Due to the Covid-19 crisis, we are all searching for ways to protect ourselves and our loved ones.
Recently there has been a huge upsurge in machines being offered online which claim to convert saltwater (tap water 300 ml and 60 g table salt) to a cleaning agent by running an electric current through it (USB connection 5 volts) for a few minutes, the light shuts off when completed. Having done a lot of online investigation, there is a huge amount of conflicting information on this subject. Some say the result of this is the production of Sodium Hypochlorite (NaClO), a.k.a. Bleach, which would be toxic and others say the end result is the production of HypoChlorous Acid (HClO) which is non-toxic. Additionally, I have read that even if Hypochlorous Acid is produced this way, it only retains its efficacy as a sanitizer/disinfectant for a short time. Could you please comment on this also and advise if there is a way to cause HClO to have a longer effectiveness time? Thank you.
It is actually a two-step process, with NaCl going to HCl and HOCl in a water/salt solution with electrolysis. HOWEVER, for general disinfection purposes I would highly recommend simple (and accurate) dilution of commercial bleach products. You control the dosage (AND it is variable), storage, and it really is much more convenient and inexpensive than using even DIY electrolysis setups. It may be a "survivalist" technique (despite commercial hawkers) if you only have water, salt, and a battery available. But for general use, go with the commercial bleach and dilute it.
The Toxics Use Reduction Institute (TURI) is currently researching this. We are conducting disinfection performance testing, and we are collecting water/air measurements to confirm it is a safer option.
I disagree with the previous comment about just turning to bleach for general disinfection. There are plenty of safer disinfection options to use than bleach that are also less reactive to other chemicals. Please refer to our website for more information under our COVID19 resources (www.turi.org).
I would agree that making bleach by electrolysis of aqueous salt for disinfection makes more cents for the vendor than sense for the buyer.
To be a bit more complete, the electrolysis of NaCl salt in water gives chlorine gas (Cl2) + hydrogen gas (H2) + 2 sodium hydroxides (NaOH). The chlorine, if not released, will react reversibly with water to give HOCl and HCl. In a simple undivided cell, the NaOH reacts with the HCl and HOCl and drives the equilibrium to much more stable NaOCl (sodium hypochlorite, bleach) and NaCl. Both bleach and HOCl are toxic, but HOCl is in equilibrium with chlorine gas, which is worse.
Can you comment directly on the information found in this link I will provide? There seams to be evidence provided that allows the separation via membrane of desired HOCL. Link found here: Electro-Chemical Activation