Biocides are substances that have the ability to kill microorganisms. Eliminating harmful microorganisms in the water treatment and oil and gas extraction industries is of great importance, and to do this, chemicals such as isothiazoline, glutaraldehyde, chlorine, etc. are usually used. In this article, we will learn about the types of biocides, how they work and their areas of use. Biocides use different methods to disinfect and destroy microorganisms. Methods such as oxidation or dissolving fats.
In the following, you can see some biocides that can be obtained from the innovators of chemistry. Contact our experts to prepare each one.
| Isothiazoline | Glutaraldehyde | Calcium hypochlorite |
Biocides are substances that have the ability to kill microorganisms. Eliminating harmful microorganisms in the water treatment and oil and gas extraction industries is of great importance, and to do this, chemicals such as isothiazoline, glutaraldehyde, chlorine, etc. are usually used. In this article, we will learn about the types of biocides, how they work and their areas of use. Biocides use different methods to disinfect and destroy microorganisms. Methods such as oxidation or dissolving fats.
Application of biocides in oil and gas industry
Biocides in the oil and gas industry play an effective role in increasing production by preventing the formation of biofilms and corrosion in equipment. Usually, a small amount of these compounds have the ability to control the growth of bacteria and other harmful microorganisms in wells and pipelines. Choosing the right material or mixture for this work is done after preliminary tests.
Biocides in water treatment
Controlling the growth of bacteria is very important in the processes of purification, storage and use of water. In addition to the problems it can cause for human health, the presence of harmful bacteria can cause problems in other matters such as storage in tanks, transmission through pipelines, etc. Bacteria can cause corrosion in equipment and storage tanks, in addition to the films that can form over time, making it difficult for water to pass through different paths. To prevent the mentioned problems and material damages, biocides are used, which are generally based on chlorine.
Types of biocides
The history of biocides dates back to the 19th century when doctors used chlorine to disinfect their hands. Also, chlorine was considered an integral part in order to control infection in patients in addition to antibiotics. Today, biocides include different types, but based on the mechanism of activity, they into two categories : oxidizing and non-oxidizing biocides. are divided
Studies have shown that bacterial resistance to biocides is as high as chlorine resistance. The mechanism of biocide effect on salmonella, which is a type of bacteria that leads to food poisoning, is ineffective and can cause selective pressure in bacteria and their resistance. Bacteria have the ability to develop resistance to excessive use of antibiotics, so we are facing a big challenge.
Oxidizing biocides
Peroxide
Hydrogen peroxide is another strong oxidizing agent of radicals. Hydrogen peroxide acts on a wide range of microbes both extracellularly and intracellularly. Oxidation by hydroxyl radicals, for example, unsaturated acids within membrane phospholipids, leads to cellular damage and oxidation. Due to its low molecular weight compared to molecules, hydrogen peroxide can pass through microbial cell walls and membranes and act intracellularly without first inducing cell destruction. Hydroxyl radicals of intracellular proteins, enzymes, lipids and nucleosides in DNA then oxidize thiol groups.
Hydrogen peroxide is usually unstable and therefore difficult to store. It is very useful in detoxification. This substance only decomposes into water and hydrogen, so it is the right choice of disinfectant to protect the environment. It is non-toxic, so it can be used as a safe disinfectant for medical equipment and surfaces. A solution of 3 to 6 percent hydrogen peroxide in water is commonly used. In addition, hydrogen peroxide is active against various types of microorganisms, including bacteria, yeasts, and viruses.
The combination of 3.0% hydrogen peroxide along with 1.0% monophenyl glycol, 0.3% acetophosphonic acid and 3.5% lactic acid with cationic polymer is used for disinfection. This formula is more effective in reducing bacterial growth than hydrogen peroxide alone due to the reduced pH. It also has broad properties against both Gram-positive and Gram-negative bacteria and is useful for use in humid environments. Hydrogen peroxide in the form of solution, steam and sometimes in the form of foam has an effective effect on disinfection.
ozone
Ozone, like hydrogen peroxide, is a strong oxidizing agent that is active against a wide range of gram-positive and gram-negative bacteria, viruses, fungi, and protozoa. Ozone decomposes bacterial cells and lipoproteins through the oxidation of membrane phospholipids. Since ozone can be dissolved in solution or applied in gaseous form, it can be widely used in industry, especially for wastewater treatment.
Ozone gas has many advantages: it is easy to produce, has a half-life of 20 minutes, and can disinfect places that are difficult to reach using conventional soluble biocides. However, ozone can be toxic in high concentrations. Gaseous ozone may be used to disinfect hospital rooms and vehicles, while dissolved ozone may be used in water purification and food disinfection.
Chlorine releasing agents
Chlorine releasing agents (CRAs) are oxidizing agents that include sodium hypochlorite, hypochlorous acid, and sodium dichloroisocyanurate. Sodium hypochlorite (NaOCl) is a strong electrolyzed solution produced by the electrolysis of sodium chloride and contains 5 to 12% chlorine. When this solution is added to water, the hypochlorite partially dissociates into hypochlorite (OCl) ions while the rest remains as hypochlorous acid (HOCl). Both substances are oxidizing agents. For example, they can oxidize sulfhydryl groups of enzymes, which leads to disruption of DNA and protein synthesis. They also react with amino acids such as methionine, cysteine, peptides, and DNA itself.
Oxidative damage to membrane proteins may alter membrane permeability.
This can allow microbial access to oxidative species produced by HOCl that can damage the organelles. For example, the lethality of sodium hypochlorite is due to the discoloration of sulfhydryl enzymes and antioxidants such as glutathione. This disrupts cell function and leads to cell death. This biocidal mechanism applies to a variety of CRAs, including N-chloramines.
CRA is also commonly found in many household disinfectants. For example, sodium hypochlorite is commonly used in household bleach, and for this purpose it has a shelf life of at least one month at moderate temperatures.
New disinfectant sprays containing electrolyzed chlorine water are less stable. However, they have been shown to be effective in disinfecting kitchen surfaces. Sodium hypochlorite solution is also often used to disinfect medical facilities contaminated with pathogenic bacteria.
Sodium dichloroisocyanurate is only stable as a solid, not as a solution. Because of this unstable
CRAs are mostly found in industry. Hypochlorous acid (HOCl) is cheap, but toxic and can be used in mouthwashes, wound antiseptics. Interestingly, this substance is also produced by the human immune system and is part of the innate primary immunity against infectious agents. There is limited evidence of bacterial resistance to HOCl, suggesting that Gram-negative bacteria produce extracellular polymeric substances upon excessive exposure to HOCl. In general, the biocidal activity of CRA is more effective on non-porous and smooth surfaces such as 304 stainless steel and nitrile compared to porous surfaces such as wood or rubber.
Another important factor that reduces the efficiency of CRAs is the presence of organic matter. Therefore, cleaning and removal of organic matter before disinfection is recommended.
The amount of chlorine, pH level and oxidation and reduction potential can further affect the effect of CRA. Hypochlorous acid shows a high oxidation activity and therefore, a high oxidation potential.
Non-oxidizing biocides
Ammonium biocides
Quaternary ammonium cations or QACs are biocidal agents commonly used in domestic and industrial environments. QAC is used as a biocide in industry to disinfect and prevent the spread of infections. They are used to disinfect microorganisms such as fungi, bacteria, parasites and lipophilic viruses. Due to their aliphatic nature, QACs act like cationic surfactants, as a result of which they destabilize cell membranes and target enzymes and lead to cell destruction of microorganisms. For example, we can mention benzalkonium chloride and acetylpyridinium chloride, both of which can target gram-negative and gram-positive bacteria such as Escherichia coli and Staphylococcus aureus. In general, the structure N + R1R 2R 3R 4X consists of a halide anion, usually Cl or Br, attached to a nitrogen cation.
The antibacterial process by quaternary ammonium type disinfectants is such that these hydrophobic alkyl chains of QAC salt interact with the phospholipid bilayer. This increases membrane permeability and releases autolytic enzymes, resulting in bacterial cell destruction.
The QAC function changes with modifications within the R group, such as the addition of an aromatic hydrocarbon and an alkyl group. QACs with methyl groups from C12 to C16 produce the most changes in the R structure. Electrostatic adsorption of the QAC salt to the target cell results in the release of autolytic enzymes that initiate cell destruction. For example, in the food industry, benzyl dimethyl dodecyl ammonium chloride (BAC 12), benzyl dimethyl tetracid ammonium chloride (BAC 14) and benzyl dimethyl hexadecyl ammonium chloride (BAC 16) are used as disinfectants for milk tanks. take QACs like BAC 12-16 are used because of their low toxicity levels. Unlike oxidizing biocides such as hydrogen peroxide, QAC does not produce free radicals and is therefore non-carcinogenic. Therefore, it is very useful in household use. Substances such as acetylpyridinium chloride and dodecyldimethylbenzylammonium chloride are found in most cleaning liquids because they are very effective against various types. QAC is available in wipes or cleaning spray formulations.
Glutaraldehyde biocide
This non-oxidizing biocide disrupts the growth of bacteria and fungi and is widely used in industrial waters. Its solubility in water is very high and it prevents the formation of bubbles and foam in water. Its mechanism of action is on anaerobic bacteria in an environment with a high pH between 3 and 5.
biocide Glutaraldehyde is used to remove deposits, bacteria and algae in cooling systems, swimming pools and industrial waters.
The mechanism of action of glutaraldehyde biocide includes adhesion to lipids in the target cell membrane and ultimately disruption of the components inside the membrane. By attacking the protein membrane of the microorganism, they prevent food from reaching it and by damaging the bacterial cytoplasm, they cause the bacterial content to leak. This type of biocide is used in water and wastewater treatment, in oil and petrochemical industries, and disinfection of hospital equipment.
Major use of biocides
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In water and wastewater treatment
Water treatment biocides include both oxidizing and non-oxidizing biocides. along with non-oxidizing biocides such as glutaraldehydes and isothiazolin The most familiar type is chlorine, and it is used to purify water, remove deposits, sludge, and bacteria. Water biocides such as chlorine and ozone are used for disinfection in water treatment plants because the water sources are sea and river. Since all microorganisms are not completely destroyed, water entering the reverse osmosis device causes contamination of the membrane membrane. Therefore, membrane cleaning is also essential. Membrane biocides that are compatible with the structure of the membrane membrane can be very effective in this regard. Membrane biocides should be used between 3 and 10 days depending on the type of water source.
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Petrochemical and oil industries
One of the most important applications of biocides is their use as petroleum biocides. Petroleum biocides should have long life, high solubility and chemical stability. In the petrochemical industry, microorganisms cause damage to the molecular structure of oil and create hydrogen sulfide, and also lead to an increase in the viscosity of oil and sulfur. Microorganisms in oil transmission lines are the main cause of erosion, corrosion and deposits. This causes high losses and damages to the oil extraction system. As a result, petroleum biocides can play an important role in this field because there is a possibility of contamination at every stage of extraction. The type of biocides used in different oil fields is different. Due to the presence of carbon in the molecular structure of oil, it is a suitable substrate for microorganisms, and bacteria cause a decrease in the quality of oil by changing it.
Conclusion
In this review, we have described the uses of common biocides, their activity and evidence of the occurrence of bacterial resistance, but there are still limitations to the extent of knowledge about resistance to microbicide significantly in healthcare and industry to control microbial contamination. There is our current. However, their excessive use, especially in inappropriate concentrations, can contribute to increasing the resistance of bacteria to antimicrobial drugs.