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topic 34307

Deionized vs. distilled water



A discussion started in 2005 & continuing through 2017

(2005)

Q. I work in a soil lab and need to understand the difference between deionized water and distilled water. What is the difference? Can they be used interchangeably?

Mary Innes
University of California - Sonora, California, USA


(2005)

A. Though both methods will produce fairly pure H2O, I believe their difference may primarily be found in their processes. Distilled water is made by boiling impure water (most solutes get left behind), then collecting the condensation in a separate container. This process may be repeated many times before considered complete. Deionized water is usually produced by running it through a series of filters. These include but are not limited to charcoal filters and semi-permeable ion membranes. I believe deionized water can be more pure if you have some high-dollar equipment.

Jon Hooker
- Hutchinson, Kansas, USA


First of two simultaneous responses -- (2005)

A. Jon's post is good, but not technically correct. Filtering water thru extremely fine filters is called ultra filtration. Filtering it thru activated carbon removes much of the chlorine and some of the organics. Water can be forced thru a membrane under pressure to get a reasonable quality of water is called RO or reverse osmosis. DI water is a water produced by an ion exchange process in a chamber (s). It removes most of the anions and cations leaving pure to extremely pure water. It must be periodically regenerated.

James Watts
- Navarre, Florida


Second of two simultaneous responses -- (2005)

A. It's all horses for courses. The main difference between DI water and distilled is that in DI water, as the name suggests, it has had its unwanted ions taken out and replaced with hydroxide and hydrogen as applicable. Distilled water has been boiled and condensed. This not only removes all the rogue ions but it also removes many of the dissolved gases, which DI water doesn't do. Saying that, leaving distilled water for any time will allow gases to redissolve and you will be back to square one. If you are doing serious analytical work, I would recommend you use distilled water, and preferably triply distilled water (i.e. distilled three times). It must also be very fresh. If you are doing routine chemistry where absolute purity is not important, use the cheaper DI water.

trevor crichton
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK


(2006) -- this entry appended to this thread by editor in lieu of spawning a duplicative thread

Q. I am a year 11 student and have a question in my assignment that I am struggling with. The question states "Distinguish between distilled and deionised water"I would greatly appreciate someones help.

Ellen L
- Bullsbrook, western Australia, Australia


July 18, 2008

Q. DOES THE pH VALUE OF THE DI WATER CHANGE AFTER IT IS PASSED THROUGH THE RESIN COLUMN? IN THE SCHOOL LAB WHERE I WORK WE USE THE SIMPLE RESIN AND PASS THE WATER THROUGH IT. IT WAS NOT GIVING ANY PRECIPITATE WITH SILVER NITRATE IS WAS NOT CAUSING ANY PROBLEM.RECENTLY WE ACQUIRED A pH METER AND WE ARE FACING PROBLEMS.CAN YOU SUGGEST AWAY OUT
RAVI

RAVI KOMARAGIRI
- madannapalle Andhra pradesh India


March 8, 2012

Q. We have been having problems with deionised water and our Daphnia Magna; we think it has killed them. Can we have some help. Thanks.

Alexandra Gugenheimen
- Berlin, Germany


April 9, 2012

We have been having problems with deionised water and our Daphnia Magna; we think it has killed them. Can we have some help. Thanks.

A. What else are you giving them? Organisms need trace amounts of minerals and ions to survive (an experiment showed mice prefer to drink water with trace amounts of metal rather than pure water), so if you're just giving them deionized H2O and food, yeah, poor things may be lacking!

I use spring water for my Daphnia and they get along pretty well. Alternately you can use tap water, but be sure you let it sit for at least a day to allow chlorine gas (which would kill the daphnia) to escape. I usually just fill up a carboy on Friday and then use it monday.

Kyle Gray
- Waterford, Michigan, USA


August 9, 2012

How would distilled water be produced for routine work in the laboratory?

Ugwu jenny
- UDI.ENUGU STATE NIGERIA


Beginner's Distillation Kit

August 10, 2012

Hi Jenny.

You can get a kit for learning how it's done =>
or a packaged distillation unit of almost any size. Good luck.

Regards,

Ted Mooney, finishing.com Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey


February 26, 2013

Q. How would you produce distilled water for routine use in the laboratory?

Abraham james ijanasu
- Adamawa state of nigeria


February 26, 2013

A. Hi Abraham. I'm trying, unsuccessfully so far, to understand how your question differs from Jenny's, which I just finished answering. If you don't understand something, please try your best to frame your question in terms of the answers already offered instead of just posting the very same question again with no clue about why you don't understand the answer. Thanks.

Regards,

Ted Mooney, finishing.com
Teds signature
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey



March 27, 2013

Q. Hi everyone,

We test WFI quality water and, as part of the test for Nitrates, it states to place the samples and standard in a waterbath @ 50 °C for 15 minutes. I have been looking into what tolerance the Pharmacopoeias would place on the water bath but can't for the life of me find anything.

Anyone out there have any idea?

Thanks

Mark

Mark Rowe
- Cramlington, Northumberland, UK



December 8, 2017

Q. I am currently conducting some home-based experiment, and the process requires me to use de-ionized water. Alas, I have only so much available to me in resources. I have read of the many similarities between distilled and de-ionized water. Is there an effective, inexpensive method for de-ionizing water at home? Any help would be greatly appreciated.

Justin Carter
- Atlanta, Georgia, USA


December 2017

A. Hi Justin. You can buy distilled or de-ionized water inexpensively by the gallon from supermarkets. It's used for a lot of things like in steam irons.

There isn't a cheap and easy way to make it at home, although you can "Call your Culligan man" or his competitors and rent a de-ionizing system if you need more than a few gallons, or buy a de-ionizer. Good luck.

Regards,

pic of Ted Mooney
Ted Mooney, P.E. RET
finishing.com
Pine Beach, New Jersey
Striving to live "Aloha"



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