Draeger
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Is a sodium sulfide/polysulfide/thiosulfate solution alright for halogen neutralization?
I was wondering if it was safe to use a mixture of sodium sulfide/polysulfide/thiosulfates for the neutralization of halogens? I thought maybe that
would be a cheap neutralizing mixture, considering the cheap price of both S and NaOH.
Collected elements:
Al, Cu, Ga, C (coal), S, Zn, Na
Collected compounds:
Inorganic:
NaOH; NaHCO3; MnCl2; MnCO3; CuSO4; FeSO4; aq. 30-33% HCl; aq. NaClO; aq. 9,5% ammonia; aq. 94-96% H2SO4; aq. 3% H2O2
Organic:
citric acid, sodium acetate, sodium citrate, petroleum, mineral oil
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woelen
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Yes, such solutions can be used for neutralizing halogens. Working with them is smelly though and the reaction product also is dirty (sulfur will
precipitate from the solutions and foul-smelling products may be formed).
If you use a pure thiosulfate solution, without the sulfides, then the process will be much cleaner and have no smell.
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Fluorite
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For halogens it should be okay but can it be used to dispose mercury or lead? I tried adding sodium polysulfide to chromium chloride solution and saw
a black precipitate
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teodor
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Lead in alkaline media could be precipitated for sure, except organolead compounds which needs addition of iodine first (that was discussed in the
thread of lead detection in water). I think that bleach is an alternative to that because it precipitates lead as PbO2 but I am not sure how
completely it does.
Not all the metals (especially complexes) could be precipitated with sulfides, so this rule is not universal but works in many case, you should check
the chemistry of every cation in question.
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Fluorite
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Quote: Originally posted by teodor  | Lead in alkaline media could be precipitated for sure, except organolead compounds which needs addition of iodine first (that was discussed in the
thread of lead detection in water). I think that bleach is an alternative to that because it precipitates lead as PbO2 but I am not sure how
completely it does.
Not all the metals (especially complexes) could be precipitated with sulfides, so this rule is not universal but works in many case, you should check
the chemistry of every cation in question. |
i added calcium polysulfide to copper chloride and a brown precipitate appears immediately but also with lead chloride i saw brown precipitate ? isnt
lead sulfide black?
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Bedlasky
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Cu and Pb sulfides are both black. These metals are precipitated as sulfides from acidic solution, in basic solution there is also formation of some
hydroxide. Btw. polysulfides release sulfur when precipitate metals.
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zed
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Ammonium Polysulfide, worries me. One of my fellow lab employees, broke a large reagent bottle on the floor one time.
Jesus, what an unpleasant stink. As I recall, he might have asked me for suggestions on how to deal with it.
Being unfamiliar with the material, my first impulse, would have been to neutralize it with acid, to put a stop to the overpowering ammoniacal stench.
This clever move of course, might have killed everyone in the building.
Ammonium PolySulfide, when treated with strong acids, can release free Hydrogen Sulfide Gas.
Drop you in your tracks. Something to consider, if it hasn't previously occured to you.
[Edited on 24-12-2020 by zed]
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RustyShackleford
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Unless you have a large amount of halogen to neutralize i would opt for something different, polysulfides and sulfur in general are horrible to work
with. thiosulfate isnt expensive and neither is sulfite
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