gatewood

1 hour ago, chenbeier said:

Yes, that is a common technical procedure to do electrolysis. Instead of a metal, also a Graphite Elektrode can be used.

If you have salt water NaCl, then on Anode chlorine gas and on cathod side hydrogen will be developed. Sodiumhydroxide will remain.

Yes for sure, but what I propose is minimal electronegativity, so it only becomes a sort of magnet for cations, without making an actual electrolysis reaction.

1 hour ago, SergUpstart said:

Graphite can be used as a material for the anode of the electrolyzer. The graphite anode is gradually destroyed during the electrolysis process, but it does not pass into the solution, but precipitates. And the membranes are made of cotton paper, although at present there are membranes made of polymer material that serve for a very long time.

A little more complicated, some of the chlorine will react with NaOH to form oxygen-containing chlorine salts, such as NaClO3

The cotton paper membranes... you mean the ones used to separate electrodes during the chloralkali process?

To my knowledge, that is totally false, it does go beyond the melting point, but not the boiling point because it doesn't even have a boiling point to begin with, it decomposes first:

https://www.google.com/search?client=-b-d&q=potassium+carbonate+decomposition+point

And sodium and calcium carbonates actually decompose bit more easily.

1 hour ago, exchemist said:

Where are the "locals", if I may ask? I have not read about many places with strongly alkaline soil. I suppose parts of the African Rift Valley would be one of them. But in most places where pH needs adjustment, it seems that the issue is the soil becoming too acid. 

 

 

Latinamerica. It is mostly as a result of poor understanding of agricultural practices. For example, some of the Xochimilco agricultural lands have been overfertilized or abused the use of slash and burn techniques to fertilize and lime their lands (leaving other lands acidic). Another, curious example happens in Brazil, there's been a surge in the use of biochar amending, which is a great practice in itself, but people don't understand that some woods contain a lot of lye (thus, some biochars should be treated with a bit of acid, before they're composted). It worked great for the oxisols of the jungles, but some places have started to become too basic.

Also, some volcanic regions with andisols have great, agricultural potential, though the soil must be acidified too.

Finally, acids are also a great way to treat pathogen/anaerobic ridden lands, it usually helps clear the stage for the return of healthy floras, upon which liming can be applied, to neutralize soils.

48 minutes ago, John Cuthber said:

Not to any meaningful extent.

The decomposition temperature is very high and there's a lot of CO2 in a fire which drives the reaction in the "wrong" direction."

 

The question does not arise.

You can make potassium hydroxide from the carbonate by reaction with slaked lime

54 minutes ago, chenbeier said:

But you need very high temperature to transfor to K2CO3 => K2O+ CO2

This KOH will be not clean from carbonate.

Better is to use electrolysis with a diaphragma.

The same way NaOH is produced.

I mentioned the burning process, because Ive been able to make potassium oxide using charcoal and coke furnaces (they can totally melt iron) which is more or less, the way portland cement is made, but you guys are definitely right.

I was thinking of improving the method, by simply separating the chamber that holds the potash, so it heats up by convection but does not let CO and CO2 in (with a small opening to vent off the decomposed CO2).

oh, haha.

But say, if I add a small current through it (not so much so as to electrify the water) to negatively charge it, will it become good at trapping cations?

I've been using potash as a cheap, very abundant basic chemical. I've also been aware that, if you burn it, you'll decompose the carbonates and get the even more basic potassium oxide.

I just wanna know: if I hydrate the potassium oxide (I know it can be dangerous), will I end up with potassium hydroxide?

I see, pretty new to the actual workings of ion exchange resins. What exactly do you mean with "chargesplus"?

31 minutes ago, John Cuthber said:

That's what I wondered about.
What you seem to be doing is making a crude vinegar as a source of acid by leaching plant material and then "fermenting" it to glucose, then ethanol, then acetic acid.
If you apply that directly to the soil, various bacteria will oxidise the acetic acid (to CO2) and you will essentially have added anything water soluble from the plant waste.
That's likely to include essentially potash and will make the soil alkaline rather than acid.

But I would have thought the cost of purifying the dilute acid was more than the cost of buying something like (NH₄)₂SO₄

 

Well no, if added to lye rich soils, it protonates them and it immediately decomposes and neutralizes the basic minerals (if sufficiently alkaline, the reaction will sometimes even be slightly noticeable). I mean, we're basically adding vinegar to the soil, and most of the alkaline metals in the biomass have already been taken up by the microorganisms that fermented it (ashes compose about 1% of the mass of wood).

We generally don't concentrate it, unless we previously produce it and then transport it to the site. I mentioned that we want to leave the locals with self-sufficient techniques and processes, if I'm inquiring for your knowledge, please, it is because I want to see what else is there to potentially try and experiment with, besides "look for it in the store".

Anyhow, the production of carboxylic acids have mostly phased out the use of acetic acid.

Some fungi and bacteria are capable of producing lignocellulosic biomass (like photosynthetic bacteria can produce sugars) just like plants, and I want to ask, if you know/think it is/might be possible to use them to generate large amounts of the product? To skip the growing of actual plants part.

Self-explanatory, can the conductive properties of graphite (or near graphitized charcoal/coke) be exploited to make ion exchange membranes?

6 hours ago, John Cuthber said:

What do you think the word "glacial" means in this context?

Concentrated acetic acid. Its made using freezing distillation.

3 hours ago, exchemist said:

Thanks for the information - very interesting to see how you have approached this. You have clearly gone to a lot of trouble.

I don't pretend to be expert on agricultural chemistry, unfortunately. Also, it's a little hard to know what would meet your needs, as you have not indicated any cost per tonne limit, where the sites of concern to you are in the world, or what materials you, or they, have to hand.  

However, shooting in the dark a bit, elemental sulphur and gypsum seem both to be used to reduce soil alkalinity. I also use FeSO4 in my garden (to grow calcifuge plants such as camellias), but I have no idea whether it is used on large scales. But you may already know this and have dismissed these for one reason or another. 

Bulk sulphur is quite cheap, being a byproduct of oil refinery desulphurisation of fuel. Current price seems to be < $100/mt in sacks, though it will be more by the time someone has shipped it to a useful destination.

 

P.S. Just found this, which discusses sulphur  - and FeSO4, so evidently that can have applications at the agricultural scale: https://www.canr.msu.edu/uploads/files/Lowering_Soil_pH_with_Sulfur.pdf 

Yes, this is exactly the concepts I'm looking for. I wasn't aware of the use of FeSO4, most appreciated input lad

I didn't provide an exact benchmark, because I'm looking for a broad range of ideas and concepts to explore (I've developed my methods myself), so it doesn't really matter to me how far off what you may propose, may be, I only look for you guys to share it (with the proper sources if possible)... if you would.

On 6/3/2021 at 1:08 AM, exchemist said:

I'm a bit mystified by all this. Surely the chloralkali process yields NaOH, not acid, doesn't it?

And when you speak of carboxylic acids, which ones are you talking about and what are you digesting anaerobically to produce them?  And what are you using mother of vinegar with, to convert it to acetic acid? 

Sorry for so many questions.

 

It does, but it also frees the chlorine and hydrogen gases, which I then react to make the hydrochloric acid, which can be rather dangerous (just added the comment, I long ago ceased to make HCl this way, though it may have some potential in farms close to the sea).

I make sugar using cellulolytic microorganisms to hydrolize cellulose (we usually get a lot of wood chips, since the projects use local wood to make structures). The resulting sugars are brewed to make ethanol, then the acetobacter are fed with the ethanol to make acetic acid. It may look like a lot of steps, but really, only big vessels are required to make the few batches needed, to ammend the soil (it does a better job at acidifying than composting the sugars).

Carboxylic acids, or more specifically, citric and gluconic acids, are produced using aspergillus nigger, which is also a cellulolytic fungus, meaning, it can feed on lignocellulosic biomass (though we aid it with a previous fermentation using trichoderma reesei), so a lot of cleared weeds, bushes and trees are the perfect feedstock for batch production.

Anyhow, do you people have any useful answers yet?

Yes, but I'm sometimes involved in projects that help poverty stricken areas, so our budget is limited. It'll be rather neat to leave the locals with knowledge that will make them self-sufficient (the carboxylic acid has done pretty well, but I want to see if I can do even better).

I've been engaged in agricultural practices for some time, and acids are particularly needed and useful products, to amend basic soils and lye rich biochars.

So far, I've managed to mass produce glacial acetic acid with mother of vinegar and carboxylic acids, using anaerobic decomposition. I've also made some hydrochloric acid, using the chloralkali process, but the table salt feedstock is not cost effective for the intended use.

So my question is this: do you know of any acids that are (relatively) easy and/or cheap to mass produce, without much need for expensive equipment and/or feedstocks?

Hmmm... I see, thanks for the input.

I've been scouring the web for some hours, looking for the temperature at which potassium carbonate decomposes into potassium oxide, but have had no luck (e.g. wikipedia only tells you that it will decompose before boiling, but not at which temperature this happens... argh).

This is the best I've found: https://www.sciencedirect.com/science/article/abs/pii/S0040603198002895

Does anyone know something about the matter?

2 hours ago, John Cuthber said:

Unless you are in a soft water area, you will spend a lot of time effort and money descaling the still if you don't deionise it.

https://water-research.net/index.php/water-treatment/tools/hard-water-hardness

According to this source, soda ash can form insoluble precipitates with calcium and magnesium ions. Oh boy, getting pretty easy to decontaminate water.

10 hours ago, John Cuthber said:

The use of a still to make pure water is well established.

But, if you live in a hard water area you may find it helpful to deionise the water first.

 

Also, have you considered reverse osmosis? 

The set-up costs are high but the maintenance cost is lower.

Yes, as I said, I know how to deionize water, but I'm trying to make an alternate process (as cheap as possible, trying to make just 5-10 L on each run) to produce something similar to deionized water without the ion exchange membranes. I suppose many post-filter volatilites can be eliminated simply by letting water boil for 5 or so minutes (with no distillation apparatus).

I'm looking for ways of making a cheap scale (doesn't need to be too precise) and I turned to vacuums to use as a countering force (or atmospheric pressure, to be more precise).

I'm thinking of simply sealing a syringe's barrel (the chamber) and then tying a little basket on the plunger (the tail), so I can weigh down the basket (with things I want to measure) and have the plunger move down to get a measurement.

What do you guys think? Is the principle practical for such purpose?

9 hours ago, chenbeier said:

It will work the same, but I dont think you get rid of the carbonate with this procedure. You need a good diaphragm, or do you use mercury electrodes, like the electrolysis of NaCl.

I use simple fabric as a separation membrane (though I think, that is only relevant when separating NaCl (or KCl, I suppose), to avoid making sodium chlorate) and conductive paint for electrodes (similar to using graphite).

It totally gets rid of the carbonate (turning it into CO2) for the soda ash (I think its a very well documented reaction), why wouldn't it for the pearl ash?

I've been producing some biodregradable hydrogels for some time and, one of the requisites for their manufacturing is deionized water (really, really pure water). Quality ion exchange resins can be a bit costly, so I learned how to regenerate them, though the process can be a bit problematic as well.

So I ended up turning to trying to make my own process of deionization (or as close as I can get to it) to simplify my work. So I came with the following process:

1. Pass tap water through an HEPA and activated carbon filters, to get rid of small particles and VOC (volatile organic compounds).

2. Shake the water pretty hard, to eliminate some disolved gases.

3. Boil it a little bit, to eliminate low boiling point volatilites and the rest of the disolved gases (at the cost of losing a little bit of water).

4. Distill the water (as close to 100°C as possible), to rid it of solubles and high boiling point volatilites (maybe use a fractionating column?).

Such process, I think, should eliminate all but the most exact of azeotropes from the water. What do you guys think?

I've been doing some electrolysis experiments with soda ash (sodium carbonate) to decarbonate it and synthesize sodium hydroxide.

Having recently extracted some pearl ash (potassium carbonate) from wood ash, I became curious in doing the same thing with it.

Will electrolysis of potassium carbonate yield potassium hydroxide?

Yes, that's what i thought. Thanks for the response.

I just watched this video:

Of some dude/gal making glycerine seemingly without a base/acid. It doesn't seem to me that he knows what he is doing, but maybe he does, so I wanted to ask any organic chemists, if you think he managed to separate the triglycerides with this process?

2 hours ago, John Cuthber said:

no.

You need to look at what catalysts do.

yes... bad slip, i meant "stabilizer" :S

And on that note (forgive my ignorance), what keeps the ammonia in your supermarket bottle from coming apart?