Hydrogen sulfide or sulfurated hydrogen is a chemical compound, found mostly in the biogas, natural gas and LPG. It is also found in swampy areas, volcanoes, and drain. Hydrogen sulfide is known by several names like hydrosulfuric acid, sulfa, sulfurated hydrogen, derived from the various properties. Colloquially, it is also called “rotten egg gas” because of its pungent odor
Hydrogen sulfide gas is highly flammable, toxic, odorless, colorless and. H2S is heavier than air, with a vapor density of 1.189 at an auto ignition temperature of 260 degrees Celsius. It forms a weak acid with its solubility being 2.9 g per 100 ml at 20 degrees Celsius. It is a very explosive mixture when combined with air or oxygen. The burn with a blue flame, forming SO2 and water. It also acts as a reducing agent and react with the metal ions and alcohol to form metal sulfides and mercaptans respectively.
Hydrogen sulfide may also be produced using solid organic compounds to heat sulfur and also by reducing sulfurated organic compounds by means of hydrogen. Hydrogen sulfide is produced in the laboratory by heating iron sulfide with a strong acid in a Kipp generator.
The bacterial degradation of organic material in the absence of oxygen leads to the formation of hydrogen sulphide or H2S. H2S can occur at any place where organic material at high temperature comes in contact with sulfur. Sulfate-reducing bacteria, which controls the formation of sulphide, is the result of mutant strains of Thiobacillus denitrificans. Anaerobic bacteria of the genera Desulfovibrio and Desulfotomaculum use sulfates under anaerobic conditions to oxidize organic compounds. This reaction leads to the production of energy and hydrogen sulfide as a byproduct.
SRB or self-reducing bacteria are heterotrophic organisms that make use of the thiosulphate, sulphate, sulphite, and various other sulfur ions as terminal electron acceptors in respiratory metabolism. An organic substrate, mostly a small chain acid pyruvic acid, produced by fermentation of anaerobic bacteria that act on other complex organic substrates. This substrate is needed by bacteria to form acetate.
Other life forms in the production of hydrogen sulphide
Animals and humans also plays a role in the production of hydrogen even in small quantities. Plants take in sulfate ion through the soil and convert it into plant protein, which in turn are consumed by animals to produce animal protein. When these plants and animals die, it leads to the breakdown of proteins, which leads to the production of hydrogen sulfide as a by-product. This process also involves a wide variety of actinomycetes, fungi and bacteria straight trophy Proteus vulgaris. Bacteria genera Chlorobiaceae and Chromtiacceae oxidize hydrogen sulfide photosynthetically into hydrogen sulfate. The human body also produces hydrogen sulfide, but in a meager amount. It is used by the body as a “signaling molecule,” but more of it can be fatal and result in death or serious medical risks. Thus, these are the few ways bacterial production of hydrogen sulfide occurs.