation of the applied sorbents and the release of primary and secondary emissions.

Question 16

Ryhl-Svendsen 2009 Corrosivity measurements of indoor museum environments using lead coupons as dosimeters.pdf

Answer 16

This study examined the corrosivity of 19 indoor museum environments, using lead coupons as dosimeters to measure corrosion mass. Air quality data was gathered from three Danish museums and archives to measure relative humidity, organic acids, hydrogen sulphide, and sulphur dioxide. The results showed a correlation between the corrosion mass and individual air quality factors, as well as the combined impact of all the factors.

Question 17

what kind of corrosion is lead prone to and why does it corrode

Answer 17

Lead is prone to atmospheric corrosion, which is the corrosion caused by the presence of oxygen, water vapor and other pollutants in the atmosphere such as sulfur dioxide and hydrogen sulfide. These pollutants react with moisture in the air to form acids, which then corrode the surface of lead objects.

Atmospheric corrosion of lead objects can cause the lead to form white, powdery oxides of lead and lead hydroxide. Visually, this can appear as a white, powdery substance on the lead surface.

Question 18

(Ryhl-Svendsen 2009) this text discusses the relationship between various environmental pollutants and the corrosion formation on lead surfaces. It was found that…

Answer 18

organic acids and relative humidity had a significant linear correlation with corrosion formation, while hydrogen sulphide, sulphur dioxide, and temperature had no significant linear correlations.

Question 19

tell me more about dehumidified storage and controlled relative humidity

Answer 19

Dehumidified storage is a method of preserving objects that are sensitive to changes in relative humidity. It involves controlling the relative humidity in a storage area or showcase to a specific value, typically between 38 and 42%. This method is used to prevent bronze disease, weeping glass, cracking and exfoliating ivory and bone objects, and other deterioration caused by changes in relative humidity. The most common way to achieve this is by using a desiccant dehumidifier supplied by a company such as Munters Ltd. (Newey 1987). The relative humidity is usually monitored and adjusted as needed to maintain the desired level. This method has been used successfully to preserve a wide variety of objects in museums and other collections.

Question 20

whats a Peltier cell system

Answer 20

A Peltier cell system is a type of control system used in showcases and galleries to regulate relative humidity without the use of refrigerants or drying wheels. It relies on the thermo-electrical effect discovered by Jean Peltier in 1834, which cools air and thus dehumidifies it. A Peltier cell system can be used to control relative humidity in individual showcases or from a central unit to groups of showcases in a gallery.

Question 21

tell me more about the thermo electrical effect discovered by jean peltier

Answer 21

The thermoelectric effect discovered by Jean Peltier in 1834 states that when a junction of two dissimilar metals is subjected to a temperature gradient, a voltage is generated and the junction absorbs or liberates heat depending on the direction of current flow through the junction. This effect is known as the Peltier effect and is used in numerous modern day applications in heat pumps, refrigerators and other cooling systems. It is important in the development of energy efficient technologies such as solar energy and thermoelectric batteries.

Question 22

how does the british museum care for ancient objects like the lindow man

Answer 22

The British Museum takes a variety of measures to care for ancient objects like the Lindow Man, including controlling relative humidity in both showcases and storage areas, controlling temperature, and using specialized equipment such as humidifiers, dehumidifiers, and electronic RH/temperature probes. Additionally, they have taken steps like immersing the Lindow Man in a solution of polyethylene glycol 400 and acclimatizing him to ambient conditions prior to exhibition. These measures help to preserve the integrity of the object and ensure that it remains in good condition.

Question 23

who developed the 3-in-1 test, and the oddy test. what are these used for

Answer 23

The Oddy test was developed by M.R. Oddy in 1973, and was modified by Blackshaw and Daniels in 1979. The Oddy test is used for accelerated corrosion testing of materials such as fabrics, paints, woods, adhesives, sealants, and fittings. The 3-in-1 test was developed by Robinet and Thickett in 2003, and is used for large numbers of accelerated corrosion tests.

Question 24

how does a 3-in-1 test work

Answer 24

The 3-in-1 test is a method used to evaluate materials used in storage and display of museum collections. It combines three different tests into one, measuring the indoor pollutant gases given off by the materials, their ability to absorb water vapor and the corrosiveness of these gases to objects in the collection. The test is performed using three quickfit tubes, two of which contain materials samples and one of which contains a lead coupon as a reference. The tubes are sealed and placed in an artificial climate chamber and left for a predetermined period of time. The gases emitted by the materials are trapped in the tubes and the lead coupon is used to measure the corrosive effects of the gases. At the end of the test, the lead coupon is examined for signs of corrosion.

Question 25

whats hydrocerrusite and when would it form on lead

Answer 25

Hydrocerrusite is a corrosion product consisting of lead carbonate (PbCO3) and lead hydroxide (Pb(OH)2). It forms on lead when it is exposed to high levels of relative humidity and temperature. This can occur when the lead is in contact with wood products that contain formaldehyde, or other forms of organic compounds, as well as when the lead is exposed to salt mixtures.

Question 26

whats silver corrosion like and what causes it

Answer 26

Silver corrosion is a natural process that occurs when silver is exposed to sulfur compounds in the air, such as hydrogen sulfide and carbonyl sulfide. The sulfur compounds react with the silver, forming a tarnish layer that can turn it black or green. This tarnish can be removed with special cleaning products, but the process of corrosion is irreversible. The best way to prevent silver corrosion is to store it in a cool, dry environment and keep it away from sources of sulfur compounds.