Peracetic acid, or peroxyacetic acid, is a powerful oxidizing agent that plays a key role in various industrial, medical, food and cosmetic .
Known for its antimicrobial and disinfectant properties, it has been used for over a century as a biocide and sterilizer. This compound, which results from the combination of acetic acid and hydrogen peroxide, has gained popularity due to its ability to eliminate a wide range of pathogenic microorganisms.
In this article, we will explore the chemical properties of peracetic acid, its uses in different sectors, and its environmental impact.
1. Introduction to peracetic acid
1.1 Discovery and historical development
Peracetic acid was discovered in 1902, at the beginning of the 20th century, and its remarkable oxidizing properties were quickly recognized. However, its industrial use only truly began to develop in the mid-20th century, largely due to the large-scale production of hydrogen peroxide, one of its essential components. Initially reserved for specialized applications, its use has expanded to diverse fields, such as the food and beverage industry, medicine, and water treatment.
1.2 General characteristics of peracetic acid
Peracetic acid is a weak but highly reactive acid. It belongs to the family of oxidants, which gives it a unique ability to break the chemical bonds in the cell membranes of microorganisms. This mechanism underlies its effectiveness as a disinfectant and sterilizer. Its chemical formula, C₂H₄O₃, makes it an unstable compound that must be handled with care due to its corrosive properties and its flammability at high temperatures. At room temperature, it is a colorless liquid with a pungent, vinegar-like odor from the acetic acid it contains.
1.3 Chemical properties and reactivity
Peracetic acid is highly soluble in water, alcohol, and ether, making it suitable for use in a variety of industrial settings. It is produced by the reaction of acetic acid and hydrogen peroxide, a reversible reaction that requires stabilizers to prevent rapid product degradation. Its stability is influenced by factors such as temperature, light, and the presence of other chemicals. Under normal conditions, peracetic acid decomposes into acetic acid, oxygen, and water—non-toxic byproducts—making it an attractive solution for applications where safety and environmental impact are critical concerns.
Its high reactivity allows it to attack a wide range of microorganisms, including bacteria, fungi, and certain viruses. This ability stems from its oxidizing function, which disrupts cell membranes and destroys proteins and enzymes essential for the survival of microorganisms. However, this same reactivity can pose safety and handling challenges, requiring personal protective equipment and strict protocols for operators.
2. Chemical properties of peracetic acid
2.1 Chemical composition and reactions
Peracetic acid is formed by the reaction of acetic acid with hydrogen peroxide. This is an equilibrium reaction, and the composition of the resulting solution depends on the proportions of these two reactants as well as the temperature and pressure conditions. Peracetic acid does not occur spontaneously in nature, and its industrial production requires strict control of the reaction parameters to ensure its stability and effectiveness.
The peracetic acid molecule is composed of two carbon atoms, four hydrogen atoms, and three oxygen atoms (C₂H₄O₃). It is characterized by a peroxy group (-OO-) which gives this compound its oxidizing properties. This group is responsible for destabilizing the cell membranes of microorganisms, thus enabling their rapid destruction. It is this oxidizing property that makes peracetic acid a preferred choice in disinfection processes.
2.2 Solubility and stability
Peracetic acid is highly soluble in water, alcohol, and other organic solvents. This solubility facilitates its use in various environments and substrates, whether in the medical or industrial fields. However, due to its chemical instability, peracetic acid must be stored under specific conditions to prevent degradation. Under the influence of heat, light, or certain materials with which it comes into contact, peracetic acid decomposes into acetic acid, water, and oxygen.
Its stability can be extended by adding stabilizers to commercial formulations. These stabilizers prevent peracetic acid from decomposing too quickly, thus ensuring its effectiveness for longer periods. However, even with stabilizers, it is recommended to store peracetic acid in airtight containers, away from light and at moderate temperatures.
2.3 Differences with hydrogen peroxide
Peracetic acid and hydrogen peroxide are often compared due to their chemical similarities. However, they differ in several fundamental ways that influence their respective applications. Although both are powerful oxidants, peracetic acid is generally more effective than hydrogen peroxide as a biocide.
Hydrogen peroxide (H₂O₂) is more stable than peracetic acid, making it easier to handle and store for extended periods. However, peracetic acid is capable of destroying a wider range of microorganisms, including some resistant forms such as bacterial spores. This is why it is often preferred in environments where a higher level of disinfection is required, such as slaughterhouses or hospitals. Furthermore, peracetic acid has a faster oxidizing effect, making it an ideal choice for processes requiring continuous or large-scale disinfection.
In summary, although peracetic acid and hydrogen peroxide share some properties, their effectiveness differs depending on the context of use, and it is essential to choose the right product according to specific needs.
3. Uses of peracetic acid in industry
3.1 Use in the food industry
One of the most common uses of peracetic acid is in the food , where it is used as a disinfectant. Due to its effectiveness against a wide range of bacteria, fungi, and viruses, it is used to disinfect work surfaces, production equipment, and the food products themselves. For example, in the United States, peracetic acid is commonly used in slaughterhouses to disinfect poultry carcasses, a process that significantly reduces the bacterial load on the meat.
In Europe, its use in the food industry is subject to strict regulations, particularly regarding potential residues on food products. Companies must ensure that peracetic acid residues, after disinfection, decompose into non-toxic substances such as acetic acid, water, and oxygen before the products reach consumers. This makes peracetic acid a disinfectant of choice for environments where food safety is a top priority.
3.2 Use in the medical industry
In the medical field, peracetic acid is primarily used as a cold sterilizer for heat-sensitive medical devices, such as endoscopes. Unlike other disinfectants, peracetic acid is able to penetrate the crevices and complex components of medical instruments, thus ensuring complete sterilization.
This sterilization process is crucial in hospitals and clinics, where high-precision disinfection is necessary to prevent hospital-acquired infections. Peracetic acid, in vapor or liquid form, can effectively eliminate bacteria, viruses, and even resistant spores. It is often used as a replacement for glutaraldehyde, another disinfectant, because it acts more quickly and at lower concentrations, thus reducing risks to hospital staff and patients.
3.3 Use in the chemical and textile industries
Besides its medical and food applications, peracetic acid is also used as a bleaching agent in the paper and textile industries. Its ability to break down organic compounds makes it an effective agent for bleaching paper pulp without generating the toxic byproducts associated with the use of chlorine.
In the chemical industry, peracetic acid is used as a polymerization initiator. It plays a crucial role in the manufacture of certain types of plastics, such as epoxy resins. Its high reactivity allows it to be used in crosslinking processes, where it helps strengthen chemical bonds in polymers, thereby improving the durability and strength of the resulting materials.
3.4 Environmental impact and waste management
One of the notable advantages of peracetic acid compared to other chemicals is its low environmental impact. When used and degraded, it breaks down into non-toxic substances such as acetic acid, water, and oxygen, which are harmless to the environment. This makes it particularly attractive to industries seeking to reduce their environmental footprint.
However, in environments where large quantities of peracetic acid are used, such as wastewater treatment plants or slaughterhouses, it is essential to closely monitor concentrations in effluents. Poor waste management could lead to excessive levels of acetic acid or other byproducts that could affect aquatic ecosystems.
4. Laboratory analysis of peracetic acid
4.1 Importance of laboratory tests
Peracetic acid, as a disinfectant and oxidizing agent, must be used at specific concentrations to ensure its effectiveness. Insufficient dosage may not kill enough microorganisms, while excessive concentration could cause undesirable reactions, such as surface corrosion or risks to human health. Therefore, laboratory analyses play a crucial role in quality control and verification of peracetic acid formulations.
The food, medical, and environmental industries are particularly sensitive to these issues. For example, in hospitals, inadequate sterilization could lead to hospital-acquired infections, while in slaughterhouses, incorrect dosage could compromise food safety. Laboratory analyses allow for precise monitoring of these concentrations and ensure that products meet current safety and quality standards.
4.2 Analytical methods: common techniques
The determination of peracetic acid is generally performed using rigorous scientific methods. Among the most commonly used laboratory techniques are gas chromatography-mass spectrometry (GC-MS) and high-performance liquid chromatography (HPLC). These techniques allow for the precise detection and quantification of chemical compounds in complex matrices, such as disinfectant solutions.
Gas chromatography coupled with mass spectrometry (GC-MS)
GC -MS is particularly effective for analyzing volatile compounds, including peracetic acid. This technique separates the components of a gaseous sample based on their molecular weight and volatile properties before detecting them with high precision. This method is used to measure the concentration of peracetic acid in aqueous solutions, as well as to verify the presence of degradation byproducts such as acetic acid.
High-performance liquid chromatography (HPLC)
HPLC is another method used for the analysis of peracetic acid. It allows the separation of the components of a solution based on their interactions with a stationary phase and a liquid mobile phase. This technique is often used to verify the purity of peracetic acid solutions, as well as to detect potential contaminants. It is also effective for analyzing samples from the pharmaceutical or food industries.
Are you looking for an analysis?
5. Environmental impact of peracetic acid
5.1 Degradation of peracetic acid
One of the main advantages of peracetic acid over other disinfectants is its rapid decomposition into non-toxic substances. When used correctly, peracetic acid breaks down into acetic acid, oxygen, and water. These byproducts are not harmful to the environment, making it a preferred choice for companies looking to minimize their environmental impact.
Peracetic acid degrades primarily under the influence of light and heat, as well as through contact with certain materials. For this reason, it is important to carefully control storage conditions to maximize product stability until use. Once released into the environment, particularly into wastewater treatment systems, the molecule decomposes naturally, thus reducing the risk of long-term chemical contamination.
5.2 Risks to aquatic ecosystems
Despite its degradation into non-toxic compounds, studies have shown that peracetic acid can, under certain conditions, have ecotoxic effects on aquatic organisms, particularly if the concentrations of discharged residues are too high. The main concerns relate to acetic acid and hydrogen peroxide residues, which, although less toxic than other disinfectants, can degrade water quality and affect aquatic life.
Wastewater treatment plants must therefore carefully monitor peracetic acid discharges and implement control processes to limit concentrations in effluents. Indeed, at excessively high concentrations, peracetic acid could harm fish, invertebrates, and other organisms sensitive to sudden changes in water chemistry.
5.3 Environmental Regulations
The use of peracetic acid is subject to strict regulations in many countries to prevent any negative impact on the environment. In Europe, for example, the use of biocidal products such as peracetic acid is governed by EC Regulation No. 528/2012, which requires companies to demonstrate that their products are safe for both humans and the environment.
Companies must not only ensure their disinfection procedures comply with standards, but they must also demonstrate that peracetic acid discharges into the environment do not exceed permitted levels. These regulations encourage manufacturers to optimize the use of peracetic acid and develop more environmentally friendly effluent management practices.
5.4 Waste Management Measures
To minimize environmental risks, specific measures for managing peracetic acid residues are being implemented in many sectors. Industries that use this product on a large scale, such as slaughterhouses and wastewater treatment plants, are adopting continuous monitoring systems to control disinfectant levels in their effluents.
Some companies are investing in wastewater treatment technologies that neutralize waste before it is released into the environment. These systems often use filtration, oxidation, or chemical neutralization techniques to ensure that discharges do not exceed safety thresholds. This type of proactive management helps limit risks to aquatic ecosystems and guarantees compliance with applicable environmental standards.
6. Limitations and challenges related to the use of peracetic acid
6.1 Stability and degradation problems
One of the main challenges associated with the use of peracetic acid is its stability. Due to its unstable nature, peracetic acid rapidly decomposes into acetic acid, oxygen, and water when exposed to heat, light, or certain metallic surfaces. This rapid degradation limits the product's shelf life and requires users to maintain strict storage conditions, such as keeping it at low temperatures and away from light.
Furthermore, the degradation of peracetic acid can lead to a decrease in its effectiveness over time, making solutions less efficient for disinfection. Therefore, it is crucial to regularly monitor the active concentration of peracetic acid, especially in critical environments such as hospitals and slaughterhouses, where antimicrobial efficacy is paramount.
6.2 Corrosive effect on materials
Peracetic acid is a powerful oxidant, making it a highly effective disinfectant, but this same property also makes it corrosive to many materials, especially metals. Prolonged contact with stainless steel, aluminum, or copper surfaces can lead to progressive deterioration, which can affect production equipment in the food and beverage and medical industries.
Equipment used to store and handle peracetic acid must be made from corrosion-resistant materials, such as certain polymers or coated steels. The use of corrosion inhibitors in commercial peracetic acid formulations partially reduces these effects, but does not eliminate them entirely. This makes the selection of appropriate materials for tanks, piping, and medical devices crucial for extending their lifespan and avoiding high replacement costs.
6.3 Limitations of effectiveness on microbial biofilms
While peracetic acid is very effective at eliminating airborne microorganisms, it has limitations in treating microbial biofilms. Biofilms are colonies of bacteria that accumulate on surfaces and form a protective layer, making the microorganisms inside much more resistant to conventional disinfectants.
Peracetic acid, like other biocides, has difficulty penetrating biofilms to eliminate the bacteria within them. To overcome this problem, higher concentrations are often necessary, but this can lead to an increased risk of corrosion and irritation for users. Furthermore, prolonged or repeated treatments are sometimes required, which can reduce the product's long-term effectiveness.
6.4 Comparison with other disinfectants
Compared to other disinfectants such as chlorine or glutaraldehyde, peracetic acid offers certain advantages in terms of speed of action and reduction of toxic residues after use. However, it also has drawbacks related to its stability and limited ability to eliminate biofilms.
Chlorine, for example, is less expensive and more stable, but it is more toxic to the environment and leaves undesirable byproducts. Glutaraldehyde, on the other hand, is also a good disinfectant but presents a high risk of allergies and irritation for operators. Peracetic acid therefore stands out as an intermediate solution, offering a good compromise between antimicrobial efficacy, reduced environmental impact, and user safety, provided its limitations are properly managed.
7. Perspectives and innovations surrounding peracetic acid
7.1 Expansion of industrial applications
With evolving hygiene and disinfection needs, more and more industries are turning to peracetic acid due to its safety and efficacy advantages. Peracetic acid is already well-established in the medical and food processing sectors, but its applications could expand even further. For example, in the water treatment industry, peracetic acid is increasingly used to disinfect wastewater and prevent the spread of pathogens.
Current research aims to adapt peracetic acid for large-scale disinfection systems, such as municipal water treatment systems, where it could replace chlorine due to its breakdown into less environmentally harmful byproducts. This approach would not only protect aquatic ecosystems but also reduce the costs associated with treating chlorine byproducts.
7.2 Improvement of stability and formulations
One of the major challenges associated with peracetic acid remains its stability, which limits its shelf life and long-term effectiveness. Researchers are currently working on developing more stable formulations through the addition of more effective stabilizing agents. These improvements aim to extend the shelf life of peracetic acid solutions without compromising their disinfectant properties.
Innovation in storage materials, such as light- and moisture-resistant containers, could also improve the shelf life of peracetic acid. This would allow industries greater flexibility in product use, reducing losses and costs associated with degradation.
7.3 Integration into eco-responsible manufacturing processes
As part of global initiatives to reduce the environmental footprint of industrial processes, peracetic acid is increasingly being integrated into eco-friendly production systems. As an oxidizing agent that decomposes into harmless substances, it offers a more environmentally friendly alternative to more conventional disinfectants, such as chlorine or products containing volatile organic compounds (VOCs).
The textile industry, for example, is exploring the use of peracetic acid in bleaching processes, where it offers a significant advantage over chlorine-based bleaching agents, which generate toxic byproducts. Simultaneously, the paper industry is using peracetic acid for delignification, thereby reducing its reliance on more polluting chemicals. These approaches reflect a shift toward cleaner production, minimizing environmental impact while maintaining high disinfection standards.
7.4 Development of automated control systems
To maximize the effectiveness of peracetic acid in disinfection processes, the development of automated control systems is a major avenue for innovation. These systems are capable of monitoring the concentration of peracetic acid in industrial environments in real time, thus ensuring optimal dosage and preventing overuse or underuse of the product.
By integrating sensors and automated management technologies into production lines, companies can ensure that peracetic acid is used accurately and efficiently. This not only reduces costs but also minimizes the environmental impact associated with uncontrolled residues. These innovations could extend to hospitals, where equipment sterilization could be optimized through automated monitoring of disinfectant concentration.
7.5 Peracetic acid and the fight against emerging infections
With the rise in antibiotic-resistant infections and the increasing need for potent disinfectants, peracetic acid is also being investigated for its potential to combat emerging pathogens. Its ability to destroy resistant spores, viruses, and bacteria makes it a prime candidate in hospital settings where infection control is a top priority.
Studies are underway to determine the effectiveness of peracetic acid against newer pathogens, such as those involved in drug-resistant hospital-acquired infections. Expanding its use in healthcare settings could address the growing challenges posed by antimicrobial resistance, while also offering a safer option than other traditional disinfectants.
