Fyndium
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Desiccator vs ambient with fan?
Which one is more efficient way to dry moist, wet but not liquid material, outdoors at ambient temperature with fan, or with non-vacuum desiccator?
I've been drying damp crystal mass outdoors recently, but though if I'd move them in desiccator bag with CaCl2 instead.
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EthidiumBromide
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I'd say it depends on how hygroscopic the solid you want to dry is and your relative humidity outside. If it's not very humid and the compound isn't
particularly hygroscopic, a fan will do (though you should occasionally stir the solid to expose more of the wet crystal mass). But if it's a solid
that really likes to draw moisture from the air, then a desiccator is the way to go.
Air drying depends purely on how much water can still get dissolved into the surrounding air at a given temperature and pressure. At high relative
humidity (i.e. the water content being close to saturation at given T and p), it obviously won't be a lot and drying will be very slow (and the
hygroscopy of a substance becomes another factor, the more hygroscopic the less water can effectively get pulled from the substance). Desiccators
generally do a better job of pulling away water, as it is continuously absorbed by the desiccant, so more water can be picked up from the material by
the air inside the desiccator.
[Edited on 13-10-2020 by EthidiumBromide]
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Fyndium
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I actually thought of placing a small fan inside a desiccator bag.
It's getting cold and rainy outside, so the evaporation rates go down.
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EthidiumBromide
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That should speed things up definitely. Dry air + blowing will do the trick.
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Belowzero
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I sometimes use an aquarium air pump (~ 5 watts) to dry substances.
The tube is inserted into the beaker with the material and a watch glass is placed on top.
The pump comes with an inlet filter.
My main issue with air drying is the potential dust blowing into the substances, carefully purifying the material just to contaminate it with dust
seems stupid.
It's slow but more effective depending on the amount on solvent , a dessicator becomes inefficient when the substances contains more than a few ml's
of liquid.
On my to-do list is building a drying box as often used in pyrotechnics, basically a box with an old fashioned light bulb and a tray for holding the
substance.
If done right the chamber has a constant temp anywhere from 30-50 degrees C, this can speed up drying by quite a lot.
[Edited on 13-10-2020 by Belowzero]
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itsallgoodjames
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Dessicator will do a better job in a shorter amount of time, at least for water. Outside with a fan is fine for most things. At least for me, it
depends what I'm doing. If it's something that needs to be fully dry of water, I'd use the dessicator. But if it's an organic solvent like methanol
or acetone, outside with a fan should be more than sufficient
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teodor
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Hm. It is always interesting to discover how people do things especially when a lot of people do it different way than I do.
Most substances I dry on a filter paper with a folded paper towel below the filter paper. To protect from dust I put it in a closed cabinet. Usually
they are dry next day if they are not hygroscopic.
If I need the substance urgently I usually don't wait so long and use it as a solution (most cases) or as wet crystals (for insoluble ones), but in
most cases I really can switch for doing something else until they are dry.
[Edited on 14-10-2020 by teodor]
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Fyndium
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I have recently dried crystals placed directly on top of a fine SS mesh, and below them I've placed a fan to blow air upwards. Last batch of ethanol
rinsed KNO3 crystals appeared completely dry after 15 minutes.
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