3 ms·

> distillation is only good if the boiling point of a given chemical is higher than that of water What about fractional distillation?

ryanmercer 7y ago
First, I am not a chemist but this is something I've thought aobut a lot as a camper, a "prepper", and someone interested in Mars colonization (perchlorates!). That would work but I imagine it's going to have some amount of inefficiency depending on the contaminant, you'd have to do several passes to get to really low trace levels I imagine as you're going to keep some contamination simply by what collects on the walls of the vessel and runs back down. With some contaminants I imagine you could introduce more chemicals to get a reaction that would make the filtration easier. I imagine some could also be changed sufficiently by heating the sample to a point where you get a chemical change in the contaminant, although, I'm guessing this would be the most 'expensive' method unless energy wasn't an issue (fusion).
- logfromblammo 7y ago
  Take three fractions, the first being the "heads" or "tops" from the first condensed volume up to 5% of the original volume, the next being the "mains" from the next 90%, and the last being the "tails" or "bottoms" from the final 5%. Wash the packed column and boiling vessel with the heads and then discard them. Discard the tails. Repeat the process with the mains. Your twice-distilled mains are now pure water, discounting contamination from inferior distillation apparatus. Get some food-grade calcium chloride (E509, de-icing salt), magnesium sulfate (Epsom salt), sodium bicarbonate (baking soda), and potassium chloride (NoSalt brand table salt substitute) and add some (known) minerals back into the result for your drinking water, because pure distilled water has a very poor taste profile. The only types of chemical that cannot be easily removed by this distillation process are those that form azeotropes with water, such as ethanol, and those chemicals are unlikely to be present in quantities significant enough to be a problem.

ryanmercer 7y ago

First, I am not a chemist but this is something I've thought aobut a lot as a camper, a "prepper", and someone interested in Mars colonization (perchlorates!). That would work but I imagine it's going to have some amount of inefficiency depending on the contaminant, you'd have to do several passes to get to really low trace levels I imagine as you're going to keep some contamination simply by what collects on the walls of the vessel and runs back down. With some contaminants I imagine you could introduce more chemicals to get a reaction that would make the filtration easier. I imagine some could also be changed sufficiently by heating the sample to a point where you get a chemical change in the contaminant, although, I'm guessing this would be the most 'expensive' method unless energy wasn't an issue (fusion).

logfromblammo 7y ago
Take three fractions, the first being the "heads" or "tops" from the first condensed volume up to 5% of the original volume, the next being the "mains" from the next 90%, and the last being the "tails" or "bottoms" from the final 5%. Wash the packed column and boiling vessel with the heads and then discard them. Discard the tails. Repeat the process with the mains. Your twice-distilled mains are now pure water, discounting contamination from inferior distillation apparatus. Get some food-grade calcium chloride (E509, de-icing salt), magnesium sulfate (Epsom salt), sodium bicarbonate (baking soda), and potassium chloride (NoSalt brand table salt substitute) and add some (known) minerals back into the result for your drinking water, because pure distilled water has a very poor taste profile. The only types of chemical that cannot be easily removed by this distillation process are those that form azeotropes with water, such as ethanol, and those chemicals are unlikely to be present in quantities significant enough to be a problem.