Assessment of the chemical-physical variables affecting the evaporation of organic compounds from aqueous solutions in a sampling wind tunnel. (April 2019)

• Record Type: Journal Article
• Authors: Invernizzi, Marzio; Bellini, Alessia; Miola, Riccardo; Capelli, Laura; Busini, Valentina; Sironi, Selena
• Is Part Of: Chemosphere. Volume 220(2019)
• Page Start: 353
• Page End: 361
• Publication Date: 2019-04
• Subjects: Pollution -- Periodicals; Pollution -- Physiological effect -- Periodicals; Environmental sciences -- Periodicals; Atmospheric chemistry -- Periodicals; 551.511
• DOI: 10.1016/j.chemosphere.2018.12.124
• Languages: English
• ISSNs: 0045-6535

Abstract

Abstract: The aim of this work is the evaluation and the analysis of the different chemical-physical variables that affect the emission of volatile organic compounds (VOC) and odours from passive liquid area sources inside a wind tunnel, which is typically used for emission sampling. Three different compounds (acetone, butanol and ethanol), having different volatilization properties (e.g., boiling point, solubility), were studied in solution with water at different concentrations. The following physical parameters affecting the VOC volatilization in the Wind Tunnel system were evaluated: the velocity of the air flowing through the device, in a range from 0.01 to about 0.05 m/s, and the temperature of both the liquid source and the sweep air flow, in a range from 12 °C to 42 °C. The experimental results were compared with the existing volatilization models available in literature. In most cases the proposed theoretical model predicts well the experimentally measured concentration. Some discrepancies were observed for lower velocities and also by moving from the room temperature (20 °C); and those were discussed by making some considerations about the volatilization phenomenon. Moreover, the study clearly shows that it is not the gas phase temperature that controls the emission, but the temperature of the liquid phase, due to the effect of the latter on the vapour pressure of the compound, which is the main driving force of the phenomenon. Highlights: Experimental trials with different temperature, kind of organic compound and concentration were made. Temperature influences more the emission from organics-water solutions than the sweep air flow rate. The temperature of the liquid phase influences the emission, not the gas phase one temperature. A theoretical model to estimate the emission from liquid source were proposed. Different approaches to describe the interface equilibrium were proposed.