No registration or passwords; no pop-up ads -- just aloha, fun, & answers.
(as an eBay Partner & Amazon Affiliate earns from qualifying purchases).
Home /
T.O.C.
Fun
FAQs
Good
Books
Ref.
Libr.
Advertise
 
Help
Wanted
Current
Q&A's
Site 🔍
Search
pub  Where the
world gathers for metal finishing
Q&As since 1989



-----

Why is degassor after Strong Acid Cation and before Strong Base anion?




March 25, 2011

Dear sir
Why degassor is always after Strong Acid Cation and before Strong Base anion?

I also want to know, can we check Degassor performance?
What is the method of check Degassor performance?

Regards
Mahendra singh Chouhan

Mahendra Singh Chouhan
Chemist - Nimbahera Rajasthan India



The answer to your question can be found in the CO2/HCO3-/CO3= equilibrium as a function of pH. If you google this, you should be able to get a very informative graph of this equilibrium.

At a neutral pH, most of the carbon dioxide is present as bicarbonate ion, HCO3-. Passing through a cation exchange resin in the hydrogen form reduces the pH, usually to between 2 and 3. This drop in pH converts virtually all of the HCO3- ion to dissolved, non-ionic CO2 which is then free to outgas and leave the water.

So, degassing after the cation exchange resin can remove most of the bicarbonate ion that was present in the feed water. This can significantly reduce the ionic loading on the anion resin and reduce the amount of sodium hydroxide [affil links] needed to make de-ionized water.

There are may ways to tell if your degassifier is working. One is to measure the total inorganic carbon in the water before the cation exchanger and after degassing. Another is by the pH. The pH as previously mentioned will fall to between 2 and 3 when it leaves the cation exchanger. After a properly operating degassifier, the pH will rise significantly, probably to a value between 4.5 and 6. The precise pH values will vary with the initial water pH and bicarbonate concentration, and how well your degassifier works, but, assuming that your feed water does not change, the values should be very close to the same, day after day.

Lyle Kirman
consultant - Cleveland Heights, Ohio
March 28, 2011




(No "dead threads" here! If this page isn't currently on the Hotline your Q, A, or Comment will restore it)

Q, A, or Comment on THIS thread -or- Start a NEW Thread

Disclaimer: It's not possible to fully diagnose a finishing problem or the hazards of an operation via these pages. All information presented is for general reference and does not represent a professional opinion nor the policy of an author's employer. The internet is largely anonymous & unvetted; some names may be fictitious and some recommendations might be harmful.

If you are seeking a product or service related to metal finishing, please check these Directories:

 
Jobshops
Capital
Equipment
Chemicals &
Consumables
Consult'g, Train'g
& Software


About/Contact  -  Privacy Policy  -  ©1995-2024 finishing.com, Pine Beach, New Jersey, USA  -  about "affil links"