Acetic acid and formic acid are volatile pollutants leading to degradation of some heritage materials. They are usually determined in museum environments with various types of passive samplers. In ...this work, SKC UMEx 200 passive samplers, originally intended for sampling of
NO
2
and
SO
2
, have been validated for sampling of these organic acids. The sampling rates, extraction efficiency, loss through reverse diffusion or during storage, capacity, and detection limits were determined for both acids. For laboratory exposure, a known concentration of both acids was prepared in a flow-through reactor system at controlled temperature and humidity, the samplers were extracted, followed by analysis using ion chromatography. The sampling rates were determined to be 16.7 ml/min for acetic and 17.7 ml/min for formic acid and the detection limits for 7-day exposure were determined to be
2.1
μ
g
/
m
3
for acetic and
1.9
μ
g/m
3
for formic acid. The validated method was finally used for sampling of air in two case studies at the National Museum of Slovenia, where the concentrations in the range of 2–
54
μ
g/m
3
were determined.
“Material Analysis in Cultural Heritage” describes the application of modern analytical techniques in the studies of selected historical materials, their properties, and processes they undergo. The ...topics include glass and ceramics, metal preservation, functionality and testing of historic and modern building materials, origins of specific stones, decomposition of painting pigments, and the construction of historic violins.
A simple silver particle-modified carbon paste electrode is proposed for the determination of low concentration levels of nitrite ions. The electrode consists of a carbon powder decorated with silver ...sub-micrometre particles (AgPs) and a hydrophobic ionic liquid trihexyltetradecylphosphonium chloride as a binder. It has been shown that AgPs exhibit a strong electrocatalytic effect on the nitrite oxidation. For optimal electroanalytical performance the electrode was conditioned via silver oxidation/reduction cycle. The electrode revealed a linear square-wave voltammetric response in a wide examined concentration range of 0.05 to 1.0mmolL−1, limit of detection (LOD) of 3μmolL−1 and excellent repeatability with RSD of 0.3%.
Display omitted
•Silver sub-micrometre particle-decorated carbon-based ionic liquid paste electrode•Two-step reduction/oxidation electrode conditioning protocol•Wide linear range, favourably low LOD, and excellent repeatability for nitrite determination
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A disposable electrochemical sensor was developed for convenient detection of gaseous formaldehyde. The sensor is composed of a three-electrode screen printed system modified with ...hydrazinium polyacrylate which was synthesised to serve a dual purpose, i.e. as formaldehyde accumulation/derivatisation medium, and as polyelectrolyte enabling voltammetric measurements. It exhibited a linear response in the examined concentration range of 4–16ppm gaseous formaldehyde in combination with 120min accumulation; also sub-ppm concentration levels could be detected when the exposure time was extended.
Atmospheric gases and particulate matter (PM) in contact with the material’s surface lead to chemical and physical changes, which in most cases cause degradation of the cultural heritage material. ...Atmospheric damage and soiling are recognized as two pivotal forms of deterioration of cultural heritage materials caused by air pollution. However, the atmospheric damage effect of PM is rather complicated; its variable composition accelerates the deterioration process. Considering this, one of the important contributions of this work is to review the existing knowledge on PM influence on atmospheric damage, further recognize, and critically evaluate the main gaps in current understanding. The second phenomenon related to cultural heritage material and PM pollution is soiling. Even if soiling was recognized long ago, its definition and knowledge have not changed much for several decades. In the past, it was believed that black carbon (BC) was the primary soiling agent and that the change of the lightness could effectively measure the soiling. With the change of pollution situation, the lightness measurements do not represent the degree of soiling correctly. The additional contribution of this work is thus, the critical evaluation of soiling measurements, and accordingly, due to the change of pollution situation, redefinition of soiling is proposed. Even though numerous studies have treated soiling and atmospheric damage separately, there is an overlap between these two processes. No systematic studies exist on the synergy between soiling and atmospheric damage caused by atmospheric PM.
Particulate matter (PM) pollution is one of the major threats to cultural heritage outdoors. It has been recently implied that organic aerosols will prevail over inorganic carbon particulates in the ...future, changing the main mechanisms of damage caused by poor air quality to calcareous heritage in particular. We studied fresh particulate deposits on marble and limestone surfaces exposed to urban air in sheltered and unsheltered configurations. Due to different air pollution sources in different seasons, the amount and composition of surface deposits varied throughout the year. The main and most constant contributor to PM2.5 (particles smaller than 2.5 μm) were primary traffic emissions (30 %), followed by secondary formation of acidic inorganic aerosols, such as sulphate in summer and nitrate in winter (33 % altogether), and seasonal biomass-burning emissions (14 %). Although biomass burning is the major source of primary organic aerosols including the light-absorbing fraction that prevailed over black carbon (BC) in colder months (up to 60 % carbonaceous aerosol mass), we show that surface darkening causing the soiling effect is still governed by the minor BC fraction of atmospheric aerosols, which remained below 20 % of the carbonaceous aerosol mass throughout the year. This, however, can change in remote environments affected by biomass-burning emissions, such as winter resorts, or by rigorous BC mitigation measures in the future. In the short run, sheltered positions were less affected by different removal processes, but we show that surface deposits are not simply additive when considering longer periods of time. This must be taken into account when extrapolating surface accumulation to longer time scales.
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•Interaction between heritage materials and airborne particles is poorly understood.•Fresh deposits are characterized to be able to study aging after the deposition.•PM source apportionment is correlated with surface reflectance and chemistry.•Surface deposits resemble main PM sources but do not sum up on long time-scales.•Light absorption by black carbon causing soiling still exceeds that of brown carbon.
Dose–response functions for historic paper Menart, Eva; De Bruin, Gerrit; Strlič, Matija
Polymer degradation and stability,
12/2011, Letnik:
96, Številka:
12
Journal Article
Recenzirano
Odprti dostop
Paper degradation has been studied extensively over the past few decades from both the conservation and the material science perspectives. This review focuses on the quantifiable impacts of the ...environment and material composition, from the viewpoint of long-term storage of historic paper-based collections. Therefore, temperature, relative humidity and their variation, and pollution are of major interest while photoinitiated processes are covered only briefly.
New experiments comparing the effects of the most abundant indoor pollutants (NO
2, acetic acid and formaldehyde) and the effects of fluctuating temperature and relative humidity are also presented as part of the discussion. This work highlights the need for revision of the existing dose–response (damage) functions for paper and their further development.
This research investigates degradation of historic paper in polluted environments during long-term dark storage. In an innovative experiment, degradation rates at realistic pollution levels are ...compared with degradation rates in the absence of pollution, using a set of real historic papers. The most abundant pollutants in repositories in post-industrial environments are taken into account: acetic acid and nitrogen dioxide. Their action was assessed in terms of reduction of ‘handling’ (as defined by decrease in degree of polymerisation) and ‘display’ (as defined by discolouration) lifetimes. Extrapolations to room conditions enabled lifetime predictions in conditions that are comparable to a real archival or library repository environments while prediction uncertainties were analytically evaluated to assess the significance of conclusions. While 10 ppb of NO₂ does reduce the handling lifetime of almost all types of paper, their predicted lifetimes were still assessed to be several millennia, with the exception of acidic paper. Acetic acid at concentrations that are typical for archival and library repositories (<100 ppb) has significantly less effect than NO₂ while it does not affect display lifetimes. From a conservation management perspective, it needs to be addressed whether the predicted reductions in otherwise significant handling lifetimes are of real concern and whether air filtration in archival and library repositories is justified.
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