A fair bit of the "ecleaningmag" article is okay and factual given its focus on using KOH or NaOH solutions for cleaning greasy surfaces.
I find this statement is truly off the wall, however --
"....
At the molecular level, potassium hydroxide is also slightly smaller than sodium hydroxide; therefore, it can penetrate oil molecules faster than sodium hydroxide, thus breaking the oil’s hold on surfaces quicker. ..."
When you use KOH or NaOH for making soap or cleaning greasy stuff, it's not the MOLECULE that is doing the cleaning. In water, these alkalis dissociate (break apart) into OH ions and K or Na ions. If you look at the size of the ions, the K (potassium) ion is larger than an Na ion, so the author's belief that it's smaller and thus can clean better makes no sense.
As far as the soaper using KOH and NaOH in her soap, yeah,
it's a legitimate thing one can do. Back in the day when people made lye from ashes of wood and other plants, the soap was a mixed potassium and sodium soap, and I'm sure this mixed alkali soap cleaned as well as our pure sodium soap or pure potassium soaps do.
KOH makes soap more soluble in water, which is why it can be helpful if included in bar soap recipes that are (a) high in stearic or palmitic acids (high lard, palm, butters) or (b) high in oleic acid (high olive oil and other HO oils). Adding KOH will not greatly affect the solubility of a soap that's already highly water soluble -- a 100% coconut oil soap is a perfect example.
I have no idea why the soap maker cites the article as justification for making a dual lye soap -- they don't seem to be related. Also a 60:40 ratio of NaOH:KOH is going to make a fairly soft bar soap. That ratio is more typical of a shave soap/croap recipe that's supposed to have a softer paste texture than a bar soap that should be firm. Maybe she's wanting a softer soap, however.
But if you want a physically harder bar soap, you can get very nice results with just 5% to 10% KOH. At 5%, which is what I use routinely, the hardness of the bar isn't affected. One benefit of using a bit of KOH is you can reduce the coconut oil in the recipe, and still get a soap that lathers beautifully.
The addition of 2% citric acid is not helping the cleaning ability exactly. The citrate formed by adding the citric acid to soap is a
chelator. A chelator will help reduce soap scum, making the soap more effective.
But if the soap maker is not also adding the additional alkali that will be consumed by the citric acid, she's also increasing the superfat in this soap. Higher superfat will reduce the cleaning effectiveness of a soap.
