When it comes to disinfectants, not all solutions are created equal. While both hypochlorous acid (HOCl) and bleach (sodium hypochlorite - NaClO) originate from the chlorine family and bear resemblances in chemical structures, their disinfecting properties significantly differ due to their pH levels.
The Power of pH
HOCl maintains a near-neutral pH, ranging between 5-7, while bleach operates at a highly alkaline pH of 8-13. Herein lies the primary difference in their disinfection efficacy. The germ-killing properties of bleach come from hypochlorous acid. However, at a high pH, most of the hypochlorous acid in bleach is converted to hypochlorite, thereby decreasing its disinfection capacity.
White's Handbook of Chlorination asserts the dominance of hypochlorous acid in disinfection, stating that it remains the most effective at pH levels found in water and wastewater treatments. Conversely, hypochlorite or bleach, due to its negative charge, struggles to penetrate the cell walls of many pathogens, making it a weaker disinfectant.
The Battle Against Pathogens
The reason bleach cannot easily penetrate pathogen cell walls is rooted in their shared negative charges. Similar to how two like-charged magnets repel each other, bleach is repelled by pathogens upon contact. In contrast, hypochlorous acid, with its neutral charge, seamlessly penetrates pathogen cell walls, neutralizing them from the inside. Remarkably, our body uses this same mechanism: our white blood cells produce hypochlorous acid to combat pathogens during an immune response.
The Transition to Hypochlorous Acid
Switching from bleach to hypochlorous acid as a primary sanitizer may require minor adjustments in cleaning protocols. Pre-cleaning surfaces with soap and water to remove organic materials can amplify the disinfection process. In the absence of this initial cleaning, hypochlorous acid could expend its disinfectant properties on organic matter, rather than on eliminating hardier pathogens.
Furthermore, even with its superior disinfection power, hypochlorous acid is milder, having a lower pH, salt content, and chlorine ppm than bleach. Thus, it can achieve greater disinfection with less quantity. Imagine a stronger currency; fewer euros can buy what a higher amount of dollars can.
Disinfecting Power: Hypochlorous vs. Bleach
Below is a comparison of kill claims between hypochlorous acid and bleach, based on existing peer-reviewed literature:
While direct comparisons between the two disinfectants are scant, this table offers an insight into their relative disinfecting strengths. For instance, research suggests 200 ppm of hypochlorous acid can neutralize most enveloped viruses within 0.5 to 5 minutes.
In the battle against harmful pathogens, selecting the right disinfectant is paramount. Hypochlorous acid, with its potent germ-killing properties and minimal residual impact, emerges as a superior choice over traditional bleach. As with any disinfection strategy, understanding the science and adjusting protocols accordingly is essential to ensure optimal results.
About the Author: Adrian Fulle is the Global Chief Marketing Officer for ByoPlanet and a dedicated advocate for the well-being of people, animals, and plants. Adrian has a passion for health and sustainability and champions initiatives that promote the harmonious coexistence between these interconnected ecosystems. He is a frequent speaker and panelist on the topics of storytelling, marketing science and technology.