I am designing an in-situ FTIR experiment in which I plan to adsorb hydrogen peroxide (supplied at 30%, aqueous) onto a zeolite. I would like to avoid co-adsorption with the water. Is there a good method of separating the two components? I was thinking of using something like a mol. sieve or CaSO4 filter between the peroxide reservoir and FTIR cell. An alternative may be to boil the solution under vacuum and simply purge all of the water vapour, but I believe this would be relatively unsafe.
you may think of the N2 purge that can connected to your FTIR machine. Then you can control the water amount in your expriment with a aqueous/humidity meter in line.
Hope it helps, please check if you can have a supply of N2 to your FTIR
Regards
I don't think, that boiling will help to separate them.They have comparable boiling points. One possibility could be synthesis of hydrogen peroxide,perhaps it helps!
best regards.
Instead of using an aqueous solution of hydrogen peroxide, you can try to produce H2O2 in the gaseous phase via heating of solid tablets of H2O2-Urea adduct. These tablets can be purchased from usual chemical suppliers.
I second Olivier's suggestion, look for anhydrous sources of H2O2 like urea-H2O2. Separating water from H2O2 is not straightforward, and it is better to make it in an ahydrous environment. I would be careful about heating until you have done a thorough and careful reading of the literature and reactivity of the molecule, given the propensity of peroxides to react or decompose violently.
I would avoid putting solids or so into your H2O2 solution because in order to avoid decomposition of H2O2 three things have to be fulfilled: 1. No alkaline compounds (H2O2 reacts slightly acidic); 2. No heavy metals (also no traces) and 3. No solid particls (also neutral ones matter). You could concentrate the H2O2 on a hot sand bath and then destille the stuff into fractions. This way it should be possible to get a fraction with almost 100% H2O2. It was described in the literature that H2O2 is in some sense quite thermally stable. If you read German read this article. Good luck and be careful.
R. Wolffenstein, Concentration und Destillation von Wasserstoffsuperoxyde. Berichte der deutschen chemischen Gesellschaft, Volume 27, Issue 3, Seiten, 3307–3312, Oktober–Dezember 1894.
I suggest N2 is purged in hydrogen peroxide first to take gas-phase mixture out. Then, the gas mixture is introduced into water absorbent, which only adsorbs H2O. Finally, gas-phase H2O2 is adsorbed onto zeolite. Hope it works.
I'd prefer the way of producing H2O2 just before it gets in contact with the zeolite. What about sodium perborate or sodium percarbonate? You could use a gas mixture consisting of nitrogen with a very low water concentration and purge it through a fixed bed consisting of one of these substances right before the gas stream gets in contact with your zeolite.
I agree with the previous suggestions that the purge with N2 will be useful.
I have not personally done this, but am aware of several groups that have. For example Smith et al. (2011) in the Astrophysical Journal, 743, 131 state that they used "trap-to-trap distillation and shaking under reduced pressure
(∼10−1 torr) to first 70% and then 99.5% H2O2 by mass" from what was initially a 30% solution. I would imagine you could use a similar approach - maybe try to contact these authors for more details on how they did it...
Thank you everyone for your great suggestions. I think for now I will try the N2 purge idea (using my 30% solution) through an adsorbant, while I am waiting on chemicals, namely urea peroxide.
Again, many thanks for your recommendations.
Check out the solid-liquid phase diagram. The best solution to separate them (used in the industry) is freezing :)
http://www.h2o2.com/technical-library/physical-chemical-properties/physical-properties/default.aspx?pid=23&name=Solid-liquid-Phase-Diagram