Sciencemadness Discussion Board

Turning Oxides into sulfates

aab18011 - 10-6-2020 at 19:19

Ive been so deep in Orgo because of school that I am feeling unsure of where to go in answering this question. I was wondering if I can turn Magnesium Oxide, Silica, and Aluminum Oxide to respective sulfates (or anything else that will allow them to be biologically active).
If you are wondering why I want it to be bio-active: its because I want to be able to take inert material that cannot be used and turn it into something that can be broken down and absorbed by plants/etc. Sulfates of Mangesium are soluble in plants and are used as a natural source of Mg for their Chlorophylls.

woelen - 10-6-2020 at 22:35

Magnesium oxide can be dissolved in dilute sulfuric acid to make magnesium sulfate.
Aluminium oxide can be treated similarly, but when the oxide has been heated strongly, then it has become very inert and then you will have a hard time dissolving it in the acid. In that case, it only dissolves very slowly (days, weeks). Heating it in concentrated hot acid speeds up the process of dfissolving, but still it is slow.

Is silica (silicate, based on that), also biologically active? I have severe doubts about that.
You can get silica in solution, albeit slowly, by heating it with a hot strongly alkaline solution. Then you get a soluble silicate, but I doubt that any living organism used silicon in its metabolism.

Ubya - 11-6-2020 at 01:58

Quote: Originally posted by woelen  
Magnesium oxide can be dissolved in dilute sulfuric acid to make magnesium sulfate.
Aluminium oxide can be treated similarly, but when the oxide has been heated strongly, then it has become very inert and then you will have a hard time dissolving it in the acid. In that case, it only dissolves very slowly (days, weeks). Heating it in concentrated hot acid speeds up the process of dfissolving, but still it is slow.

Is silica (silicate, based on that), also biologically active? I have severe doubts about that.
You can get silica in solution, albeit slowly, by heating it with a hot strongly alkaline solution. Then you get a soluble silicate, but I doubt that any living organism used silicon in its metabolism.


Diatoms build a silica shell around themselves, Diatomaceous earth rings a bell?:D

biosyntheses are weird

Tsjerk - 11-6-2020 at 06:37

Silicon is an essential element in animals and a very important element for many plants species!

Silicon in plants:
Silicon dioxide Wiki, see "natural occurence"

Essential element in animals:
Attachment: carlisle2007.pdf (1.4MB)
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[Edited on 11-6-2020 by Tsjerk]

aab18011 - 11-6-2020 at 11:55

Quote: Originally posted by woelen  
Magnesium oxide can be dissolved in dilute sulfuric acid to make magnesium sulfate.
Aluminium oxide can be treated similarly, but when the oxide has been heated strongly, then it has become very inert and then you will have a hard time dissolving it in the acid. In that case, it only dissolves very slowly (days, weeks). Heating it in concentrated hot acid speeds up the process of dfissolving, but still it is slow.

Is silica (silicate, based on that), also biologically active? I have severe doubts about that.
You can get silica in solution, albeit slowly, by heating it with a hot strongly alkaline solution. Then you get a soluble silicate, but I doubt that any living organism used silicon in its metabolism.


Thanks for the advice Woelen, but like the others said, SiO2 is actually quite necessary for many plants. I am trying to come up with a serious method for taking lunar material/dirt and turning it into plant processable material.

I have built a plaque so I can plan out the synthesis for each compound. I am preparing a research proposal for my laboratory, as we are getting ready to start our undergrad projects. Im hoping to turn this into a way to have plants successfully grow on the moon...

[Edited on 6-11-2020 by aab18011]

volta - 11-6-2020 at 12:23

Al and Si are being taken by the plants too although in small quantity, much smaller than Mg, probably because it is not needed that much, not considered essential nutrient. According to wikipedia:

Silicon is not considered an essential element for plant growth and development. It is always found in abundance in the environment and hence if needed it is available.

Aluminum is one of the few elements capable of making soil more acidic. This is achieved by aluminum taking hydroxide ions out of water, leaving hydrogen ions behind. As a result, the soil is more acidic, which makes it unlivable for many plants. Another consequence of aluminum in soils is aluminum toxicity, which inhibits root growth.

Also you can't make Al sulfate and Si sulfate just by mixing oxide with sulfuric acid, because they will decompose in water to form oxides and sulfuric acid. Al and Si oxides are already abundant in soil and are just enough soluble as they should be to be absorbed by plants. The only way to make them more soluble is dissolving in base like NaOH. But even that will not be stable enogh in natural environment but will react with CO2 which will decrease solubility by reacting and changing pH.

There are of course some edible plants that prefer slightly basic soil, but most will prefer neutral or slightly acidic soil.

[Edited on 11-6-2020 by volta]

woelen - 11-6-2020 at 12:47

Al-sulfate does hydrolyse a little in water, but it certainly can exist as a solution in water and will not completely decompose, unless it is extremely dilute. Freshly prepared Al-oxide certainly gives Al-sulfate with sulfuric acid, especially if the acid is present in excess amount.

Al-sulfate (or alum, which is K/Al sulfate) gives slightly acidic solutions. Such aolutions may be too acidic for certain plants, but other plants thrive on it very well. For some plants, it is added on purpose to the soil for e.g. hydrangeas in order to get beautiful deep blue flowers.

Si-sulfate does not exist. Silicon is an acid-forming element and cannot exist as cationic species in water. SiO2 can be dissolved, but only in alkaline solutions, to give metasilicate ion, SiO3(2-). The latter is quite stable in aqueous solution. One can buy Na2SiO3, which dissolves in water very well and gives clear and colorless solutions. Such solutions precipitate solid, nearly invisible gels of hydrous SiO2 on acidification. At very low concentrations, Na2SiO3 still can remain in solution, and apparently, according to other posts in this thread, there are organisms, which can use the silicate.

[Edited on 11-6-20 by woelen]

aab18011 - 11-6-2020 at 16:17

My thought is that I can use the new Au catalyst to take CO2 and CH4 and turn it into oils and oxygen. This can be used to start producing carbon that can be taken on by minerals. Mixing and finding the right ratios could enable primitive organic soils. Since there is remnants of volcanic activity on the moon, one can make use of pyroclastic ash and other mineral deposits. These will help source natural sources of minerals of various kinds. The truth is, our team has no belief in making the whole moon into some atmosphere-wrapped mini-planet. Rather we are talking about making small sized domes that can have their own controlled atmosphere and use local sources of mineral to produce soil.

So far we have thought of ways of making soil with worms and feeding them this material. Also Tenebrio Molitor and Zophobas Morio larvae are really good at digesting minerals, and can even digest Polyethylene, Polystyrene and Polyethylene Terephthalate. But ensuring that these organisms can live in a lower gravity is of concern...

All of these suggestions give rise to some possible slow processing of soils, as in slowly producing soluble minerals and mixing them in with organic material decomposed. Would probably give better yield.

Sulaiman - 11-6-2020 at 18:05

I guess that chemistry is not the answer, biology would be more likely to succeed,
find combinations of organisms that can terraform lunar soil,
because a few vials of organisms will be a lot easier to transport to the moon than tons of chemicals.

P. S. watch the Matt Damon movie 'The Martian'

[Edited on 12-6-2020 by Sulaiman]

aab18011 - 11-6-2020 at 18:28

Quote: Originally posted by Sulaiman  
I guess that chemistry is not the answer, biology would be more likely to succeed,
find combinations of organisms that can terraform lunar soil,
because a few vials of organisms will be a lot easier to transport to the moon than tons of chemicals.

P. S. watch the Matt Damon movie 'The Martian'

[Edited on 12-6-2020 by Sulaiman]


Maybe I did not make it clear, but I was talking about using lunar soils and minerals to make organic dirt (combined with the gaseous methane and CO2 which can be used to form oils and oxygen). But I am currently looking into a list of organisms that our lab has already done research on. But the chemistry is still important because this will be done small scale for a time.