This air filter clean the salt in the air ? the saltpeter ?
I want some solution against saltpeter and corrosion on eletronic equipaments
Well, that's a complicated question.
First answer. The filter will indeed capture airborne salt particles in the main filter, so one valid answer is yes, if the particles are airborne, this will capture them up to the point that the filter, itself an electronic device, becomes compromised by the salt.
The second answer is, maybe. If you have that kind of salt air issues, and aren't living on the bonneville salt flats, chances are you are next to an ocean or sea. This means that MOST of the salt will be condensing on the surfaces and not remaining airborne long enough to filter out. Then the second half of the first answer applies: until the salt ultimately compromises the electronics in the filter.
So, a short term solution is possible, but the long term fix in that kind of really harsh environment is a whole-house, positive pressure system with a water scrubber is really the only thing that will truly desalt your air to the point that it won't destroy the electronics.