| Summary: | During the production and laying phases of hot-mixing asphalt (HMA), various volatile organic compounds (VOCs) and noxious gases such as H<sub>2</sub>S are released into the atmosphere. These emissions are a serious environmental problem, a risk to human health, and expose workers and residents to unfriendly odours. The aim of this study was the development of a fast and sensitive analytical method to detect the H<sub>2</sub>S emitted from hot bituminous binder that is generally used in the various stages of asphalt production, processing, handling and during road construction. The method consisted in the analysis of evolved H<sub>2</sub>S from a flask with molten bitumen, using nitrogen as a carrier gas to lead the volatile compounds into a residual gas analyser equipped with a quadrupole mass spectrometer. The analysis was performed following the H<sub>2</sub>S-specific signals at <i>m</i>/<i>z</i> 33 (HS<sup>+</sup>) and at <i>m</i>/<i>z</i> 34 (H<sub>2</sub>S<sup>+</sup>) in real time, directly on the sample without laborious and expensive pre-treatments and with short response times (<6 s). Calibration with a standard mixture of 1000 ppm of H<sub>2</sub>S in nitrogen allows semi-quantitative H<sub>2</sub>S detection. The sensitivity and rapidity of the method were evaluated by quenching the release of sulphur compounds with commercial odour-suppressing agents. Upon addition of 0.1% of additive in two minutes, the H<sub>2</sub>S signal drops about 80% in two minutes, confirming the good response of the method, even with a very complex matrix.
|
|---|
