Bio-Rad Bio-Rex® Reactor Grade Resins - Manual (Page 5)

Regenerate the cation exchanger using 3 bed volumes
of 3 N HCl and rinse with 4 bed volumes of deionized
water or until the effluent is >pH 5. Regenerate the anion
exchanger with at least 10 bed volumes of 3 N NaOH and
rinse to <pH 9 with deionized water. Regeneration flow
rates should be about 2 ml/min/cm
2 .
Mix the resins thoroughly in the original column by
gently backwashing with deionized water while agitating
with a stirring rod or air, then stopping the upflow and
continuing to stir as the resin settles.
Shelf Life
Mixed bed ion exchange resins are stable for 2 years
when stored at 21 °C and protected from exposure to
ultraviolet light. The shelf life may be extended by storing
the resin at 4 °C.
Applications
AG 501-X8 and Bio-Rex MSZ 501(D) mixed bed
resins may be used to prepare non-ionic reagents for criti-
cal analytical applications. Either the batch or column
method may be used to obtain purified urea, acrylamide,
7 6
occurs at the bottom of the column. If the column is not
used for more than 1 week, it should be washed with 3
bed volumes of water prior to use.
Regeneration
Mixed bed resin used in laboratory-scale applications
is not normally regenerated because the of the difficulty in
separating the mixed anion and cation resins, the large
volumes of regenerants required for the anion resin, and
difficulty in accurately remixing chemically equivalent
resins. The following procedure may be used and is cost-
effective for large-scale applications.
To regenerate a mixed bed resin, separate the anion
exchange resin from the cation exchange resin by back-
washing the resin in a column. First use a low flow rate to
expand the bed. This separates the bed into two regions:
the anion exchanger on top and the denser cation exchang-
er on the bottom. Then slowly increase the flow rate to
carry the anion exchanger out the top of the column and
into a separate container. An alternative separation method
is to shake the resin in twice its volume of water, let it set-
tle, and decant the top layer containing the anion exchang-
er. This procedure is repeated until separation is complete.
LIT205B 6/17/98 12:15 PM Page 6