Sciencemadness Discussion Board

Iodine from seaweed

rocketgunslinger - 28-7-2010 at 04:09

i was told iodine comes from seaweed, and can be extracted from said seaweed.if this is so, by witch method is this done?. A run down overview of said process would be a big help

[Edited on 7-28-10 by rocketgunslinger]

hissingnoise - 28-7-2010 at 04:40

http://www.practicalchemistry.org/experiments/extracting-iod...

From a quick google. . .

Picric-A - 28-7-2010 at 05:03

Dry 5Kg's of seaweed, grind it up to a fine powder. Mix the powder with about 1 litre of conc. sulphuric acid then distill off the iodine.
If your lucky you will get a useable amount of iodine from those quantities.

mr.crow - 28-7-2010 at 05:53

This was how Iodine was discovered by accident. http://www.mnwelldir.org/docs/history/iodine.htm

If you want to make your own iodine get some potasium iodide

ScienceSquirrel - 28-7-2010 at 06:43

Realistically you need large multikilo amounts of seaweed.
The weed should be hung in a shed to dry until it is bone dry and really crisp.
Fresh weed is best and weed that has been exposed to heavy rain will give lower yields.
At that point it can be burned to ash, the burning produces large amounts of fairly unpleasant smoke. Historically this was done on sea cliffs in Brittany when the offshore breeze provided good ventilation and blew the smoke out to sea!
It should be noted that ten kilos of wet weed will only weigh a kilo or so when dry and will produce only a few hundred grams of ash, so hauling lots of weed is a must!
The ash can then be digested with sulphuric acid and a suitable oxidising agent. The iodine can be distilled out or solvent extracted.

not_important - 28-7-2010 at 13:54

You do need to concentrate the salts and partially isolate the iodide, you can't use the dried but otherwise raw weed.

Burning is one route, another is extracting the partially dried weed with hot Na2CO3 solution, and acidifying to roughly neutral with H2SO4.

In either case the solution is concentrated to cause CaSO4, Na2SO4, and such to crystallise out; iodides are generally quite soluble and stay in solution. After that the solution istreated with further acid and an oxidiser, MnO2 often being used.

After the preliminary isolation of I2, you need to further purify it as it contains Cl and Br too. A portion of the I2 is converted to NA or K iodide, that mixed well with the rest of the I2, and the I2 sublimed from the mixture leaving Br and Cl behind as salts.

The iodine content of seaweed varies over a considerable range, both by species and location grown; brown typically has the highest content, red about half, greens about 1/10 that of browns. Typical numbers are Icelandic kelp, 8000ppm, Norwegian kelp 6000ppm, Atlantic kelp 2500-4000ppm, Pacific kelps 1000-1800ppm, Fucus spp. 200-500ppm, Wakame 50-150ppm, Sargassum 35ppm, and Nori 15 ppm. As 1000 ppm is 1 ppt or a tenth of a percent you'll need a lot of seaweed.

You can find references online, example is

http://www.liebertonline.com/doi/abs/10.1089%2Fthy.2004.14.8...

ScienceSquirrel - 28-7-2010 at 14:31

Quote: Originally posted by not_important  

Burning is one route, another is extracting the partially dried weed with hot Na2CO3 solution, and acidifying to roughly neutral with H2SO4.


I have had some experience with seaweed and adding water back to the most shrunken and dried out weed can result in it blowing back up to it's original size.
I have seen dried weed that looks crisp and insignificant on the shore turn in to a bank of what looks like almost fresh weed after a heavy summer storm.
The arithmetic is horrible; at a rough guess, 100kg of wet weed equals 10kg of dried weed that turns into 1kg of ash. Extract with water, neutralise with sulphuric acid and crystallise out the sodium sulphate. Boil to dryness, take the 100g of halide rich residual salt and distill with sulphuric acid and manganese dioxide to isolate maybe 4g of iodine if you are lucky.

densest - 28-7-2010 at 14:33

It's probably not practical... some beaches get covered with smelly decomposing seaweed & it's scooped up by the ton and carted off. You could probably get all you wanted & cheered for it if you showed up with a large truck and a pitchfork.

ScienceSquirrel - 5-8-2010 at 07:25

The BBC programme Coast recently covered the Brittany area.
About halfway through there is a practical demonstration of iodine from seaweed ash.
It will be available online for a month from the 5th of August 2010.

http://www.bbc.co.uk/programmes/b006mvlc

The WiZard is In - 5-8-2010 at 08:40

Quote: Originally posted by rocketgunslinger  
i was told iodine comes from seaweed, and can be extracted from said seaweed.if this is so, by witch method is this done?. A run down overview of said process would be a big help


Sure you just have to think big.

This from Thorpe — which see for complete details.
http://tinyurl.com/25cv7zv

The seaweeds chiefly used in Japan for the extraction of iodine ar e
Laminaria sp., Ecklonia cam, E. bicyclis (Kjellm.), and Sargassnm
sp. The iodine content varies with the age of the algae and also
with the time of year, being greatest during June to September ;
the following figures give the iodine content of some of the raw
seaweeds : Ecklonia cava, 0.23 p.c. ; E. bicyclis, 0.27 p.c.;
Sargassnm sp., 0.05 p.c. ; Laminaria angustata (Kjellm.), 0.18
p.c.; L. lonqimima, 0.17 p.c. ; L. ocholensis, 0.19 p.c.

Trivia on an industrial scale - how do they melt iodine.

The WiZard is In - 5-8-2010 at 08:57

Quote: Originally posted by rocketgunslinger  
i was told iodine comes from seaweed, and can be extracted from said seaweed.if this is so, by witch method is this done?. A run down overview of said process would be a big help


For the truly driven I recommend (not found @ Google books and I am not tempted to scan it) —

James Hendrick
The Value of Seaweed as Raw Material for Chemical Industry.
Journal of the Society of Chemical Industry 35 [10] 565-574, 1916.
[Incorrectly sited in Thorpe as 35 [13].]

mr.crow - 5-8-2010 at 10:03

"Not available in your area" FFFFFFUUUUUUU

Now I have to find a proxy just to watch a video about seaweed

Sedit - 5-8-2010 at 17:29

I hear talk of the unpleasent smell of the iodine but could this be performed in a kiln on a large scale that would destroy the nastys without destroying the iodide present?

What are the nasty smells produced composed of? I have fair access to seaweed and various kelps and this is one experiement I always wanted to try to just browny points if nothing else.

mr.crow - 5-8-2010 at 18:37

You can use 92.48.88.210 port 7743 as a proxy server for now. These things come and go

I know KI can be oxidized by air so I would rule out heat.

EDIT: In the video they use dry burned seaweed so its probably ok. And they get brown water with purple gas.

Iodine smells nice :)

[Edited on 6-8-2010 by mr.crow]

Sedit - 5-8-2010 at 19:08

I was thinking more along the lines of soaking the kelp or sea weed in CaOH and placing it in a kiln after it dries and collecting the salts that form which will more then likely be vitrified if I allow the heat to rise to much.

What about algae? is there any in the sea that concentrate iodides?

Contrabasso - 5-8-2010 at 23:03

First you need a real life estimate of the iodine content of seaweed, I'm GUESSING that it's possibly 0.01% of the dried mass, you must find a better figure by experiment or from literature.

You then have to find a way of handling ton size batches (whichever Ton/Tonne!) - that is a lot of shovelling!
Then it's your choice whether you adopt a wet method of macerate and ion exchange -which needs a lot of resin to move a ton in solvent! Or you could try a dry process of burning off the organics to leave all the inorganic solids. However that would mean most of a ton of smoke which would get you noticed, for all the wrong reasons.

Now if you could find an ion exchange resin that will absorb iodide while rejecting chloride, you could just pump sea water through for a month or two then recover some iodide in the elute.
Whether it's cheaper to find a source of a bag of KI .... but I expect it would be much cheaper to buy it at a known purity.

ScienceSquirrel - 6-8-2010 at 02:50

I think you could probably start with 5kgs of wet weed. Dry this by hanging it in a shed, You would end up with about 0.5kg, burn it carefully and collect the ash.
Boil with water and filter, collect the solution of salts, concentrate and add sulphuric acid and hydrogen peroxide.
This should yield about 0.5g of iodine, not a lot but a convincing demonstration and you woyuld have done some real old style chemistry! :)

Panache - 10-8-2010 at 00:59

if you are contemplating this because iodine is restricted for sale in your part of the world and you would like some, rather than wanting to perform the exercise in itself, you can purchase ground dried kelp for very little cost, try health food suppliers and look to purchase a 25kg sack. It will cost a similar amount to 500g in a health food outlet, around $25-100.

Contrabasso - 10-8-2010 at 23:58

And if the element is restricted in your home town, think carefully how much dried kelp you can have delivered before it gets noticed. If you have a thousand acres the answer is different from if you have a 20th floor apartment!

ScienceSquirrel - 11-8-2010 at 03:49

You might have a problem burning 25kg of dried kelp in a city as well.
This is a project for someone who has a few acres out back and neighbours they drive to see. :)
Might help if they keep hogs as well. Doubt they would notice the smell of the burning kelp over the smell of the hogs!

watson.fawkes - 11-8-2010 at 06:24

Quote: Originally posted by ScienceSquirrel  
You might have a problem burning 25kg of dried kelp in a city as well.
Those with a smell issue with this process might consider using a closed retort and treat the first stage as making charcoal, in other words, to use dry distillation. The fumes from this process can be condensed, led through a bubbler, and flared off. I am curious how much iodine would be in the seaweed-tar that's condensed from the out-gas. After making seaweed-charcoal, just burn it in open air as before to get at the inorganic salts. Burning charcoal shouldn't have much smell at all.

peach - 11-8-2010 at 18:15

Holy smoking sea snakes!

I think it'd be interesting to do this if only to demonstrate some old chemistry and appreciate what they had to put up with back in ye olde times.

But 5kg for 0.5g? :o I throw away more than that.

I think the major issue with ordering iodine is when it starts getting stupid (for the US) and it's very obviously on the way to a meth lab. 0.5g isn't making you a lot of meth.

I had a quick look at Erowid's meth synthesis, and it uses three times as much iodine as ephedrine, meaning 0.5g of iodine would produce a minuscule 0.167g of contraband. Checking KCI.org ("the anti-meth site"), that's about $13 worth. Again, according to Erowid, a hardcore meth muncher may go through a gram per day. Making that amount last all of around four hours for a hardened addicted.

That said, 0.5g isn't going to any major synthesis or illegal activity. If you only want 0.5g to do some sublimation, staining and what not, I'll post that. I have a 100g bottle of it in the post right now, and it's already sublimated to 99.5% purity for analytical work. I know it's a questionable reagent and I won't be posting grams+ out, but 0.5g is nothing (even chemically speaking). 0.5g would cost me about 5p, so the stamp will be ten times more than that. No 1 post cowboys of the night need inquire, however.

As far as seaweed is concerned, in Ireland (home of potatoes and mash, even though potatoes don't grow indigenously in the UK), they dry it, give it a quick fry and use it to add saltyness to things like mash. It's absolutely amazing, really nice. You'll see fried seaweed in Chinese places as well, I highly recommend it. I'd be tempted to say the Chinese invented that idea, but Ireland has it's own fair share of seaweed.That'd probably be a better use for it if you're not just doing it for the lolz but trying to produce usable, clean iodine.

Here are some more recipieZ for you, and these are the good kind, both from Ireland.

Champ = mash + spring onions, milk and butter
Colcannon = mash, kale or cabbage, butter, salt, and pepper, milk, cream, leeks, onions, chives, garlic, boiled ham or Irish bacon

FACT; the skin & surface layer of green potatoes is toxic

[Edited on 12-8-2010 by peach]

The WiZard is In - 13-8-2010 at 07:36

Quote: Originally posted by peach  

As far as seaweed is concerned, in Ireland (home of potatoes and mash, even though potatoes don't grow indigenously in the UK), they dry it, give it a quick fry and use it to add saltyness to things like mash.

FACT; the skin & surface layer of green potatoes is toxic.



even though potatoes don't grow indigenously in the UK

Curious construct, any way potatoes papa in Spanish
originated in Peru*.

Toxic?! Yup potatoes are member of the nightshade family
Solanum spp., other in the service of mankind include
food plants like the tomato, pepper, and eggplant, hallucino-
gens like thorn apple, mandrake, henbane, and belladonna, and
several garden ornamental like the petunia and perhaps the most common poisons plant of all - tobacco.

MRA Morgan & GR Fenwick
Foodborne Illness: Natural foodborne toxicants
The Lancet December, 15, 1990 pg. 1492-5

The potato glycoalkaloids are, perhaps, the most familiar natural toxicants
because of the scale of potato production (currently over 250 million tonnes
annually) and the common knowledge of the toxicity of green potatoes. Exposure
of potatoes to light (which causes this greening due to chorophyll synthesis,
unconnected to glycoalkaloid. accumulation) is one of many stresses, such as
fungal, mechanical, or insect damage, which together with sprouting lead to the
accumulation of high concentrations glycoalkaloids in the tuber. Although all
parts of the potato plant contain these compounds, the parts above ground are
richest (this is the reason for the toxicity of potato berries or apples). In the tuber,
the peel contains the highest concentrations, so that nonnal food preparation will
greatly reduce human exposure. Acute potato poisoning (eg, in Lewisham,
London, 20 years ago[11]) is almost invariably associated with consumption of
poor quality, damaged potatoes. In the Lewisham outbreak, 78 schoolchildren
were poisoned; 17 required hospital treatment. Neurological symptoms included
apathy, restlessness, drowsiness, and visual disturbance; the potatoes
contained glycoalkaloid levels in excess of 330 mg/kg and had pronounced
anticholinesterase activity. Commercial blemish-free tubers will generally contain
less than 100 mg/kg, and this level is very substantially reduced after peeling.
The recent finding that potato glycoalkaloids possess potent gut-permeabilising
activity may point to the possibility of chronic effects of dietary glycoalkaloids; 12
any such effects will be enhanced in individuals who regularly eat large amounts
of potato peel, for example, in the mistaken belief that this is a rich source of
vitamins and fibre. The hypothesis originally proposed in the early 1970s, that
potato glycoalkaloid consumption was associated with increased incidence of
spina bifida and anencephaly, seems now to have little support.

[11] McMillian M, Thompson JG. An outbreak of suspected solanine poisoning
in schoolboys. QJ Med 1979; 48:227-43

* Carlos M Ochoa
Los Solanum Tuberiferos Silvestres del Perú
(Secc. Tuberatium, Sub.-secc. Hyperbasrtbrum)
My copy complements of the International Potato Center
Lima Peru
Published 1962

See also —

Jernnifer A Woolfe
The Potato in the Human Diet
Cambridge University Press
1987



djh
----
Who has always wondered — What did the Italians
eat before Marco Polo brought spaghetti back from China and the
Spanish tomatoes from Mexico?



peach - 14-8-2010 at 12:26

The following has balls all to do with iodine, but I do have a jar of sublimated iodine and will send out 0.5g if you want some, and not a lot more. So I'm excusing myself for this ramble with that said.

When I'm not here, or bothering people on other fora, I do enjoy 'being a gay hippy', stroking plant leaves and noticing how they flow between species, families, genus and so on.

I will even admit to having hugged a tree, in private, in a forest. I decided the tree didn't want hugging after lightning began coming down and the wind blew it, causing it to go 'nnnn-reeeeek', as it was hugged. Then I replanted some of it's torn up roots.

I also hate 'hippies', and their woodstock field ruining, everyday lazy scum bag attitudes when the reality of tidying up comes home and they all go home.

But I have heard people going on about the nightshades, people who'll refuse to eat potatoes and tomatoes for that reason. There seems to be a strong cohesion between most of them and a very poor level of scientific knowledge.

I know there are certain root vegetables (literally roots), like potatoes of their locality basically, that grow in places like ?south? Africa or the ?Caribbean? (can't remember it's name now? Karva?), which is full of cyanogenic compounds that need cooking to obliteration prior to eating.

Then you have the old fruit stones, with similar things in them, used to knock fish out of streams.

I have eaten things with those compounds in. They're stored as inactive compounds in the plants to keep them out of it's own metabolism. Chewing them (killing the plant), as a cow or moronic human (me) does, bursts the cells and mixes the compounds with enzymes that catalyze the breakdown into more true to form, active cyanides. The effect is quite horrible; flushing, skin feels hot and dry, muscles aching, none stop stretching and wriggling around / writhing, a foul taste of soap, dry mouth, vomiting. Doesn't feel too bad after (I think small exposures actually assist the body in producing something). I'd take that over a New Year's hangover.

Certain 'edible' mushrooms fall into the same situation, just involving different toxins. Morels, the false kind, need a good cooking. I do begin to question how sensible it is to eat something when the mycologists picking them recommend winding down your car windows on the way home to avoid poisoning yourself with your, soon to be, dinner.

For you coke addicts out there, I believe the first synthesis (yielding a piss poor 1% or so of the product) actually came from atropine, which is in high concentrations in Atropa Belladonna. Atropean is the name of one of the three greek fates, who cut the spun threads representative a mans life, depicting his death. Belladonna, beautiful girl, as girls used to squash the berries in their fingers and rub the result in their eyes, causing their pupils to dilate (atropine drops are still used by ophthalmologists for this).

Then there's all that chat about witches flying on broomsticks and 'tripping' from Atropa. The story goes, they'd wrap broom handles with cloth soaked in it's extract, stick it in one of their numerous holes, and go. The flying on broomsticks being the result. Highly debated now and almost certainly incorrect. Shame those noobs eating that kind of shit (Datura) don't think about these things first, prior to dying.

I also have another planty tale. I think it was in Persia, back in the older than ye olde times, they used to make up big dye fixing baths, and use harmalan containing seeds in some part of the process. The tale goes that the stories of magic carpets arose from them all ending up slightly off their tits on the the monoamine oxidase inhibitor in the baths they were fixing the carpets in (which the region, now Iran, produces very ornate and bright variations on). The same may be true of people making fireworks with lithium carbonate, and subsequently getting it on their sandwiches (it's a very powerful mood stabilizer and anti-depressant, doubt that's needed when you spend all day setting off fireworks).

My last tale of deviation from the topic is not related so much to plants. The 'mad hatter' in Alice in Wonderland came about from olde England, when hatters would cure the felts of fine hattery with mercury, potentially causing them all to be a bit odd in the mainframe.

Even though I have a 100g of iodine sat on the kitchen counter now, I'm tempted to give the seaweed a go for the fun of it. I live in a porty, seagull ridden area, Arrrrr!, and have a fine supply o' greeny black gold. Going on the back burner, quite literally perhaps.
Quote:
Lord Percy: [removes lump of Green from pot] Oh, Edmund... can it be true? That I hold here, in my mortal hand, a nugget of purest Green?

Black adder: Yes indeed, Percy, except that it's not really a nugget but more of a splat.

Lord Percy: Yes, my Lord. A splat today, but tomorrow, who knows, or dares to dream...


[Edited on 14-8-2010 by peach]

The WiZard is In - 14-8-2010 at 12:49

Quote: Originally posted by peach  

I know there are certain root vegetables (literally roots), like potatoes of their locality basically, that grow in places like ?south? Africa or the ?Caribbean? (can't remember it's name now? Karva?), which is full of cyanogenic compounds that need cooking to obliteration prior to eating.


Cassava (Manihot esculenta), also called yuca or manioc, is a woody shrub of the Euphorbiaceae (spurge family) native to South America. ...

Wiki-P

Pretty close to tasteless unless cooked (boiled) in something.
However, nowhere near as tasteless as breadfruit, the British
brought it from the S. Pacific for their Caribbean slaves, who
refused to eat it!

Then plantain is not all that tasty and be careful with your pronunciation.

Speaking of psyco-d's, anybody still do nutmeg?

peach - 14-8-2010 at 13:17

Quote: Originally posted by The WiZard is In  

Speaking of psyco-d's, anybody still do nutmeg?


There are a number of newer posts by teens eating that on youtube.

The new shit in town is Jenkem

Never bothered with it (nutmeg) myself, it goes on my desserts, in the sauces or in the cupboard; & in the bin after it's been in the cupboard. It's also good in winter if you add it and cinnamon to coco.

Thanks for the reminder on the plant name, I don't like forgetting them.

Never heard of breadfruit before. But then, English cousine is basically everything we've stolen or pillaged from somewhere else blended and put on chips.

The WiZard is In - 14-8-2010 at 19:08

Quote: Originally posted by peach  


But I have heard people going on about the nightshades, people who'll refuse to eat potatoes and tomatoes for that reason. There seems to be a strong cohesion between most of them and a very poor level of scientific knowledge.



Goblin Market
Christina Rossetti 1859

Attachment: GOBLIN.DOC (65kB)
This file has been downloaded 1155 times

rundata - 19-8-2010 at 03:44

Quote: Originally posted by mr.crow  
You can use 92.48.88.210 port 7743 as a proxy server for now. These things come and go

I know KI can be oxidized by air so I would rule out heat.

EDIT: In the video they use dry burned seaweed so its probably ok. And they get brown water with purple gas.

Iodine smells nice :)

[Edited on 6-8-2010 by mr.crow]


Wow the cheek.

Did i give you permission to use my proxy server? no.
Did i give you permission to advertise it on public forums? no.

Access for public users is now disabled.

If you wish to use it ask.

[Edited on 19-8-2010 by rundata]