Jean-Michel Guillot

Use of poly(ethylene terephtalate) film bag to sample and remove humidity from atmosphere containing volatile organic compounds.

Nalophan bags made from poly(ethylene terephtalate) film are often used to collect odorous gases. In this paper, the sample water removal method, based on humidity diffusion through the sample bag film, was applied using Nalophan bags and Tedlar bags to sample volatile organic compounds (VOCs) at low concentration (10 microg/m(3)). The removal of water with Nalophan bags enabled a reduction in relative humidity (RH) in a 10-L air sample from 80% to 20% in 2h at 20 degrees C. The use of Nalophan bags for the removal of water did not involve significant VOC loss among the 11 compounds studied.

The future European standard to determine odour in ambient air by using field inspection.

This paper presents the methodologies to determine odour in ambient air by field inspection that will be a new European standard. The objective is to characterise the odour in a defined area. Without making a link with potential annoyance due to the presence of odours, the described methods propose the way to characterise an exposed environment. Two approaches are defined in the new standard: the grid method and the plume method. The grid method can be used to determine the exposure to ambient odours in a defined area of study, using direct observation of recognisable odours in the field by human panel members. This method must be applied over a sufficiently long period of time (6 or 12 months) to be representative of the meteorological conditions of that location. The result is the distribution of the frequency of exposure to odours within the assessment area. The plume method can be used to determine the extent of detectable and recognisable odours from a specific source using direct observation in the field by human panel members under specific meteorological conditions.

A methodological approach to N,N-dialkylamide thermal degradation at low temperatures

N,N-dialkylamides such as N,N-di-(2-ethylhexyl)-3,3-dimethylbutyramide (DEHDMBA) are of interest as extractants for the reprocessing of nuclear fuel. The aim of this study was to investigate the thermal behaviour of these extradants at low temperatures by a Doehlert experimental design. According to the three second-order models proposed, DEHDMBA degradation appeared to be complex. The oxygen level was the most influential parameter, almost four times as significant as the temperature and time. Moreover, the residual amount of DEHDMBA between 174 and 215 °C in ambient air could be predicted very accurately within 6%, which was close to the experimental error. The formation of the major degradation products was also very dependent on the oxygen level. However, yields of low molecular weight carboxylic acids and primary amides were increased by operating at high temperature and with long reaction times.

Investigation of the thermal decomposition of selected N,N-dialkylamides at low temperature

Abstract For the reprocessing of nuclear fuel, the thermal stability of extradants such as N,N-di-(2-ethylhexyl)-3,3-dimethylbutanamide (DEHDMBA) has to be known. The complexity of the reactions involved leads us to consider the thermal degradation of two N,N-dialkylamides which are similar in structure to DEHDMBA. These two models N,N-dialkylamides and DEHDMBA heated to 215 °C essentially produce acids, ketones, imides, and amides. The atmospheric oxygen level is the most influential factor on amide thermolysis. A thermal oxidation mechanism is therefore probably involved. It is shown that the two N,N-dialkylamides with long carbon chains, exhibit similar thermal behaviour. Moreover, most of the degradation products appear whatever the atmosphere and the temperature applied. Acids are often final reaction products, as are some primary amides and aldehydes. Secondary amides, sometimes partially degraded, are also identified after 2 or 3 h reaction time. Imides are generally intermediate reaction products. This separation between final products and by-products allows a schematic reaction pathway for N,N-dialkylamide thermal degradation at 215 °C to be established.

Thermal oxidation of two malonamides, extractants for minor actinides in nuclear fuel reprocessing

Abstract In this study, the thermal destruction of two potential extractants — the N , N′ -dimethyl, N , N′ -dibutyl, tetradecyl malonamide (DMDBTDMA) and the N , N′ -dimethyl, N , N′ -dibutyl, dodecylethoxy malonamide (DMDBDDEMA) — for minor actinides in nuclear fuel reprocessing was compared. The thermal destruction of a main by-product, the larger monoamide formed, was also studied for each extractant. Experiments were carried out in small reactors (closed or open) with different oxidising atmospheres. The recuperation of the syrupy degradation mixture, with ethyl acetate, was the first step of analysis before separation by Gas Chromatography (GC). The quantitation of separated by-products was performed with a Flame Ionisation Detector (FID) and the identification was realized by both Fourier Transform Infrared Spectroscopy (FTIR) and Mass Spectrometry (MS). Several by-products are identified and are obtained by cleavages of covalent bond and/or oxidation. After 1 h at 250°C, under oxygen flow in an open reactor, residual levels of DMDBTDMA and DMDBDDEMA pure solutions are 10 and 12% respectively, showing that the behaviour of both diamides seems similar. However, the destruction level of initial molecule do not inform on the global degradation of such complex structures. Initial diamides can lose their methyl and/or butyl groups and then give another malonamides. Its can also lead to monoamide by cleavage of CCO malonamide bond. One of these monoamide, the major by-product, can represent 13% of conversion from initial diamide with conditions described previously. An index of degradation based on the molecular weight of residual products, was calculated so as to compare the efficiency of thermal oxidation. Behaviour of diamides was also followed by thermal differential analysis (TDA) and thermal gravimetric analysis (TGA) coupled with FTIR. These techniques has shown that carbon dioxide can be produced at temperature around 250°C.

Comparison of different approaches for odour impact assessment: dispersion modelling (CALPUFF) vs field inspection (CEN/TC 264)

Odour impact assessment has become an important environmental issue. Different approaches can be used in order to evaluate the odour impact on receptors, and therefore to regulate it. Among the different possible regulation approaches, the use of dispersion modelling is suggested or required by several national or regional legislations. The wide diffusion of this approach is probably due to the fact that odour dispersion modelling is relatively cheap and results are easily understandable. Another kind of approach attempts to evaluate the odour impact directly in the field relying on a panel of trained human assessors (field inspection). The growing importance of this odour impact assessment method is proved by the current draft of a European Standard (CEN/TC 264), which defines two different methodologies of field inspection: grid measurement and plume measurement. In this study two different approaches were compared, i.e. odour dispersion modelling and field inspection by plume measurement (with specific adaptation for the studied site), the latter consisting in using a panel of examiners for determining the absence or presence of odour downwind relative to the source, in order to evaluate the plume extent. The comparison was based on application of both methods to the assessment of the odour impact of a plant for the composting of sludge from an Italian food industry. The results show that the odour impacts assessed by the two strategies turned out to be quite comparable, thus indicating that, if opportunely applied, both approaches may be effective and complementary for odour impact assessment purposes.

Preselection test of jury for improvement of olfactometric certification efficiency

ABSTRACT To certificate an olfactometric jury, laboratories usually follow up the panelist screening methodology described in the European Standard EN 13725/2003. The procedure takes a lot of time, labour and money. In laboratory routine of LCQAr – Laboratory of Air Quality Control, of Federal University of Santa Catarina, Brazil, it was found that the efficiency of jury approvals used to be as low as around 30%. In order to improve the efficiency, a quick preselection test was proposed and tried for late certification recommended by EN 13725. The methodology to create the preselection test was based on the conceptions of the standards EN 13725 (CEN, 2003), ASTM 679 (2011) and ASTM 544 (2010). In the trial test, 31 volunteers participated and then screened according to the EN13725 standard. It was verified that the efficiency increased to 46% from about 30% after the introduction of the preselection test. The experiments were conducted at LCQAr, with the contribution of Water Research Centre of University of New South Wales, Australia

Instrumental odour monitoring: Actions for a new European standard

Odour concentration is measured sensorially, thus needing a human panel, whereas the measurement of odorous compounds is typically based on physical and chemical analysis. Some systems such as electronic noses try to correlate both approaches in order to measure odour instrumentally, which would allow monitoring odour continuously. In the domain of instrumental odour monitoring, e-noses are the main candidates, although a wide range of devices based on different sensing technologies and data processing methods can be used for this purpose. Such devices are already applied in different situations, especially for monitoring of odours in ambient air. However, up to now, there is still neither standardization nor regulatory reference for this technology. In 2015, a European working group (WG41), in the frame of technical comittee CEN/TC264 Air Quality, was established aiming to develop a standard related to instrumental odour monitoring. This paper presents the scope and the general outline of this forthcoming standard.

Experimental approach for the validation of odour dispersion modelling

Experimental Approach for the Validation of Odour Dispersion Modelling Laura Capelli*, Licinia Dentoni, Selena Sironi, Jean-Michel Guillot Politecnico di Milano, Department of Chemistry, Materials and Chemical Engineering “Giulio Natta”, Piazza Leonardo da Vinci 32, 20133 Milano, Italy Ecole des Mines d’Alès, Laboratoire Génie de l’Environment Industriel, 6 Av. de Clavières, F-30319 Ales Cedex, France laura.capelli@polimi.it