H2S (Hydrogen sulfide) and sulfured volatile organic compounds - Sources, impact, analyses, treatment processes

A "rotten egg" smell is how hydrogen sulfide is generally perceived by the general public. A characteristic odor (onions, garlic, etc.) is also associated with volatile organic sulfur compounds, such as mercaptans, sulfides, disulfides, etc. The public can easily recognize a gas leak due to the injection of a tiny amount of a specific sulfur compound into odorless natural gas.

These compounds can be released into the atmosphere naturally via volcanoes, fumaroles, anaerobic fermentation, etc., or as a result of numerous human activities, such as petrochemicals (natural gas, oil, oil shale, etc.), the paper industry, yeast production, the extraction of sulfur amino acids, rendering, wastewater treatment, waste-to-energy conversion (biogas), and material recovery (composting).

These sulfur compounds are acidic, corrosive, and toxic even in low concentrations, and they have a strong odor. They have an impact on human health, particularly when inhaled into the respiratory tract, which can be fatal at certain concentrations and exposure times. These molecules can be found in the environment (water, air, soil) and in certain plants. They are very odorous and cause olfactory nuisance. In addition, they cause significant metal corrosion problems. These few arguments show that it is necessary to control them in the ambient air or when they are released into the environment. Legislation has been put in place to define maximum levels for industrial gas emissions and also for working environments in workshops via occupational exposure limit values. In order to minimize their levels in fossil fuels and in air emissions, treatment processes have been developed and implemented.

In this article, after characterizing H ₂ S and volatile organic sulfur compounds such as mercaptans, sulfides, disulfides, etc., natural and anthropogenic sources of emissions are referenced. Their impacts on human health and the environment are discussed. Regulations impose limits on emissions and workplace environments, so it is necessary to be able to identify and quantify them. Processes for treating gaseous emissions containing H ₂ S and sulfur compounds will be described and discussed.