This study delves into the intricate interplay between chemical volatility and soil moisture content within the context of soil vapor extraction (SVE) for industrial pollutant remediation, investigating the key determinants of SVE’s efficiency in eliminating contaminants. Concerning chemical volatility, our research reveals a direct correlation between chemical vapor pressures and mass flow rates, demonstrating that chemicals with higher vapor pressures exhibit increased mass flow rates under consistent air flow conditions. Notably, toluene displayed a more pronounced decline in mass flow rate compared to xylene and ethylbenzene, suggesting potential column depletion, possibly arising from an experimental leak. These findings align with prior research highlighting SVE’s challenges in removing low-volatility chemicals, thus advocating for alternative bioremediation approaches. Additionally, regarding total petroleum hydrocarbons (TPH), SVE proved effective for low molecular weight compounds with high volatility but faced limitations with high molecular weight compounds possessing low volatility. Soil temperature reductions were observed to reduce contaminant volatility, thereby diminishing remediation efficiency. However, benzene, with its high vapor pressure, was efficiently extracted by SVE, followed by toluene, ethylbenzene, and o-xylene. Concerning moisture content, our study explored its impact on exhaust concentrations in both organic and sandy soils. Organic soils, with higher moisture content, exhibited elevated exhaust concentrations of toluene and xylene compared to sandy soils. Conversely, benzene displayed higher exhaust concentrations in sandy soil, indicating that higher vapor pressures can overcome moisture-related constraints. In this study, dry sandy soil outperformed soil with 7.6% moisture content at a specific air flow rate, with exhaust concentration decreasing as moisture content increased. The study also reaffirmed earlier findings of a reduction in the mass transfer coefficient due to declining non-aqueous phase liquid (NAPL) saturation, primarily driven by evaporation-induced reduction in interfacial area. This study underscores the intricate relationship between chemical properties, moisture content, and SVE efficacy in pollutant remediation, offering valuable insights for shaping environmentally sound and effective remediation strategies.

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Exploring the Nexus of Chemical Volatility and Soil Moisture in Soil Vapor Extraction for Industrial Pollutant Remediation—An Efficiency Analysis

  • Rajan Ray,
  • Grant Hilbers,
  • Nihar Biswas

摘要

This study delves into the intricate interplay between chemical volatility and soil moisture content within the context of soil vapor extraction (SVE) for industrial pollutant remediation, investigating the key determinants of SVE’s efficiency in eliminating contaminants. Concerning chemical volatility, our research reveals a direct correlation between chemical vapor pressures and mass flow rates, demonstrating that chemicals with higher vapor pressures exhibit increased mass flow rates under consistent air flow conditions. Notably, toluene displayed a more pronounced decline in mass flow rate compared to xylene and ethylbenzene, suggesting potential column depletion, possibly arising from an experimental leak. These findings align with prior research highlighting SVE’s challenges in removing low-volatility chemicals, thus advocating for alternative bioremediation approaches. Additionally, regarding total petroleum hydrocarbons (TPH), SVE proved effective for low molecular weight compounds with high volatility but faced limitations with high molecular weight compounds possessing low volatility. Soil temperature reductions were observed to reduce contaminant volatility, thereby diminishing remediation efficiency. However, benzene, with its high vapor pressure, was efficiently extracted by SVE, followed by toluene, ethylbenzene, and o-xylene. Concerning moisture content, our study explored its impact on exhaust concentrations in both organic and sandy soils. Organic soils, with higher moisture content, exhibited elevated exhaust concentrations of toluene and xylene compared to sandy soils. Conversely, benzene displayed higher exhaust concentrations in sandy soil, indicating that higher vapor pressures can overcome moisture-related constraints. In this study, dry sandy soil outperformed soil with 7.6% moisture content at a specific air flow rate, with exhaust concentration decreasing as moisture content increased. The study also reaffirmed earlier findings of a reduction in the mass transfer coefficient due to declining non-aqueous phase liquid (NAPL) saturation, primarily driven by evaporation-induced reduction in interfacial area. This study underscores the intricate relationship between chemical properties, moisture content, and SVE efficacy in pollutant remediation, offering valuable insights for shaping environmentally sound and effective remediation strategies.