The main difference between oxidizing and non-oxidizing biocides lies in their mode of action against microorganisms:
Oxidizing Biocides:
- These biocides control microorganisms by oxidizing the cell structure and disrupting the nutrient flow across the cell wall.
- They are fast-acting and less costly compared to non-oxidizing biocides.
- Oxidizing biocides can induce corrosion on metals due to their redox potential, and they are often used in combination with corrosion inhibitors.
- They are sensitive to variations in pH and temperature, making them dependent on the operational conditions of the system.
Non-Oxidizing Biocides:
- These biocides work through various processes, such as interfering with reproduction, stopping respiration, or breaking the cell wall.
- They are generally slow-acting and require several hours up to a day to achieve the desired effect.
- Non-oxidizing biocides are less effective against extracellular polymeric substances (EPS) compared to oxidizing biocides.
- The selection of a non-oxidizing biocide depends on factors such as water pH, retention time, efficacy against various bacteria, fungus, and algae, biodegradability, toxicity, and compatibility with other chemistry.
In some cases, non-oxidizing biocides are found to be more effective and convenient than oxidizing biocides, leading to their use together in various conditions, such as cooling water systems.
Comparative Table: Oxidizing vs Non-oxidizing Biocides
Here is a table comparing oxidizing and non-oxidizing biocides:
Characteristic | Oxidizing Biocides | Non-oxidizing Biocides |
---|---|---|
Mechanism of Action | Control microorganisms by oxidizing the cell structure and disrupting cellular processes | Control microorganisms by interfering with reproduction, stopping respiration, or breaking the cell wall |
Examples | Ammonium bromide, ammonium sulfate, chlorine gas, chlorine dioxide, hydrogen peroxide, halogenated alkylhaydantoin, peracetic acid, sodium hypochlorite, and sodium bromide | 1,2-Benzisothiazolin-3-on, 2-Bromo-2-nitropropane-1,3-diol, 5-Chloro-2-methyl-4-isothiazolin-3-on, Diethyldithiocarbamate, N,N-Dimethyl-N,N-didecyl ammonium chloride, benzalkonium chloride, 2,2-Dibromo-3-nitrilopropionamide, Glutaraldehyde, Methylene bisthiocyanate, 2-Methyl-4-isothiazolin-3-on |
Effectiveness | Fast-acting and broad-spectrum activity against bacteria, fungi, and algae | Effective against specific microorganisms and can control biofilm formation and growth |
Cost | Less costly compared to non-oxidizing biocides | Generally more expensive than oxidizing biocides, but may offer specific advantages for certain applications |
Toxicity | Low toxicity and easily degradable | Can have varying levels of toxicity and biodegradability, depending on the specific biocide |
Water Conditions | Increases the redox potential (ORP) value of the system, which can be detected by sensors | May be affected by water pH, retention time, and other factors |
Both oxidizing and non-oxidizing biocides are used to control the growth of microbes in various applications, such as cooling water systems and industrial processes. In some cases, a combination of both types of biocides is used to optimize microbial control, protect equipment, and increase operational efficiency.
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- Oxidizing Agent vs Reducing Agent
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- Oxidative vs Nonoxidative Deamination
- Metal vs Nonmetal Oxides
- Epoxidation vs Oxidation
- Bleach vs Disinfectant
- Corrosion vs Oxidation
- Hydrolytic vs Oxidative Rancidity
- Oxygenation vs Oxidation
- Biodegradable vs Non-Biodegradable
- Binary Acids vs Oxyacids
- Positive vs Negative Oxidase Test
- Sodium Hypochlorite vs Hydrogen Peroxide
- Antiseptic vs Disinfectant
- Catalase vs Peroxidase
- Fungicides vs Pesticides