One of the most fundamental explanations for why hypochlorous is a far better disinfectant than bleach has to do with pH. The pH of hypochlorous acid is almost neutral (5-7). The pH of bleach is somewhat alkaline (8-13).
Bleach’s antimicrobial qualities come from the presence of hypochlorous acid. However, due to its high pH, bleach’s hypochlorous acid eventually turns into hypochlorite, a less potent disinfectant.
The effectiveness of a chlorine solution is greatly influenced by its pH. The solution will be almost entirely hypochlorous acid at a pH of 5 to 6. Bleach production starts to rise if the pH increases over 6.
According to White’s Handbook of Chlorination, “[hypochlorous] is typically the most efficient disinfectant of the chlorine species found in diluted solution at pH values linked to water and wastewater treatment. Due to its inability to diffuse through microorganism cell walls, OCl-ion [bleach] performs relatively poorly as a disinfectant.”
Is Hypochlorous Acid The Same As Bleach
Hypochlorous acid is significantly more effective in disinfection than bleach, despite having lower pH, salt content, and chlorine parts per million. Less hypochlorous acid can still produce the same (or superior) results as bleach.
Consider it similar to the distinction between two currencies. An item will cost less in euros than in dollars if the euro is more valuable than the dollar.
You may compare the kill claims for bleach and hypochlorous acid in the table below. To be completely transparent, the information offered here is based on a survey of the peer-reviewed literature that is currently accessible for kill claims for both sodium hypochlorite and hypochlorous acid.
The ppm and pH of each chemical studied were chosen at the researchers’ discretion because the investigations were conducted independently.
Since few studies directly compare the two disinfectants, this graph shouldn’t be used as a precise instruction for switching from hypochlorous to bleach. Its objective is to give the reader a thorough grasp of the differences between chlorine concentrations and disinfectant potency of the two solutions. According to the available research, 200 ppm hypochlorous is strong enough to inactivate most enveloped viruses within 0.5 to 5 minutes.
Additionally, look at this article if you’re looking for precise ratios for alternating between hypochlorous and bleach.
Cover image from Unsplash by Clay Banks
References
1. Rossoni, E. M. M., & Gaylarde, C. C. (2000). Using epifluorescence microscopy, sodium hypochlorite and peracetic acid are compared as sanitising agents for stainless steel food processing surfaces. International Journal of Food Microbiology, 61(1), 81–85. https://doi.org/10.1016/s0168-1605(00)00369x
2. HAKIM, H., ALAM, Md. S., SANGSRIRATANAKUL, N., NAKAJIMA, K., KITAZAWA, M., OTA, M., TOYOFUKU, C., YAMADA, M., THAMMAKARN, C., SHOHAM, D., & TAKEHARA, K. (2016). Inactivation of bacteria on surfaces by sprayed slightly acidic hypochlorous acid water: in vitro experiments. Journal of Veterinary Medical Science, 78(7), 1123–1128. https://doi.org/10.1292/jvms.16-0075
Taking Care of Your Community’s Safety
Hypochlorous acid produced on-site by a generating system is the most cost-effective option from a disinfecting standpoint. Additionally, compared to other bleach-based treatments with added chlorine, it is less damaging to surfaces.
More importantly, HOCl eliminates or significantly minimises the dangers associated with bleach and other conventional disinfectants.
Despite the bleach’s chemical composition and all the instructions to keep bleach away from children, misuse still occurs.
People have burned their skin from improperly handling or applying bleach unsafely to food contact surfaces and become ill as a result.
HOCl doesn’t include any chemical elements that might harm persons when nearby. People won’t be in danger if they unintentionally consume the solution or get any of it on their skin because it can be used to disinfect food items in the same manner used to clean non-porous surfaces.
Those who have never used an on-site generation system might believe it involves a complex procedure or that adding electrolysed water to an already-existing cleaning regimen would take too much time.
The benefits of on-site generation make it appropriate for almost all commercial and public settings.
It’s a cost-effective alternative to bleach, but more than that, it can be precisely what you need to boost your cleaning routines’ efficiency.
Hypochlorous acid: What is it?
Hypochlorous acid, sometimes known as HOCl, is a weak acid. It is also known as hydrochloric acid, chlorine hydroxide, and hydrogen hypochlorite. In 1834, a French scientist named Antoine Jerome Ballard made the discovery. It is a chlorine oxyacid.
It has monovalent chlorine, which can act as an oxidising or reducing agent. It serves as a human metabolite and is an unstable acid. Being a conjugate acid of a hypochlorite, it is a member of the family of reactive oxygen species.
Uses of HOCl (Hypochlorous Acid)
- Alkenes are changed into chlorohydrins using hypochlorous acid.
- They are used in baby products and other cosmetics.
- Swimming pools use this.
- It is used to produce enough amounts of a safe disinfectant.
- It is used to transform salt water into HOCl in marine sanitation equipment.
- They are used as a dressing for wounds.
- It is applied to the treatment of numerous infections in both people and animals.
Reactions
In aqueous solutions, hypochlorous acid partly dissociates into the anion hypochlorite ClO. Here is the response:
ClO + H+ = HClO
The salts of hypochlorous acid are called hypochlorites. Sodium hypochlorite (NaClO), a component in bleach, is one of the common hypochlorites.
Hypochlorous acid is a more potent oxidant than chlorine in typical circumstances.
2 e-Cl2(g) + 2 H2O + 2 HClO(aq) + 2 H+
E equals 1.63 V where
Chlorine gas is created when hypochlorous acid and hydrochloric acid (HCl) react:
H2O + Cl2 from HClO + HCl
Chloramines are created when hypochlorous acid interacts with amines coupled with water.
NH2Cl + H2O = NH3 + HClO
Conclusion
It is often said that bleach and hypochlorous acids are the same. However, while they are both powerful cleaning agents, they are not the same. Bleach is a chemical compound that contains chlorine, while hypochlorous acid is a naturally-occurring substance produced by our immune cells.
While bleach is highly effective at killing bacteria and viruses, it can also be corrosive and toxic. Hypochlorous acid, conversely, is gentle yet still effective at killing pathogens. It has even been shown to heal wounds and reduce inflammation.
In conclusion, while both substances are potent cleaners, they are not the same. Bleach is a chemical compound, while hypochlorous acid is a naturally-occurring substance with distinct benefits.