Objective
The objective of this cross-disciplinary project is to prove the feasibility of a mobile water and air pollution detection and monitoring device based on spectroscopic techniques using novel intense high frequency electrodeless discharge lamps (HFEL-s) as light sources. For this project the efforts will be focused to the detection of heavy metals (and more especially mercury) with high precision. At the end of the project two small-scale mobile demonstration devices for real-time water and air pollution detection and quality monitoring should be available. The devices are based on a new high selective technique - Zeeman Atomic Absorption Spectrometry with High Frequency Modulation (ZAAS-HFM). One of them is an analyser with low power Glow Discharge Atomisation (ZAAS-HFM-GD), another - Mercury Analyser (ZAAS-HFM-MA). Methods based on ZAAS-HFM-GD and ZAAS-HFM-MA is very suitable for determination of many heavy elements and other pollutants in situ but they are rather seldom exploited mainly because of lack of a well-adapted light source. Meanwhile ZAAS-HFM-GD and ZAAS-HFM-MA devices equipped with optimal high intensity light source could be very sensitive and detect several pollutants simultaneously with high precision.
For example, in the case of mercury determination in water, the minimal detected concentration is 1.5ng/l but the European regulations established the admissible level as low as 0.5ng/l. Such detection limits can be achieved by using ZAAS-HFM completed with special light sources (high-frequency electrodeless lamps) emitting simultaneously high intensity resonance lines with a narrow profile (almost without self-absorption). For mercury we propose to reduce the detection limit by 10-40 times by using the mercury resonance line 185 nm. In nowadays there is no mercury atomic absorption spectrometer using wavelength 185 nm as a working line although it specifies significantly higher sensitivity then used 254 nm mercury lines. It can be explained by strong absorption of 185 nm radiations by oxygen of air and relatively weak techniques of background absorption (including elimination of flicker-noise of the source of radiation). When the mercury concentration is measured in water by so-called "cold vapour" (CV) technique, first problem can be solved if nitrogen or argon will be used as a carrier gas.
Application of Zeeman atomic absorption spectrometry using high frequency modulation of light polarisation (ZAAS-HFM) is capable to solve the second problem. This high technical and practical goal is close connected with scientific calculations and measurements. To create light sources with high requirements for water analysers it is essential to understand discharge plasma physics and chemistry. Plasma in HF low-pressure discharge lamps constitutes a system very fare from the Local Thermodynamic Equilibrium (LTE) conditions. Under this condition a Coalitional-Radiative scheme including a large number of coalitional and radiative channels is necessary for the description of the plasma. Within this task a time dependent Self-Consistent Coalitional-Radiative model will be developed (HF-SCCR). The knowledge of the emission spectra and line profiles is of prime importance for pollutant quantitative tracking. Numerical code HF-SPECTRA will be created to model HF-lamp emission spectra and line profiles, including radiation trapping. To control lamp quality, electrical and spectroscopic measurements will be performed. The results will serve for determination of optimal power supply for the HF-lamps. This series will be used also to validate experimentally the HF-SCCR and HF-SPECTRA codes. At the end of project the produced mobile water analysers will be tested in nature, as example to control water pollution in Neva river, Finn Gulf, Tom river (Russia), Daugava river, Riga's Gulf (Latvia) and Garonna river (France).
Call for proposal
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31062 Toulouse
France