Commercial washing powder surfactants v NaHCO₃

[Erina]

I have been relying on washing my clothes with bicarbonate of soda and white vinegar (separately) for a few years now, and wondering now if it’s actually leaving my clothes as clean as I thought ? I cannot send a sample off to a lab to be tested for bacterial growth, so I thought that I would go though Persil’s ingredients list to see what they were using and how they justified it, as well as how Bicarbonate of Soda and White Vinegar compares ?

I originally went this route to cut out all the man made chemicals that I didn’t understand. If I understand them better, I may well make my own washing powder, just with the least amount of chemicals to get the job done.

 

HOW I PRESENTLY DEFINE CLEAN

• No musty odour (bacteria)

 

HOW I PRESENTLY WASH MY CLOTHES

• Soak towels in a tub overnight in 10-14 litres of water, with 500ml of White Vinegar (Acetic Acid : 5%) @ pH 4-5

• Wash in a 40ºC cycle to rinse away the vinegar (already having achieved all it can in the tub overnight)

• Throw in 2tbsp of Bicarbonate of Soda into a second 40ºC cycle

• Dry on a radiator in one day, or line-drying

 

WHAT I WOULD LIKE TO KNOW

• Assess whether the clothes contain Bacteria or Fungi which is acidphile, neutrophile or alkophile in order to know how to treat them

• How to destroy Bacteria / Fungi with the least amount of chemical compounds and not leave them dormant

• Soap (sodium hydroxide and potassium hydroxide) breaks the cell walls of bacteria, can bicarbonate of soda emulate that, or come close ?

 

WHAT I ALREADY HAVE A BASIC UNDERSTANDING OF

• The NHS recommends washing clothes at 60ºC to kill bacteria, but 90ºC leaves no stone unturned. However, only cottons can take that temperature, so I need a chemical solution

• White Vinegar (Acetic Acid : ~5%) may not be enough to kill bacteria and could even be a food source for them, leaving them dormant (whilst soaking, separately from the bicarb)

• Soaps and detergents contain strong surfactants which are much better at destroying the lipid bilayers of Bacteria

• A virus has no metabolism so it cannot produce smell, the smell is Bacteria e.g. from a towel

 

Now I know that bicarbonate on it’s own cannot compete, but how much better is a commercial option versus a far more basic compound in a 60ºC wash ?

 

PERSIL : SURFACANTS

• C12-15 Pareth-7 : An ingredient which helps to clean or remove dirt and oil, creating foam when used with water

• MEA-Hydrogenated Cocoate : An ingredient which helps to clean or remove dirt and oil, creating foam when used with water

• MEA-Dodecylbenzenesulfonate : An ingredient which helps to clean or remove dirt and oil, creating foam when used with water

• Sodium Lauryl Sulfate : An ingredient which helps to clean or remove dirt and oil, creating foam when used with water

 

ref : https://www.unilever.co.uk/wiop/products/persil/persil-3in1-biological-detergent-capsules.html

 

How does Sodium Bicarbonate compare with the above surfacants ?

[studiot]

Bicarbonate of soda is actually a mild acid (in solution).

Acids do not deal with fat/grease.

That is what surfactants (posh name for soaps) are for.

If you do not wish to use chemical prdoducts you might try soaps nuts from the soap nut tree.

My family have found them to be quite effective even in cold water (which is how they are traditionally used).

https://en.wikipedia.org/wiki/Sapindus

We have also found them cheaper than commercial chemicals, and easily available in the UK.

[chenbeier]

 

28 minutes ago, studiot said:

Bicarbonate of soda is actually a mild acid (in solution).

 

No its alkaline compound pH 10 -11

[studiot]

33 minutes ago, chenbeier said:

 

No its alkaline compound pH 10 -11

Yes you are right. Thank you for the correction.

Bicarbonate of soda is amphoteric and depends upon temperature and other compounds in solution.

So with just cold water it has a ph of around 8 point something.

[chenbeier]

@Erina , Alkalinity is not enough to have good Washington results. You need surfactant, add Butter, Raps oil to the Soda and boiling the solution.

[Erina]

I found that in 14 litres of tap water 4tbsp of bicarbonate of soda will remain stable at pH8.

@studiot : I read bad reviews on the soaps nuts, perhaps they need to be incorporated into a soap mix rather than thrown into the washing machine ?

@chenbeier : What kind of Butter, Almond Butter ? Rapeseed Oil left me a little uneasy after reading how it is made : https://www.smartholistics.co.uk/news-blog/the-dark-side-of-rapeseed-oil/

I've seen recipes online calling for three main ingredients:

• NaHCO₃

• Soap : https://www.thesoapery.co.uk/collections/melt-and-pour-soap-bases/products/castile-liquid-soap-base-organic

• Borax (Sodium Tetraborate : boron, sodium, and oxygen)

 

The soap I am most comfortable with is from the Castle brand, which contains Aqua, Potassium Oleate, Potassium Cocoate, Glycerin, Potassium Citrate, Citric Acid.

I think I’ll skip the Borax as it cannot be ingested (even though it can apparently be used for toothpaste?!) and just go with Bicarb and the Castle soap.

 

TOTAL INGREDIENT LIST

• NaHCO₃

• Aqua

• Potassium Oleate

• Potassium Cocoate

• Glycerin

• Potassium Citrate

• Citric Acid

 

That’s a lot of changes ! How does that compare to Persil now ?

 

• Potassium Oleate : an emulsifier/surfactant to prevent separation.

• Potassium Cocoate : a natural surfactant, which spreads molecules apart to reduce surface tension and release trapped dirt and grease.

• Glycerin : a humectant to allow the skin to breathe and not dry out.

• Potassium Citrate : I cannot be sure, it’s either a fire suppressant or the same thing as Citric Acid ?!

• Citric Acid : balancing agent and preservative.

 

nb. Chemical company Triveni Interchem reports that dead bodies of bees and Pogonomyrmex ants emit potassium oleate as they decay. Other insects respond to the smell of this chemical by removing the body of the dead insect from the nest or hive. If you brush the body of a live bee or ant with oleic acid, other insects will remove it from the hive or nest as if it were dead.

 

ref : https://healthfully.com/side-effects-of-sodium-carbonate-6166685.html

 

This isn’t too bad of a list, and I shall try it without the Borax, what do you think ?

 

I also found some Shea Butter for a decent price, but I don’t think that I need it with the Castle Soap : https://www.amazon.co.uk/Shea-Butter-1kg-Refined-Natural/dp/B07G2J7758/ref=sr_1_7?dchild=1&keywords=the+soapery+butter&qid=1628710353&sr=8-7

I would like to add some fragrance, in the form of an essential oil, but being volatile there's not much point.

Edited August 11, 2021 by Erina

[chenbeier]

chenbeier :What kind of Butter, Almond Butter ? Rapeseed Oil left me a little uneasy after reading how it is made : https://www.smartholistics.co.uk/news-blog/the-dark-side-of-rapeseed-oil/

 

I mean normal butter made from milk from cow what you put on a bread. Also magarine is possible. Instead of the raps seed oil every oil made from plant is ok, so you found already oleate, made from olive oil or cocoate  made  from  coconate oil. You can also melt candle wax mix with Soda.

[John Cuthber]

The idea of a "surfactant" is interesting.

One of the oldest is soap.

And that's the sodium salts of fatty acids.
But part of the residue left on clothing is a mixture of fatty acids- the lower molecular weight ones are responsible for part of the bad odour.
So adding dirty clothes to a weak alkali like bicarbonate will generate a very small amount of soap.

And it will also remove some of the material that's responsible for the smell of stale sweat.

Hypothetically, the stuff will also hydrolyse fats but that reaction is very slow.
To make soap, you normally use a fairly concentrated solution of sodium hydroxide and heat it to nearly boiling so it's about a hundred million times more alkaline and also hotter.

Fundamentally, washing soda is cheaper and more alkaline.

Hence the name...

Drying kills most bacteria.
If they didn't kill you when you wore the shirt, they probably won't kill you after they got washed off and then dried.
 

One valuable reason to add glycerine to soap is that it absorbs water- which is marvelously cheap.

Also, if you make soap, the by-product is glycerine.

So you can save yourself the trouble of removing it by leaving it in the soap, and calling it an ingredient.

It's very soluble in water so it will rinse off at least as easily as the soap. There won't be any left on your skin.

The water you wash it off with is actually quite good at hydrating; glycerine, on the other hand, is a dehydrating agent.

Edited August 11, 2021 by John Cuthber

[exchemist]

I'm a little confused by this discussion. I always thought that washing soda was Na2CO3, sodium carbonate, rather than  NaHCO3, sodium bicarbonate.

That would be a stronger alkali than bicarbonate and presumably more effective at reacting with fatty acids or even saponifying fatty material.  

 

 

[John Cuthber]

5 minutes ago, exchemist said:

I'm a little confused by this discussion. I always thought that washing soda was Na2CO3, sodium carbonate, rather than  NaHCO3, sodium bicarbonate.

That would be a stronger alkali than bicarbonate and presumably more effective at reacting with fatty acids or even saponifying fatty material.  

 

 

Yes it is. It's generally a better cleaning agent than the bicarbonate.

And it's cheaper.
 

[Erina]

So it's settled, I don't need to concern myself with Sodium Tetraborate (Boron, Sodium, and Oxygen) and can, at first, focus on the soap's ingredients, along with the Sodium Bicarbonate.

I used to heat NaHCO3 in the oven to >200ºC, which would make it a lot lighter, as it would dissolve in water better, was that Na2CO3 ?

I did it because I used to live in a hard water area, but could never be sure if it really did the job better, and when I moved, it was an extra step I just stopped.

What would the Sodium Bicarbonate do in tandem with the soap in the wash that the soap itself could not do, what is its function ?

[exchemist]

4 hours ago, Erina said:

So it's settled, I don't need to concern myself with Sodium Tetraborate (Boron, Sodium, and Oxygen) and can, at first, focus on the soap's ingredients, along with the Sodium Bicarbonate.

I used to heat NaHCO3 in the oven to >200ºC, which would make it a lot lighter, as it would dissolve in water better, was that Na2CO3 ?

I did it because I used to live in a hard water area, but could never be sure if it really did the job better, and when I moved, it was an extra step I just stopped.

What would the Sodium Bicarbonate do in tandem with the soap in the wash that the soap itself could not do, what is its function ?

If you heat NaHCO3 to 200C you will indeed decompose it to Na2CO3: 2 NaHCO3 -> Na2CO3 + H2O + CO2. You have effectively been making ordinary washing soda by a rather wasteful and expensive route. Since washing soda will do a better job than baking soda (sodium bicarbonate), why not just buy that instead?  

 

 

 

 

[Erina]

I like to experiment. I had it on hand so I tried and and just didn't think anything of it, ordering it time after time. Besides, it was all-bills-included at that place anyway.

I checked the prices and they're the same, so I think it's a good idea. However, what does it do to complement the soap, with the ingredients listed above regarding washing clothes ?

[exchemist]

20 minutes ago, Erina said:

I like to experiment. I had it on hand so I tried and and just didn't think anything of it, ordering it time after time. Besides, it was all-bills-included at that place anyway.

I checked the prices and they're the same, so I think it's a good idea. However, what does it do to complement the soap, with the ingredients listed above regarding washing clothes ?

Washing soda will have some ability to saponify fats, whereas soap simply emulsifies them. Strong alkalis are often useful in the kitchen at cleaning fats that have degraded and become sticky and resistant to detergents. Oven cleaners are a good example. I'm not sure of the chemistry of these degraded fats (maybe someone else here will know), but it seems that alkalis can still saponify them. Washing soda is not as strong as caustic soda for that (and by the same token is considerably safer to use), but probably quite a bit better than bicarbonate, I would think.

[John Cuthber]

What's wrong with using soap?

I realise it's rather old fashioned- Roman technology- but it works and it's cheap.

[exchemist]

As an addendum, when I was on holiday in Tiree last week, staying with a rather back-to-nature niece, she washed some clothes using "soap nuts", a sort of brown nuggets that she put in the machine in a little bag along with the washing. I had never heard of these. It turns out these contain saponin, a triterpene glycoside which, having an oleophilic and a hydrophilic end, is a natural surfactant and has been used for centuries in the Indian subcontinent. Soap nuts come from the soapberry plant, Sapindus.

The clothes seemed to be clean and odour-free after washing, though obviously as the soap nuts remained in contact with the clothes until then end, there was not much effective rinsing off of the saponin. (Possibly the lower temperature at the end of the rinse cycle will have reduced the amount leaching from the nuts.) Be that as it may, I have not developed any rashes or skin irritation, so it seems to work fine.    

[Erina]

I read discouraging views about the soap nuts.

Interesting.

Edited September 8, 2021 by Erina