Sodium Hipochlorite Homemade Production

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The homemade production of sodium hypochlorite includes common reagents, which are not dangerous and easy to acquire; In addition, simple and recycled materials are used in the manufacturing process. Sodium hypochlorite is a chemical compound with the formula NaClO, and a strongly oxidizing character. This property makes it an excellent bleach and disinfectant. Its use is recommended as an antiseptic in water (purification), household surfaces, in hospital uses, eliminating bacteria such as S. aureus, S. pneumoniæ, E. coli; as well as viruses, parasites and fungi. It is one of the most effective disinfectants available.

Sodium hypochlorite is manufactured by electrolysis of a solution of sodium chloride (common salt). In this process a low voltage current is conducted through the solution. In this way, sodium chloride and water are separated into the elements that constitutes it: H2O water (really HOH) is separated into hydronium (H +) ions that are reduced to form H2 gaseous hydrogen, and (OH-) hydroxyls; Sodium chloride, of the NaCl formula, is separated into Sodium Na + and Cl- chloride ions, the latter are oxidized and converted into chlorine gas Cl2.
Thus, under the same principle of "opposite charges are attracted", chloride and hydroxides (negatively charged) are attracted to the positive electrode, and sodium and hydroniums (positive) are attracted to the negative electrode:
The reaction is observed in the image: the chloride and hydronium ions escape in the form of chlorine gas and hydrogen respectively, leaving in solution sodium Na + and hydroxides OH-, which form Sodium Hydroxide (NaOH) in solution. When the chlorine gas passes through the sodium hydroxide formed, it reacts, and sodium hypochlorite is formed, plus sodium chloride and water:

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NaOH + Cl2 = NaClO + NaCl + H2O.
It should be noted that chlorine gas is formed in the positive electrode, which is very corrosive to metals. For this reason it is convenient to use graphite electrodes, since it is inert to gas, along with gold and platinum. If a copper or iron electrode is used, the solution would be contaminated with copper or iron chloride, both toxic, and hypochlorite would not form.
For the artisanal manufacture, you should use cooking salt and water.
Materials: Common Salt, Plastic Bottle, Water, Electric Transformer (phone or laptop charger,...) less than 20 Volts (or alternatively a battery), discharged alkaline battery and a silicone bar.

Process:
Once the materials have been collected, open the discharged alkaline battery (if it is not discharged, burns may occur), avoiding contact between the skin and its contents. Remove the graphite bar that is in the center with a clamp. Wash it, and clean it with sandpaper.
Regarding the bottle, make a hole in the lower side, the size of the graphite bar. Introduce the graphite rod through the hole and stick it with hot silicone. Prepare a saline solution with 3 tablespoons of salt in a liter of water, and pour it into the bottle, checking that there are no leaks through the hole made.
To start the production of Sodium Hypochlorite, the positive transformer cable must be connected to the graphite bar. And the negative cable must be devoid of its insulating wrapping and introduced into the solution from the top hole of the bottle. Connect the transformer. If the cables are incorrectly connected, a brown color will be seen on the upper cable. Reverse the polarities and prepare the saline solution again. Place it in a ventilated place. Wait 1 hour. Disconnect the transformer. Filter if necessary with any clean cloth. Pack the obtained hypochlorite.
An example of the assembly:

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If you are in an emergency, and there is no drinking water or hypochlorite, do not hesitate to use any source of power, seawater and a pencil (contains graphite) to prepare the hypochlorite, and you can disinfect any water, for this apply the hypochlorite until it acquires a MILD smell and taste of chlorine.
Regards!!!

References:

-Mortimer, Charles (1983) Ed. Iberoamérica

-Thomas Derry y Trevor Williams (1977) Historia de la tecnología 3: 1750 – 1900. Madrid, España. Siglo veintiuno de España editores.

-Stamboullian, Rossotti, Fridmann, Luchetti y Cheade (2011)
Eficacia de cinco desinfectantes para la reducción bacteriana doméstica. Buenos Aires, Argentina.