Aldrich

Dowex® Resins - Technical Information Bulletin

 Number AL-142 Ion-Exchange Resins and Related Polymeric Adsorbents

 Dowex Resins

A. Properties
B. Regeneration of Dowex Resins

® Registered trademark of Dow Chemical Co.

A. Properties

We refer the user to the vast amount of general information made available by the Dow Chemical Company through the published literature. The figures and table below should guide in choices of resin, application, and quantities to use.

 

Catalog Number Code Crosslinkage(%) Part. Size
(dry mesh)
Dowex-1-chloride, strongly basic anion
Active group — trimethylbenzylammonium
217379 1X2100 2 50-100
217387 1X2200 2 100-200
217395 1X2400 2 200-400
217409 1X850 8 20-50
217417 1X8100 8 50-100
217425 1X8200 8 100-200
217433 1X8400 8 200-400
Dowex-50-hydrogen, strongly acidic cation
  Active group — nuclear sulfonic acid
217441 50X2100 2 50-100
217468 50X2200 2 100-200
217476 50X2400 2 200-400
217484 50X4400 4 200-400
217492 50X8100 8 50-100
217506 50X8200 8 100-200
217514 50X8400 8 200-400

 

AL-142 image 1 AL-142 image 2
AL-142 image 3 AL-142 image 4
AL-142 Image 5

 

B. Regeneration of Dowex Resins

Normal ion-exchange operation does not utilize the total capacity of the resin for exchange because complete regeneration is impractical. Complete conversion of one ionic form to another may require excessive time and material. If complete regeneration to a given ionic form is desired, the regenerant solution should be passed through the resin at a flow rate equivalent to 1 gpm/sq. ft. of crosssectional bed, until none of the original ion is detectable in the effluent.

The degree of crosslinkage controls the porosity of the resin, e.g., X8 (8%) indicates medium porosity, X2 or X4, high porosity and X12, low porosity. All other factors being equal, more porous resins have higher regeneration efficiency, but lower total capacity.

Highly porous resins have many useful specialized applications, such as large organic ion exchange (M.W. 300400); X8 or X12 suffices for common inorganic ions. Resins of lower porosities have higher capacities (on a volume basis) and a longer useful life under oxidizing conditions.