Sadly, if you have a chemistry degree it was wasted. Buffering is a function of pH, Na and Cl will not affect the pH. Other salts like calcium carbonate can adjust the pH, but there is no buffer. If you wanted a good example of a buffering system in a biological setting, please search for 'blood buffer' or something similar. Humans have multiple blood pH buffering systems or ways of adjusting our blood's pH including how fast or slow we breathe. As for the loss of ions in our blood, in this situation I would worry about sommething else. If someone was looking to drink this water (survival situation), then odds are that the person is eating canned food and getting plenty of sodium. Search for "renin angiotensin". That gets a bit complicated, but at the end of the day, the body has more than one way of getting rid of excess sodium, and most of those physiological systems involve potassium retention. So you would be drinking water low in sodium, eating food high in sodium, and conserving potassium as a result. Sounds good to me. Filter and treat like all other water, and it is a good idea.