I’m not enough of a chemist to give a quantitative answer without a lot of reading, but I’m guessing by the time you’ve reduced the Sodium from the hydroxide, that you will have spent more energy than it would take to produce the hydrogen electrolytically. If you do produce the metallic Sodium, you want to be very, very careful when you add water to get your hydrogen, since you get a LOT of heat in the process. You pay for that heat when you reduce the Sodium. I could be wrong—I have a long history in that area (being wrong, not chemistry ).
NaOH is electrolyzed to produce hydrogen which is done commercially for both hydrogen and sodium hypochlorite (bleach).
The other way is to use the NaOH is to use it as a catalyst to react zinc or aluminum with water. It produces a LOT of heat and careful control of the reaction. I don’t know if you can use this to separate the metals or not.
Apparently silicon also works as a leftover from the silicon industry, but I don’t know if you can use say crushed ICs or not. It forms sodium silicone dioxide which is used in the glass industry. and I didn’t read the full research paper.
But I agree in general principle that is probably isn’t very viable unless you have a use for the “by-products”.
I think he was taking about metallic sodium and water to produce hydrogen, which will certainly work. I don’'t remember how you get the metallic sodium out of a water solution. Maybe you do it using molten NaOH, another exciting process. Here’s a video of the sodium-water reaction:
I’m thinking that scaling this up may not be a great idea. I remember my uncle telling be about a friend of his that liberated a chunk of sodium from a chem lab at school, and tossed it in a neighbor’s swimming pool. Cracked the pool.
Sean, its the other way around. Sodium cloride solution is electrolised comercialy to form hydrogen, clorine, bleach and NaOH.
I visited a factory here once that does this on a large scale. They still use the old technic where the cathode is Mercury and sodium disolves in it, where it can then be reacted with water to produce NaOH. What surpriced me most is that they dont use the hydrogen. It was all burnt up in a flare on top of a smoke stack. I shuld have pictures somewhere, the flame is like nothing l ever seen. Apears white, transparent… like a ghost. Probably has some nasty trace elements in…
If a solution of NaOH is electrolised the only byproduct are O2 and H2 with NaOH being just the electrolite. But Kent is right, sodium is produced by electrolising molten NaOH. I tryed this once. Nasty stuff. Its hot, super corrosive, eats glass in seconds, and its dependant on temperature. It needs to be kept at barely melting point or the sodium disolves in the hydroxide. The byproduct of the reaction is H2O and occasionaly a bubble of molten sodium metal will wonder to the anode where H2O is produced and you guess how this ends. BOOM. Spitting molten NaOH everywhere.
You are right. If you use an aqueous solution, the NaOH acts more like catalyst, and it produces h2 and o2 with electrolysis, when the excess water in the solution is gone then the sodium collects at the cathode.