I’m confused if it is a marketing term or if it’s a real way to make safe drinking water? If you distill water you are physically removing contaminants, which makes sense that it is safe to drink. De-ionizing is like removing ions, but what does that mean, is the water now cleaner?
In: Chemistry
Water usually contains ionised minerals. Deionising the water removes them. They can be removed. It’s probably not unsafe to drink, but it’s expensive and doesn’t taste good.
So, many things that dissolve into water do it as ions. Mostly minerals, acids, bases, that kind of thing. DI water is water with these impurities removed. Even water that you might normally think of as purified is still fairly mineral heavy compared to DI water.
You know how spirits are distilled and filtered from a mixture of certain things and you end up with alcohol.
Well if you do that with tap water, you get just water… With no minerals or any other deposits in it.
>is the water now cleaner
In a manner of speaking, yes.
Di-ionized water has had the dissolved minerals removed. Irrelevant (or even unhelpful) if you want to drink it, important for the long term preservation of machinery using the water. The minerals can be left behind as residue.
Ions are salt. Sodium, potassium, chloride, magnesium, etc. Ions are also called electrolytes in some food products. Same thing. They are good for you in general, and necessary for life.
These ions can be lowered or removed in two ways. The first is by boiling the water and cooling the steam down to liquid. This is called distillation. It significantly reduces dissolved salts, but a good amount still remain.
The second is reverse osmosis and ion exchange. This uses fancy filters that literally push the ions out of the water. It can result in very high purity to almost chemically pure water. This is called deionized, as it has little to no detectable ion content.
Distilled water is used when some salt is OK but not a lot. Like clothing irons, where you don’t want residue from salt to build up inside.
Deionized water is used in situations where you don’t want any salts at all, mostly in chemistry and medicine manufacturing, or in cleaning electronics.
It is unsafe to drink deionized water. It will literally pull out ions from your cells, damaging your insides. A little bit is OK, but you shouldn’t drink it in large amounts. Like a single cup can harm you. A liter or two can kill you.
Distilled water is safer to drink as it still has ions, but it is not better for you than water with full ions (it’s worse for you). You shouldn’t drink too much, but it won’t rip your cells apart like deionized. It’s really only desirable to drink if you are in a survival situation, like drinking sea water or river water that you distill to lower salt and bad contaminants.
Some home drinking water taps, and bottled water, uses deionized/reverse osmosis water that is then redissolve with salts.
This allows you to remove bad tasting salts like Magnesium, purify sea water in large quantities for drinking, and also remove any heavy metal impurities like lead. Ions like sodium and potassium are always added back to make it safe to drink.
So, always drink water with electrolytes/ions. If you distrust your municipal water supply, you can buy a reverse osmosis and re-ionization kit and install it in your kitchen tap.
DISTILLED water is safe to drink. This is essentially evaporating and condensing the water to remove anything that didn’t evaporate along with the water.
DEIONIZED water is a chemistry thing. It doesn’t necessarily make water unsafe, but it doesn’t make it safe to drink, either.
Normal water is full of ions. Run water through a steel pipe, pick up some Fe+ ions. Run water through the ground, pick up ions like from salt (Na+ and Cl-). These ions are present in minute quantities and give water that “mineral flavor.” Since these ions are charged, you can run the water through an electric filter which grabbs anything charged. This is useful if you want to make sure a few part-per-million chlorine isn’t reacting with a chemistry experiment, but it’s not meaningfully affecting drinking water.
If the water is coming from lead pipes then yes–deionizing will make it safer. But it wouldn’t remove bacteria or pathogens if you’re trying to drink pond water.
People get into a bunch of pseudo-science or alternative medicine/lifestyle nonsense; related to this many people also like to connect “nature” to “pure”.
In nature if you have a river with clean water – the water is going over rocks and naturally some of the minerals in the rock end up in the water. Iron, Calcium, Magnesium, Potassium, and more – and that’s not necessarily bad for you, often it’s a good thing.
Even though it’s good, clean, and safe – it’s not pure. Now if you have a device that say turns this water into steam or mist – lets say a clothes iron, steamer, humidifier, CPAP machine, etc – the water comes out, but the minerals stay. Then you get a mineral build up which you might have to clean, or it might eventually clog the machine.
With distilled water – the water is boiled in a still, and the steam is cooled to have nearly pure water without those minerals. This water is great to use in those devices and is technically pure water. It’s also great for washing a car – as it dries without leaving spots.
Iron, Magnesium, Potassium, and Calcium are also metals. When these are in water, they conduct electricity and that’s why water can damage electronics. When you remove these from the water, distilled water won’t end up conducting electricity so it can be used to clean electronics more safely. So distilled water is also called de-ionized water. Theoretically water can be de-ionized/purified by other methods also.
However some people like the idea of “pure” water, so they might drink deionized / distilled water as it doesn’t contain significant amounts of minerals. Mineral water is the opposite, where the water came from an area where it got lots of minerals in it. These minerals can also act as electrolytes.
In Flint, Michigan they were paying for Detroit water and they had a river with pure, clean water. Someone thought – “Why pay for dirty Detroit water, when we have the Flint river with pure, clean water?”. Well the minerals in the Detroit water coated the inside of the lead pipes and this coating protected people from the lead. When they pumped purer cleaner water, it cleaned the pipes removing the coating and it absorbed the lead. Sadly many of these pipes were in people’s houses which made it a difficult situation.
Today people often try to look at things as being good and bad as a way to over-simplify it. Which water is good, which is bad? Well any water that’s safe to drink is better than sugary drinks.
Distilled water is more “pure”, but it’s definitely not more “natural” which results in a lot of pseudo-science nonsense in favor of one or the other. Another example was the alkaline fad trying to say acids are bad, but Apple Cider Vinegar and Lemons are good.
In my culture, we have a proverb that roughly translates to “moderation is key”. Too much water will kill you, and too little will kill you – but if you have a reasonable/moderate amount you don’t have to worry. A lot of salt is unhealthy, too little salt is also unhealthy – a pinch of salt as an electrolyte won’t do anything bad.
Distilling takes heat. Heat costs money.
If you pass water through a special resin bed, it takes things out of the water. There are resins that take EVERYTHING out.
At scale, it becomes cheaper to deionize water rather than distill it.
Deionised water and demineralised water are interchangeably used to describe water that has had all other contaminants removed. That is to say it is pure H2O molecules with nothing else dissolved or suspended in the solution.
Some other people have mentioned distilled water. This is different to water that has been boiled and then cooled to make it safe to drink.
Distillation involves boiling water into steam, which leaves the impurities behind. The steam is then separated from the impurities before condensing back into a liquid where again it is pure H2O with no other molecules dissolved or suspended within the solution.
Source: Am water treatment engineer.
Deionized water is mainly used for the “spot free rinse” in car washes. Minerals cause the spots, deionization removes the minerals.
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