Removing fluoride (F-) from water is not a challenge for current day technology, and has not been for many years. However, for the consumer of tap water simply “filtering out” F- from water is not a health panacea because anytime technology is applied to water, the water changes and in so doing can present new health risks to that very same consumer. Let’s take a look at how you and I can remove F- from our drinking water and what the caveats of doing so are.
- Reverse Osmosis (RO) – By far RO is the most consumer friendly, potentially safest technology man has for filtering water. RO is not specific for any contaminant, but because of the RO membrane’s small pore size, 98% or more of all mineral contaminants are indiscriminately removed. So yes, RO will remove F-, and also Calcium, Magnesium, and on it goes. The caveat is that chlorine has to be removed before the RO membrane. The removal of chlorine makes it possible for the growth of algae, fungi, bacteria and other microorganisms to grow. If you use RO, post filtration such as ultraviolet lights and 0.2 micron filters are mandatory; as is routing sanitization.
- Anon Exchange Resin (IX) – There are a variety of IX resins that can be used to remove F- . Anion resins remove ions with a negative charge, so they also remove things like chlorides and sulfates. The first caveat is that the word “exchange” is crucial in understanding IX. In order for anion resin to capture a F- ion, it must give off or “exchange” something in its place. Usually,the anion resin will give off a hydroxide ion (OH-) for every other negative ion it exchanges. This generally changes the pH of the water. The additional caveats of IX are that it only has a fixed life/capacity that can only be determined by a chemical analysis of your water. Also, depending on the concentration of F-, which is usually low, the resin will wind up becoming exhausted rapidly with the other more concentrated anions in your water. The expense for removing F- will be very high. Unfortunately, ion exchange resin can’t differentiate between F- and the other anions in your water.
- Mixed-Bed Ion Exchange Resin (MBR) – MBR removes all charged ions, so it will absolutely remove F-. MBR however produces ultra-pure water which is highly corrosive. As such, it will leach metals like copper and lead from your pipes and fixtures. Some home filtration products utilize MBR but the capacity/life is very short and ultra-pure water, while safe to drink, quickly, immediately begins to degrade the very moment your pour it. I do not recommend MBR for home drinking water solutions.
- Zeolites – Zeolites can be man-made or naturally occurring substances. I have included a link on a past article on this topic. More home filtration products are using these less-well-known technologies, and the caveats are too many to mention here.
In my humble opinion, the very best, safest, worry-free way to obtain fluoride free water is to consume high-quality bottled water. Unless you are well versed in chemistry, physics, biology and higher mathematics, managing your own home water-filtration system will present perhaps more dangers and headaches than the F- you are removing.