It is easy to find information about heavy-hydrogen water production, but not about heavy-oxygen water. How is heavy-oxygen water commercially produced (for both heavier isotopes)?


1 Answer 1


As far as I know, while fractional distillation would be a suitable technique to obtain O-18 water (yet, in very low yelds and in a way that is hard to control), the most used method nowadays is the membrane distillation technique: basically, a semipermeable and hydrophobic membrane is employed during the distillation (tipically made in PTFE), and the isotopes are separated by their ability to permeate through the membrane: lighter isotopes (O-16 water) tend to flow through the membrane, while heavier isotopes (O-18 water) are trapped in the apparatus and recovered.

You can find many detailed descriptions online, for instance:



  • $\begingroup$ Worth noting that (at the lab scale, not industrial) it seems like fractional distillation has been used to enrich 17O pubs.acs.org/doi/abs/10.1021/ac1022887; if it works for the much rarer 17O, it presumably works for 18O as well? $\endgroup$
    – Curt F.
    Oct 20, 2022 at 17:35

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.