Important Topic of Chemistry: Disnfectants

Introduction

• A disinfectant is a chemical agent or compound that is used to kill or inactivate germs on inert surfaces.
• Disinfectants do not always kill all germs, particularly resistant bacterial spores; they are less successful than sterilization, which is a harsh physical or chemical procedure that destroys all forms of life.
• Antimicrobial agents such as antibiotics, which destroy bacteria within the body, and antiseptics, which destroy microorganisms on live tissue, are widely distinguished from disinfectants.
• Disinfectants are also distinct from biocides, which are designed to eliminate all forms of life, not only bacteria.

Properties of Disinfectants

• An ideal disinfectant would also provide complete and total microbiological sterilization while causing no harm to people or beneficial forms of life, as well as being affordable and non-corrosive.
• However, most disinfectants are potentially dangerous (even poisonous) to people or animals by nature. As a precautionary step, most current household disinfectants contain denatonium, a very bitter chemical used to dissuade absorption. Indoors, should never be used with other cleaning agents since chemical reactions might occur.
• The disinfectant to be used is determined by the specific scenario.
• Some disinfectants have a broad spectrum (kill a large variety of germs), whilst others destroy a narrower range of disease-causing organisms but are favoured for other features (they may be non-corrosive, non-toxic, or inexpensive).

Types of Disinfectants

Among the most frequent types of disinfectants are:

1. Air disinfectants: Air disinfectants are chemical chemicals that are used to destroy germs that are floating in the air. It is also known as a disinfecting spray.
2. Alcohol: Alcohols are commonly employed as disinfectants. In this scenario, ethanol is the most typical example. Other disinfectants include chlorine in concentrations ranging from 0.2 to 0.4 in aqueous solution and sulfur dioxide, which works as a disinfectant at low concentrations.
3. Aldehydes: Aldehydes, such as formaldehyde and glutaraldehyde, exhibit broad microbicidal action as well as sporicidal and fungicidal properties. They are partially inactivated by organic debris and retain a small amount of activity.
4. Oxidizing Agents: Oxidizing agents work by oxidizing the cell membrane of microorganisms, causing a loss of structure and ultimately leading to cell lysis and death. This is how a large number of disinfectants work.

• In hospitals, hydrogen peroxide is used to clean surfaces as a high-level disinfectant, either alone or in conjunction with other chemicals. Colloidal silver is occasionally combined with hydrogen peroxide. It is frequently favoured since it produces considerably fewer allergic responses than other disinfectants. In the food packaging business, it is also used to disinfect foil containers. As an antiseptic, a 3% solution is also utilized.
• The vapour of hydrogen peroxide is used as a medicinal sterilant and as a room disinfectant. Hydrogen peroxide has the benefit of decomposing to form oxygen and water, leaving no long-term leftovers, but it is toxic, as are most other powerful oxidants, and solutions are the main irritant.
• Ozone is a gas that may be used to disinfect water, laundry, food, air, and surfaces. It is chemically aggressive and degrades numerous organic molecules, leading to quick decolourization and deodorization as well as disinfection. Ozone degrades relatively rapidly. However, due to this ozone property, ozone cannot completely replace tap water chlorination since the ozone would decay in the water pipes.
• Potassium permanganate (KMnO₄) is a purplish-black crystalline powder with a powerful oxidizing effect that colours anything it comes into contact with. This includes staining “stainless” steel, which limits its usage and forces the use of plastic or glass containers. It is used to cleanse aquariums and as a foot disinfectant before entering communal swimming pools.

5. Acids with peroxy and peroxo groups

• Peroxycarboxylic acids and inorganic peroxo acids are powerful oxidants and disinfectants.

6. Phenolics

• Some household disinfectants use phenols as active components. They’re also in several types of mouthwash, as well as disinfecting soap and handwashes. Phenol is perhaps the earliest known disinfectant. It is caustic to the skin and might be hazardous to sensitive individuals.
• Dettol, a home disinfectant and antiseptic, contains the primary component chloroxylenol.

7. Inorganic Compounds

• Chlorine, hypochlorite, and hypochlorous acid aqueous solutions come under this category. Chlorine-releasing chemicals and their salts are sometimes included in this category. Sodium hypochlorite is most commonly seen as a pale greenish-yellow dilute solution known as liquid bleach, which is a common home chemical that has been used as a disinfectant or bleaching agent since the 18th century.

Household Disinfectants

Chlorine bleach (typically a >10 percent solution of sodium hypochlorite) is the most cost-effective home disinfectant, and it is effective against most common pathogens, including disinfectant-resistant organisms such as tuberculosis, hepatitis B and C, fungi, and antibiotic-resistant strains of staphylococcus and enterococcus.

The low cost and quick action of chlorine bleach are its advantages. It is, however, hazardous to mucous membranes and skin on contact, has a strong odour, is ineffective against Giardia lamblia and Cryptosporidium, and when coupled with other cleaning agents such as ammonia and vinegar, may produce unpleasant gases such as chlorine.

The ideal approach is to not add anything other than water to home bleach. As with most disinfectants, the area to be disinfected should be cleansed before applying chlorine bleach, as the presence of organic components may render chlorine bleach ineffective.