If you're wanting to remove the salt out of salt water, Im afraid your only choices are:
Distillation, Or the Process of Reverse Osmosis.
There are portable Desalinators but these are not your average Camping/Preparedness filters. These are portable R.O. pumps and I believe they run about $1000.
There are three basic categories of pathogen that can be found in untreated water:
The first is protozoa. Protozoa include the well-known Giardia, and the not-so-well-known Cryptosporidium, or Crypto for short. These two have been detected in 90% of U.S. surface water and very common in Canada. Protozoa are the largest organisms of the three categories, ranging in size from 1-16 microns. They are more resistant to disinfection by iodine or chlorine than either bacteria or virus, but can be effectively filtered.
Giardia is relatively large and easy to catch, but Crypto is smaller, "more likely to pass through units which depend upon filtration for parasite removal. To know whether or not a filter will protect you against Crypto, find out if it's been tested with Crypto and proven to remove 99.9% of this organism.
The second category is bacteria. Bacteria include such commonly-known organisms as Campylobacter, E. coli, Vibrio cholera, and Salmonella. Bacteria are intermediate-sized organisms, ranging from 0.2 to about 10 microns. They respond well to disinfection, and can be effectively filtered by any filter that is proven to remove 99.9999% of bacteria.
The third category is viruses. Commonly known viruses include Rotavirus, Hepatitis A, Norwalk, and Polio. Viruses are truly tiny; they range in size between 0.02 and 0.085 microns, which makes them extremely difficult to filter. Viruses respond well to disinfection, and can be effectively inactivated using a purifier proven to remove or inactivate 99.99% of virus.
One of the few filters good enough to Qualifiy as a " Purifier " without using any further chemical treatment to disable viruses is The folowing one.
Independent Certification to EPA Microbiological Guide Standard
First Need XL Water Purifier from REI.com