Can iodine purify any kind of water enough to consume it?

Answer 1

There are a number of chemical methods for water purification.

• Iodine
• Chlorine Tablets
• Laundry Bleach (probably the cheapest)

They will probably all be reasonably effective in killing bacteria, protozoa, and viruses, but may be dosage, time, and temperature dependent. There are a few types of bacteria that it will be ineffective against, including a bacteria in Nepal called cyclospora and as well as a protozoa family Cryptosporidium oocysts. Perhaps other cyst and spore forming parasites could also be problematic.

Note, you can not just mix and drink, and solutions may require waiting a half an hour or more before using.

Here are a couple of good articles on Iodine and Chlorine treatments of water.
http://wwwnc.cdc.gov/travel/yellowbook/2010/chapter-2/water-disinfection.aspx
http://www.high-altitude-medicine.com/water.html

Other than flavor issues, and small does of Chlorine or Iodine (which may be an allergen to some people),
The primary limitation of chemical treatment of water is that it will do absolutely nothing to get rid of chemicals that may be present in the water.

I.E. It will not help if you have petroleum, Methanol, Cyanide, Heavy Metal Contamination, and etc in the water. Activated Carbon filters will help with most of these.