What is the Difference Between Oxidizing and Non-oxidizing Biocides

The key difference between oxidizing and non-oxidizing biocides is that oxidizing biocides control microorganisms by oxidizing the cell structure and disrupting the nutrients from passing across the cell wall, while non-oxidizing biocides control microorganisms by interfering with reproduction, stopping respiration or breaking the cell wall.

Biocides are products used to control the growth of microbes. They have become a necessary part of all modern industrial productions. Biocides function either by killing the microorganism (biocidal effect) or by inhibiting the growth of microorganisms (biostatic effect). Therefore, biocides are mainly divided into two types: they are oxidizing and non-oxidizing biocides.

CONTENTS

1. Overview and Key Difference
2. What are Oxidizing Biocides
3. What are Non-oxidizing Biocides
4. Similarities – Oxidizing and Non-oxidizing Biocides
5. Oxidizing vs Non-oxidizing Biocides in Tabular Form
6. Summary – Oxidizing vs Non-oxidizing Biocides

What are Oxidizing Biocides?

Oxidizing biocides control microorganisms by oxidizing the cell structure and disrupting the nutrients from passing across the cell wall. They are fast microbe-killing agents and less costly in comparison to non-oxidizing biocides. Some prominent examples of oxidizing biocides are ammonium bromide, ammonium sulfate, chlorine gas, chlorine dioxide, hydrogen peroxide, halogenated alkylhaydantoin, peracetic acid, sodium hypochlorite, and sodium bromide.

Oxidizing biocides are chemicals that have the ability to kill microorganisms like bacteria through the electrochemical process of oxidation. For example, an oxidizing agent like chlorine pulls electrons in while bacteria lose electrons. This loss of electrons causes bacteria-like organisms to die or at least prevents them from continuing their growth. Oxidizing biocides are most widely used for water treatment because they are cheap, with fast action, and are effective even at relatively low concentrations. The main disadvantage of oxidizing biocides is their tendency to induce corrosion on metals due to their redox potential. For this particular reason, in industrial processes, they are often used in combination with corrosion inhibitors. Furthermore, they are affected by the variation of some parameters like pH and temperature as well. Therefore, oxidizing biocides are very sensitive to the operative conditions of the system.

What are Non-oxidizing Biocides?

Non-oxidizing biocides control microorganisms by interfering with reproduction, stopping respiration, or breaking the cell wall. They act against microorganisms like bacteria in several mechanisms, such as preventing duplication, stopping cellular processes, or destroying the cell wall. Non-oxidizing biocides do not act through redox reactions. In general, they are less reactive than oxidizing biocides. Therefore, the time required to fully eliminate bacteria is longer.

Moreover, being less reactive, non-oxidizing biocides can be stored for a very long period of time, and they are less corrosive against materials. Another advantage of non-oxidizing biocides is the great stability in solution, such as having low sensitivity to variations in pH and temperature. The main disadvantage is the persistence in solution and the risk of accumulation in wastewater. Furthermore, non-oxidizing biocides are generally toxic and harmful to the aquatic ecosystem. Some examples of non-oxidizing biocides include quats, polyquat, BHAP (2-Bromo-4-hydroxyacetophenone), bronopol, DBNPA (2-Dibromo-3-nitrilopropionamide, DTEA (2-(Decylthio) ethanamine), glutaraldehyde, and isothiazolinones.

What are the Similarities Between Oxidizing and Non-oxidizing Biocides?

• Oxidizing and non-oxidizing biocides are two main types of biocides.
• Both biocides have biocidal effects.
• Both biocides are active against microorganisms like bacteria.
• They have negative effects as well.

What is the Difference Between Oxidizing and Non-oxidizing Biocides?

Oxidizing biocides control microorganisms by oxidizing the cell structure and disrupting the nutrients from passing across the cell wall, while non-oxidizing biocides control microorganisms by interfering with reproduction, stopping respiration, or breaking the cell wall. Thus, this is the key difference between oxidizing and non-oxidizing biocides. Furthermore, oxidizing biocides are fast microbe-killing agents, while non-oxidizing biocides are not fast microbe-killing agents.

The below infographic presents the differences between oxidizing and non-oxidizing biocides in tabular form for side-by-side comparison.

Summary – Oxidizing vs Non-oxidizing Biocides

Biocides are chemicals that control the growth of microbes. Oxidizing and non-oxidizing biocides are two main types of biocides. Oxidizing biocides control microorganisms by oxidizing the cell structure and disrupting the nutrients from passing across the cell wall. Non-oxidizing biocides control microorganisms by interfering with reproduction, stopping respiration, or breaking the cell wall. So, this is the key difference between oxidizing and non-oxidizing biocides.

Reference:

1. “Oxidizing Biocides for Cooling Towers.” Chardon Labs.
2.“Non-Oxidizing Biological Control Chemicals.” Veolia Water Technologies & Solutions.

Image Courtesy:

1. “Ammonium sulfate sample” By Adam Rędzikowski – Own work (CC BY-SA 4.0) via Commons Wikimedia
2. “DBNPA-3D-balls” By Jynto (talk) – Created with Discovery Studio Visualizer. (CC0) via Commons Wikimedia