[DTU student #12]

Hello, I am a 2. term student of chemical engineering from Denmark

I am currently writing a project about monitoring ammonia emissions from agriculture.
To make a long story short, the project group have chosen first chemisorbing ammonia gas on activated carbon impregnated with sulfuric acid. The theory is that the ammonia will react with the sulfuric acid and form ammonium sulfate.
My question regards how to quantifi the ammount af chemisorbed ammonia (ammonium).

Currently I am thinking that perhaps rinsing the activated carbon with water will remove the impregnated chemical, and make the ammonium ions dissolve in the water. I dont think the ions will adsorb onto the activated carbon, because the molecules are small and polar. I worry, however, that either this wont work at all, or some of the ammonium might escape.

I was just wondering if perhaps there is a better way to do this? I do not yet know about the vast range of different analysis methods, so any hint or alike will be greatly appreciated.

Best Regards

[Borek]

I don't get the idea. If you are using sulfuric acid, why not force the gas through the scrubber?

[DTU student #12]

The idea is to contain the sulfuric acid within the activated carbon for easier handling, as a "dry acid". Then force the ammonia containing gas through the activated carbon, which, I suppose, will be acting sort of like a scrubber?

The problem is quantification of the ammonium that has bonded with the sulfuric acid inside the activated carbon.

Best Regards

[Borek]

I would expect just washing will dissolve both the acid and the ammonium sulfate. Question is - how much will be left on the carbon, and how reproducible is the procedure. But that's what you have to check.

[DTU student #12]

Thats exactly what I was wondering of anyone had any ideas of how to actually analyse the contents of the activated carbon. Perhaps some type of analytical method

I am not sure of this, but I think I've read somewhere that ammonium ions, NH4+, for some reason, does not evaporate like ammonia, can anyone confirm or deny this?

Best Regards

[Borek]

In general ions (and ionic substances) are not volatile.

[DTU student #12]

In case I had some activated carbon pretreated with sulfuric acid, that I had exposed to a flow of ammonia gas. The ammonia, or at least some of it, would become trapped in the activated carbon, due its reaction sulfuric acid, creating ammonium sulfate.

If I were to rinse the activated carbon with an acid solution, would the water content rinse out the impregnation? Ideally a pH level of 7 or less, would ensure that the ammonium ions will not be deprotonated.

Overall, would it be possible to completely (or close to) remove the impregnation chemicals by water rinsing?

Best Regards