Have recently purchased a monobed deionizer refillable cartridge
for making Class 1 water from a ca 50PPM Reverse Osmosis feed.
I want to regenerate this resin but can't seem to find a generic procedure to do so. This is so called Nuclear Grade resin and a refill
is about $50 for the stuff which changes color when exhausted.
Ion exchange DI resins are regenned by H+ and OH- respectively, no?
Timsolo - 8-10-2006 at 12:35
There is a section on regeneration of this type of ion exchange resins in this article................12AX7 yes, they seem to use
NaOH for the job....solo
Small Column Ion Exchange Testing of SuperLig® 644 for Removal of 137Cs from Hanford Waste Tank 241-AP-101 Diluted Feed
I think you have a mixture of H+ and OH- resin. The H+ can be regenerated with HCl, and the OH- with NaOH. I don't think what you have can be
regenerated without seperating the two types.solo - 8-10-2006 at 16:24
Reference Information
Regeneration of Ion-Exchange Resin in Nonaqueous Media Tsoung Y. Yan* and Paul Shu Industrial & engineering chemistry research yr:1987 vol:26 iss:4 pg:753 [/orange]
Abstract
By use of pyridine in xylene as a model system, it is shown that a cationic exchange resin can effectively remove nitrogen compounds from
hydrocarbon oils. The pyridine laden resin can then be regenerated directly with anhydrous HC1 dissolved in the oil without switching to an aqueous
system. This method is based on the fact that anhydrous HC1 when dissolved in the oil dissociates slightly to yield protons which then exchange with
resin-bound pyridine ions to form an insoluble salt. The insoluble salt is then flushed out of the system. Cationic resins because of their high
loading capacity can be used more advantageously than clays to remove nitrogen compounds from lube oils and distillates and thus improve their
thermal and storage stability. The simple resin regeneration technique described here lends itself to technically and economically viable commercial
processes for the treatment of petroleum products.
Thankyou so much Solo for the very useful information.
.........I think you have a mixture of H+ and OH- resin............
Yes, monobed as I understand it
........The H+ can be regenerated with HCl, and the OH- with NaOH. I don't think what
you have can be regenerated without seperating the two types..........
This was my thought exactly. The dual bed
is probably what should have been purchased and oh well "Live and Learn"
I wonder also what the color change substance is?
This water I'm using for an ionic silver product I produce. Till now have been purchasing RA 2x distilled which costs me about $26 for 20liter
(22liter jug) but sometimes the TDS is a little over 1PPM or so says my home made TDS meter which has proven very accurate against the standards,
Thank god for the 3&1/2 digit Fluke 87 reading my simple dual LM317, AC 9V voltage divider meter.
[Edited on 9-10-2006 by bio2]bio2 - 8-10-2006 at 20:58
Well. 12AX7; Not having ever regenerated
ion exchange resins before in the lab I was thinking more of contact times, concentrations of reagents & etc.
Having built more than a few deminera;izer plants incidental to boiler feed water I am more familiar with the 25HP transfer pumps and acid tanks.
Shit, once a head mounted check valve sprang a leak (3rd day after start up) and by coffee the next morning the acid had eaten 3 feet thru the
concrete and was beginning to dissolve the gratings.
Damn sulfuric tank was 12,000 gallons so that leak would have lasted a few more days, LOL.matei - 9-10-2006 at 05:03
The mixture of cationite and anionite can be separated quite easy because their beads have different densities. Industrially the separation is
achieved by backflushing the ion-exchange column with water. After this, the resin separates in two layers and the cationite and anionite can be
regenerated with HCl and NaOH. After the regeneration they are mixed back with compressed air.bio2 - 14-10-2006 at 01:59
Just what I was looking for. Will try this soon.
Thank you very much.Eclectic - 14-10-2006 at 06:14
Just one bead of the wrong resin while regenerating will trash the whole bed. It will saturate while the bulk of the beads regenerate.Magpie - 14-10-2006 at 15:19
At one of my previous places of employment we had mixed bed ion exchange columns for "polishing" reverse osmosis effluent. They were regenerated as
matei has indicated using 4% NaOH and 4% H2SO4. Eclectic I can't imagine any industrial process for water treatment being so sensitive that just one
bead (or even a 100) out of place would be noticeable.Eclectic - 14-10-2006 at 17:23
That one bead of OH- resin regenerated as H+ will be completely saturated with Cl- (or SO4--). If it ends up at the input of the bed, no problem, but
if it ends up near the exit, it's going to be releasing Cl- (or SO4--) into your high purity water. Saturated H+ resin out of place will be releasing
Na+. My understanding is that there is an ion exchange equilibrium, not absolute binding.
The specific gravity seperation puts the resins into seperate tanks for regenerating? Then they are remixed into a monobed? Were the resins
specifically designed for this procedure? In that case I'd expect better results than I would for a mixed bed that was not designed to be
regenerated.
[Edited on 15-10-2006 by Eclectic]Magpie - 14-10-2006 at 18:46
The equipment and resins were selected to function as a regenerable mixed bed. This part of the plant was not my responsibility so I only gave it
casual attention. I will contact plant personnel and find out the details, i.e., resin type & composition, and regeneration procedure.
[Edited on 15-10-2006 by Magpie]bio2 - 14-10-2006 at 22:53
That would be helpul. I found some info on using 1.5-2.0 equivalents acid or base for regen in a sketchy non-procedure.
It's Amberlite IRN-150 made by Rohm & Hass..
About a 1 Kg jar full with no labeled weight is purported to remove 700grains hardness. Cutoff is 18megohm and the regular stuff is 15mohm
I quess most labs exhange the spent resins to specialty companies. Beats 20L water bidistilled for $26 RA/ACS grade.
A $48 kilo of resin will do almost 500gallons at 100PPM feed water.Eclectic - 15-10-2006 at 07:07
Google: mixed-bed regeneration
All kinds of good info. I couldn't find anything on regenerating IRN-150 though. For a different resin system, there was a procedure for a specific
gravity separation using 50% NaOH
(Ok, so maybe a few beads out of place is not a compleat disaster. Still, it's to be avoided if possible for high purity water)
[Edited on 15-10-2006 by Eclectic]
Domestic water softeners
blazter - 16-10-2006 at 06:23
I could be wrong, but it appears that the industrial device/resin is very similar to a domestic water softener. These typically consist of an approx
4' tall by 1.5' dia cylinder packed with a bed of ion exchange resin of some sort. It then absorbs the Ca ions and other causes of water hardness for
about a week or so depending on how heavily it used. Then for the regeneration, saturated salt solution (brine, NaCl or KCl) is backflushed which
purges the other metal ions from the resin. I dont know the exact reactions/diffusion equations offhand, but this is the general method used to
soften (demineralize) household supplies of water.bio2 - 16-10-2006 at 08:13
You are wrong!
Softeners exchange "hard" minerals for "soft" (Na) and the water is then full of sodium.
Deionizers for Class 1 or 2 water remove all mineral ions nearly completely having a fixed known capacity.matei - 16-10-2006 at 09:17
Quote:
Originally posted by Eclectic
Just one bead of the wrong resin while regenerating will trash the whole bed. It will saturate while the bulk of the beads regenerate.
That's absurd. If, for example, you have one bead of cationite in Na+ form in deionized water (which is H+ and OH- at pH 7) it won't exchange Na+ for
the H+ in the water, because this takes place only at low pH (you use acid to regenerate the resin). Hope I was explicit.Eclectic - 16-10-2006 at 09:45
You were explicitly wrong. I already said I might have been a bit hyperbolic. There is a paper on the Dow resins site that discusses the effect of
incomplete separation and it's undesirability. Ion exchange is an equilibium partitioning between ions in solution and ions bound to resin.unionised - 16-10-2006 at 09:51
The H+ concn might be pretty low, but the Na+ concentration is even lower so the Na+ will leach out.
OTOH, unless the Na saturated bead is just at the output of the column, most of the Na will be stripped out by other beads in the mixed resin bed. If
it is right at the outlet then it will quickly get washed clean.Magpie - 16-10-2006 at 10:20
I promised particulars on an industrial application of a mixed bed column for polishing reverse osmosis effluent, so here it is:
Regeneration: The resins are separted with an upflow of water. The anionic is regenerated with flow of chemical from the top down. The cationic is
regenerated with flow of chemical from the bottom up. Following regeneration the beads are remixed using air/water flow adequate to provide
sufficient agitation.
"The bead separation is not perfect at the interface, but this does not cause any significant problems."Eclectic - 16-10-2006 at 10:43
Unionised: yes, that's what I realized after doing some googleing.
Magpie: thanks for the details.
I had not been aware of regenerable mixed bed systems.
Talking out my hat. My bad....
Still, back to the original application, it appears that the IRN-150 system was not designed to be regenerated, and at $50 per 500 gallons treated
water, might not be worth the trouble to regenerate if it was. If there is a clear visible difference between the two resin types, you could try a
specific gravity flotation separation starting with 50% NaOH and diluting untill one type clearly sinks while the other remains floating. Some resin
systems have a color difference between the two types that would make it obvious.
[Edited on 16-10-2006 by Eclectic]bio2 - 16-10-2006 at 17:34
......it appears that the IRN-150 system was not designed to be regenerated...........
I did not see this information on the Rohm & Hass website after spending a while there. This "Nuclear" grade resin simply means it has the
lowest possible level of contaminents.
The resin beads are different color one being more clear than amber. I will try your separation suggestions in a test tube to see what happens.
This has turned into a good thread and thanks to everyone.
After the "trip" to Rohm & Hass it makes one realize that there
is a lot to know about ion exchange resins. Really a specialty
field in itself.ScienceGeek - 30-4-2008 at 15:45
Bringing up an old thread here...
bio2, how did it go? Anyone else with any results?
I was recently given an old "Crystalab d-ionizer", and I would much like to regenerate the beads! Now I know how to do it, but I find the description
on how to separate them a little vague. Anyone have any good procedure for someone to do this at home?
