Comparative Analysis of Volatile Organic Compound Purification Techniques in Complex Cooking Emissions: Adsorption, Photocatalysis and Combined Systems.

Volatile organic compounds (VOCs) are molecules present in our everyday life, and they can be positive, such as in the formation of odour and food flavour, or harmful to the environment and humans, and research is focusing on limiting their emissions. Various methods have been used to achieve this purpose. Firstly, we review three main degradation methods: activated carbon, photocatalysis and a synergetic system. We provide a general overview of the operative conditions and report the possibility of VOC abatement during cooking. Within the literature, none of these systems has ever been tested in the presence of complex matrices, such as during cooking processes. The aim of this study is to compare the three methods in order to understand the behaviour of filter systems in the case of realistically complex gas mixtures. Proton transfer reaction-mass spectrometry (PTR-MS) has been used in the real-time monitoring of volatilome. Due to the fact that VOC emissions are highly dependent on the composition of the food cooked, we evaluated the degradation capacity of the three systems for different burger types (meat, greens, and fish). We demonstrate the pros and cons of photocatalysis and adsorption and how a combined approach can mitigate the drawbacks of photocatalysis.

Exploring volatile organic compound emission from thermally modified wood by PTR-ToF-MS.

Thermal modification of wood is a well-known industrial process performed to increase the durability and dimensional stability or to change the colour of natural wood. The treatment influences many other properties of wood including the emission of volatile organic compounds (VOCs). VOC release ultimately affects the quality of indoor air and the capability of having low VOC emission is often included as a key parameter for the attribution of quality labels. In the present work, wood from six tree species was subjected to different types of treatment and VOC profiling was carried out on both treated and untreated samples by means of PTR-ToF-MS. Different types of thermal treatment were tested, involving either overpressure or vacuum and the effect of different temperature profiles was evaluated. Hardwood and softwood showed different release profiles under all tested conditions: the headspace of softwood was richer in several VOCs, such as terpenes, phenols and C6-C9 aldehydes and carboxylic acids. Upon thermal treatment, terpene emissions decreased, whereas several other VOCs, such as formic acid, formaldehyde, furfural and acetic acid, were released in higher amounts. With its high sensitivity and throughput, PTR-ToF-MS appears to be a very powerful analytical tool, useful in supporting the selection of wood materials for different end uses.