Cultural heritage & air quality analysis

Fading colors

Understanding the reactivity of (semiconductor) pigments provides vital information on how to improve conservation strategies for works of art in order to avoid rapid degradation or discoloration of the pigments. Even more, the gained insights and strategies are easily transferable to all materials that capture light and suffer from discoloration (e.g. photovoltaics).

Fading has two main causes. Both physical (e.g. light, temperature) and chemical (e.g. salts/ambient chemical environment) parameters might induce deterioration. Lately (photo)electrochemistry is being used in our lab as a fast technique for identifying pigment degradation products and as a tool for monitoring pigment degradation processes in the aim of predicting harmful/favorable environmental conditions This method does not require lengthy exposure of the pigments to (chemical or physical) degrading agents in an artificial ageing chamber.

Key publication: A. Marchetti, R. Saniz, D. Krishnan, L. Rabbachin, G. Nuyts, S. De Meyer, J. Verbeeck, K. Janssens, C. Pelosi, D. Lamoen, B. Partoens and K. De Wael                          

Chemistry of Materials 32 (7) (2020) 2863-2873

Artgarden

Chemical characterization of particulate matter

Particulate matter (PM), which consists of a fine respirable particles suspended in the air, is one of the major health-threatening air pollutants. Anthropogenic PM sources include the burning of fossil fuels (for electricity generation, transport, industry and households), industrial processes, waste treatment and agriculture; in addition to the combustion-derived particles, vehicle traffic is also responsible for the release of abrasion metallic particles due to the wear of vehicle components and the friction between vehicles and the pavement (cars and road, trains and railway track). The large diversity of pollution sources, with especial abundance within urban environments, makes that PM pollution displays a wide range in size, shape and chemical composition. Particle characterization of the different sources of PM emissions is essential to better understand their contribution to the urban-mixed source atmosphere, as well as their relevance to human health.

We use different analytical techniques to gather chemical information on fine and coarse dust fractions collected outdoors and indoors (e.g. workplaces, heritage monuments, museums…). The elemental composition is determined by Energy Dispersive X-ray Fluorescence (EDXRF) analysis whereas; the water-soluble fraction is obtained by Ion chromatography (IC). Micro-Raman Spectroscopy is used to collect compositional information and individual particles’ size and shape is identified by Scanning Electron Microscopy (SEM). In case of airborne particles prior to analysis particles are collected by so-called impactors (Harvard or Berner impactor).