Sciencemadness Discussion Board

Potassium carbonate from banana skins

Random - 26-6-2011 at 16:38

I read on few pages that average banana contains about 460 miligrams of potassium while the skin of those bananas contains 40% of that potassium. That is about 180 mg of potassium per skin.

Since there are threads about isolation of potassium carbonate from wood ashes, I think it's better to isolate it from first dried and then burned banana skins. Ten banana skins on average would yield 1,5-2 grams of potassium, but if it's just potassium ion, there would be actually more by weight of potassium carbonate. That is a lot more than K2CO3 from wood ashes, as some people have extracted few kilos of wood ashes to get very small amount of it.

What do others think about that, is it better to isolate is from burned banana skins or wood ashes? Maybe I will perform an experiment with that and show the results.

m1tanker78 - 26-6-2011 at 17:59

In terms of availability, wood ashes are abound [almost] anywhere. In contrast, 'naners might be seasonal or even rare for some. Extracting the potassium salt from banana peels would still be messy IMO.

On the other hand, it would be interesting to confirm roughly what proportion of elements (Na, K, Mg, etc)+ are present in a typical banana. It will depend on the local soil and (probably) the species.

Tank

bbartlog - 26-6-2011 at 19:09

Sounds promising at least to the extent that your ashes should be highly enriched in potassium. Which approach is better depends on your resources and goals, of course...

LanthanumK - 27-6-2011 at 02:55

It depends on which one is more accessible for you. For me it would be banana skins.

ScienceSquirrel - 27-6-2011 at 04:20

Quote: Originally posted by LanthanumK  
It depends on which one is more accessible for you. For me it would be banana skins.


Just how many chimps do you have out back? :)

LanthanumK - 27-6-2011 at 04:48

None, only humans who act like chimps.
If I wanted to synthesize K2CO3, I would start with 1 banana skin, not 100. Cero fireplaces make no ash.

theflickkk - 27-6-2011 at 05:37

Hmm i did try this out before but I never really calculated the yields. I remember burning 5 peels till they turned to ash then washing the ash with some distilled water. The filtrate did leave some white stains on the side of the beaker when it was evaporated. Never tried this again since potash can be bought at the pottery store for cheap. I could give this a go again though. Since bananas are really cheap and tasty so why not lol

The WiZard is In - 27-6-2011 at 08:51

Quote: Originally posted by Random  
I read on few pages that average banana contains about 460 miligrams of potassium while the skin of those bananas contains 40% of that potassium. That is about 180 mg of potassium per skin.e I will perform an experiment with that and show the results.


When done with this here dobe several other ideas.


Potassium carbonate was formerly manufactured almost entirely
from wood ashes. The ashes were treated with water, filtered, and
the solution evaporated. Nowadays, in addition to the above
source, most of the " potash " of commerce is obtained from three
sources: (a) from beet-root, (b) from the sweat of sheep, and
(c) from potassium sulfate. (a) The molasses from beet-root sugar
is allowed to ferment, and is then evaporated. A black mass
containing the potash is then obtained. (b) One-third of the weight
of the sweat of sheep is potassium compounds. The washings of
sheep wool are evaporated to dryness, and then heated in retorts.
What is left is carbon and various potassium salts, which are then
separated. (c) Potassium sulfate is obtained as a byproduct in
many processes. It is converted to the carbonate by a process
noted later under the manufacture of sodium carbonate.

An elementary experimental chemistry
By John Bernard Ekeley
1900
Google.com/books

See also

MANUFACTURE OF POTASSIUM SALTS
FROM SUINT. [Suint is French for sheep sweat.]
BY WILHKLM BOTT, PH.D.
Journal of the Society of Chemical Industry, Volume 2
1883

Scapegrace - 2-3-2012 at 07:37

after you would burn it though how would you get the K from all the ashes?

Pulverulescent - 2-3-2012 at 07:47

He'll get its carbonate from the ash ─ I once saved my cigarette (cough!) ash for a few days, as an exercise, dumped it in water, filtered and evaporated to crystallise!
I got quite a bit more (mixed?) carbonate than I'd expected . . .

Scapegrace - 2-3-2012 at 07:55

so if ou mix it with water then evaperate it after draining you would have potasium?

Neil - 2-3-2012 at 09:15

@ Pul,

Not to mention the bonus K you got from the KNO3 added to even out the tobaccos burn

AirCowPeaCock - 2-3-2012 at 09:43

Yumm

White Yeti - 3-3-2012 at 15:17

If I had banana skins, I would definitely try it. Wood ashes is a real mess and the yields are ridiculous.

Wood is more available for me, but I'll try bananas and post results if I get any.

unionised - 4-3-2012 at 02:21

Just a thought. There may be other merits to this experiment.
http://www.straightdope.com/columns/read/2389/will-smoking-b...

bbartlog - 4-3-2012 at 11:46

Quote: Originally posted by White Yeti  
Wood ashes is a real mess and the yields are ridiculous.


Eh, but then wood will burn to ashes all on its own while banana skins may not. Anyway, sure, banana skins will get you ashes highly enriched in potassium compounds... but to me it sounds easier to put a kilo or two of wood ashes in a bucket and leach them than to obtain 100g of banana skin ashes, even if the latter might have a similar quantity of potassium salts.

White Yeti - 4-3-2012 at 12:09

Quote:
Eh, but then wood will burn to ashes all on its own while banana skins may not.


If you know anything about building fires, wood will most certainly does not burn on its own. It takes a while to get logs to start burning. For your entertainment and information, banana skins will burn.
Quote:
but to me it sounds easier to put a kilo or two of wood ashes in a bucket and leach them than to obtain 100g of banana skin ashes.


Ahem, have you tried leeching potassium carbonate from wood ashes? I can assure you that it's easier said than done. I assure you that burning banana skins sounds like a better alternative, even if I'd have to wait a few months to get enough banana peels.

Besides, I'm not in a hurry:)

m1tanker78 - 4-3-2012 at 17:05

Quote: Originally posted by White Yeti  
I assure you that burning banana skins sounds like a better alternative, even if I'd have to wait a few months to get enough banana peels.


Composting 101?! :)

Banana trees grow like weeds around here. I wonder how much K is in the stalks and leaves. I know, mostly water when freshly cut but if left to dry in the sun a few days then calcined...? (for curiosity's sake)

Tank

bbartlog - 4-3-2012 at 17:36

Quote: Originally posted by White Yeti  

Ahem, have you tried leeching potassium carbonate from wood ashes? I can assure you that it's easier said than done.


Indeed I have; I even posted my experience here: http://www.sciencemadness.org/talk/viewthread.php?tid=13527&...

I agree it's a pain (though it doesn't need to be quite as difficult as I made it on my first try), but the banana skin ashes would still require performance of a lot of the steps I did, just on a smaller scale.

Vikascoder - 13-3-2012 at 04:00

how much potassium carbonate is obtained from 1kg of wood ash

White Yeti - 13-3-2012 at 10:47

Quote: Originally posted by Vikascoder  
how much potassium carbonate is obtained from 1kg of wood ash


When I did it, I got a solution that was so dilute I didn't bother evaporating the water.

I'd say about a gram or so, if not less.

bbartlog - 13-3-2012 at 11:42

Quote: Originally posted by Vikascoder  
how much potassium carbonate is obtained from 1kg of wood ash


It varies depending on the source material. Hardwood ash is actually significantly poorer in potassium than that obtained by burning leafier or succulent plants. However, it's still about 4% K2CO3 (or KOH) by weight.
If you read my attempt (linked to above) I only got 106g of K2CO3 from 15kg of wood ashes, i.e. less than 1%. However, I experienced avoidable losses (or sacrificed yield) at numerous points along the way. If I were to do the experiment again I expect I could get 2%.

jpneubert81 - 24-6-2012 at 15:19

This may help answer some questions.

http://pdfcast.org/pdf/chemical-composition-of-musa-sapientu...

I've got one question though, any real reason to extract the K from the banana peels? If you are like me I'm assuming it's for a home garden or something similar.

Any ice cream shop (banana splits) or fruit smoothie bar would probably be glad to collect a reasonable amount of peels for you if you are looking for larger amounts of peels.

My suggestion is to dry them first, flat on a piece of cardboard in a hot garage during the summer works well. Next a simple (relatively cheap) smoker box from any store selling grilling supplies should work. Start a fire on your grill and load the box w/ peels and wait.

Here's what I do different though. I use distilled vinegar on the ashes to make KCH3COO then filter the ash. Potassium Acetate is a great foliar feed on veggie plants.

elementcollector1 - 19-12-2012 at 16:48

What about grass clippings, how much potassium/sodium content do they contain?

triplepoint - 20-12-2012 at 08:22

Quote: Originally posted by elementcollector1  
What about grass clippings, how much potassium/sodium content do they contain?


A study, linked below, conducted for biofuel purposes, found that the ash content (basically total minerals) in various types of grasses varied from about 1%-10%. Switchgrass, in specific, was found to contain 5580 ppm of potassium by dry weight when fresh. The longer it lays around, the more potassium leaches out.

http://ncsungrant.sdstate.org/uploads/publications/SGINC1-07...

elementcollector1 - 20-12-2012 at 11:48

Excellent! How do I find out which grass is kept in my lawn?

CrEaTiVePyroScience - 1-1-2013 at 06:30

Tried to extract potassium carbonate from banana peels. Well , it worked!
But I wouldn't say it's efficient , low yields and lots of work. Here is my video of the project, enjoy!

http://www.youtube.com/watch?v=NHDfGlJiFLI

~CPS

bbartlog - 1-1-2013 at 08:42

Well, OK. Decent video although I personally found the use of banana's (with apostrophe) rather than bananas (sans apostrophe) as the plural a bit grating.
However, I want to point out that the only reason you can have any confidence that what you have is (mostly) K2CO3 is because of prior work on plant ash. Although a decisive identification as K2CO3 would be a lot of work, you could at least do a few tests to confirm the idea rather than just say 'soluble white base, gotta be K2CO3'.
And I would expect that you have contamination in the form of a bit of KCl and K2SO4.

CrEaTiVePyroScience - 1-1-2013 at 11:00

Already did tests..
Did with Pb(NO3)2 and was almost no precipitate. Solution was a little bit cloudy but not much at all you could still look through it.
Anyhow, I will use the K2CO3 for KOH production so K2SO4 contaminations are a problem at all.

For KCl I honesty got no clue but I don't think it will be that high since I made KOH with ease. But might do some tests when I got time..

EDIT: It's about the science, chemistry not about spelling...
By the way , my native language isn't english.

[Edited on 1-1-2013 by CrEaTiVePyroScience]

Metacelsus - 1-1-2013 at 16:23

Quote: Originally posted by elementcollector1  
Excellent! How do I find out which grass is kept in my lawn?


It's probably some variety of Kentucky Bluegrass. Or, if your lawn is like mine, crabgrass.

violet sin - 16-6-2013 at 05:30

thought I would add my account of this experiment

had a little fun doing this. I eat banana's often so saved a big freezer bag full of dried peels. I chose not to waste time documenting my every move on the pilot run, just get a sense of the return. ash weight right after it cooled for a starting mass, and the mostly dry weight of the first wash crystals were recorded though.
I would guess it was 25-30 banana peels to start, but measured 25.60g of well roasted ash. they became damp overnight so I was glad it was weighed as soon as was possible. ash was washed with 2 x 50ml DW and maybe 20ml washing the filter down. it was a straw color when done so I added ~15ml H2O2 3% to improve color. filtered, reduced volume, hot filtered recryst again long story short 5.52g soluble basic salt dried to opaque off-white/white. there were still a couple chunks(very few) with a clearer look that must have had some moisture left.
I didn't check for chloride or sulfate contamination. I would guess almost 2g more in the 2nd 3rd washes combined with filters and crystalizing dish, but wasn't super important to get ALL of it this time.
25.60g ash begets >5.5g salts for me, I would say that is worth the time if you have access to banana peels. most were chiquita brand, few were organic, all were from safeway.


Poppy - 25-6-2013 at 11:25

Dry leaves and s**t usually contains often more potassium than calcium relatively to other plant parts. Ask your gardeners to follow up your idea and you can get a bust on that banana calcination of yours, as the leaves would help the peels make their way through fire!

Yeah potassium is relatively easy to be separated out...

And this would certainly collaborate not to make you obese :P

[Edited on 6-25-2013 by Poppy]

Fantasma4500 - 6-8-2013 at 10:09

does anybody have a list of the most potassium containing plants you can find around??

i remember this site which i recall as being of iranian origin..
they showed a list of different types of wood which contained ''0.2'' in general of potassium
not so interesting
then there was some other very interesting names i still remember..
''wormwood'' and thistles
thistles i recall as having around 7, isntead of 0.2 (measured by weight)
and wormwood somewhat around 8.5!!
wormwood is of what i found out not wood but rather a little plant which can be found at relatively dry places
bananas i dont see much reason in unless if you live in africa, the thing with potassium is that you want to make it BULK (the carbonate)
perhaps as part of the KNO3 'making' using ashes and dirt

in the old days farming places paid with potassium nitrate, the larger the farm was the more KNO3 they had to pay the government or well, it was probably the king of denmark back then, believe denmark owned it all

another thing i looked at is that potassium burns with a purple tint if relatively pure when held in a flame
thistles have a purple flower on them
PLAUSIBLY this could mean that theres a connection there for less common plants you might find around where you live?
it mentioned also that leaves and bark from trees had as much as 3 times more than the wood, leaves can be collected in shittonnes when the weather gets colder and its easy to turn into ashes (:
another thing would be 'guano' i believe its called
meaning ... shit from birds and bats also
this might be possible to collect in large amounts

again long back in time where blackpowder was really exciting KNO3 was made in the middle east by using gurana, in which apparently contains alot of potassium, to make potassium nitrate

i know i didnt state any mg / kg of dry plant ash, i dont recall it as even being there back when i read it, i found the bookmark tho, fryingcolors apparently, but the link is dead, approx +4 years old by now if not 5

violet sin - 6-8-2013 at 12:57

ya I have been saving up another batch as I'm outta town working again. lots of banana's eaten on breaks working construction. I was considering contacting a juice place to see if they would throw the peels off to the side for me. but this is just for $hits and giggles as it were. so no impetus to go full bore.

I also was reading on potassium nitrate the other day, and came across the thistle reference. I'm on lunch break so I'm not going to look for it now. the lady I am working for does all kinds of earthy things and grows kombucha and other cultures. she was interested to hear about the banana experiment. and offered this lill tid bit. the thistles being picked, may have been 2 birds with one stone type of thing. if the farmers had to clear them any way for the sheep, why go out of your way to pick a separate vegetation source ya know. they may have been just convenient, and worked enough for production. out by my family's ranches we have fields and FIELDS of pesky star thistle. if that could be turned into a cash crop, or at least subsidize its removal. could be very welcome news to those that hate the plants. knee-chest high everywhere you don't want em. enormous fire hazard in the dry foot hills where the summer gets to be in the hundreds often in summer. we have bailing machines for the alfalfa grown for cattle. could use those to round the stuff up. and burn when you weren't likely to take the entire country side with it. that is IF they were worth all the effort ya know. I'll have to try some or look for an online reference for the their combustion products. if one exists. that could be done in quite BULK quantities. hell farmers may even pay to have them removed. I'll read up on it as this kind of thing is fun to me.
-Violet Sin-

*edit: realized some of my statements weren't totally clear.
-the potassium nitrate was from potassium carbonate n animal urine IIRC. I know we are talking about the carbonate
-the lady I am working for does all the earth stuff because she is well educated in farming, homesteading and self sufficient living. as such she knows many antiquated farming techniques and practices pertaining to an older way of life.
- and finally specific plant I was talking about. http://en.wikipedia.org/wiki/Yellow_Starthistle "It currently dominates over 15,000,000 acres (61,000 km2) in California alone"

[Edited on 6-8-2013 by violet sin]

second editing:
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC396267/pdf/plntp...
guess the potassium is necessary for respiration in plants from the stomas. the guard cells that open or close are operated by potassium ion pump systems. so it is likely the potassium is higher in the leaves than the wood. but I haven't found any correlation yet about concentrations in fruit, seed or flowers. there may be special cases of accumulation for various functions there as well. my plant expert says potassium is used in photosynthesis, protein manufacture and respiration (stomas). he runs a high end garden shop for the last decade or so. trust worth in my opinion


[Edited on 7-8-2013 by violet sin]