Potable Water: Because Iodide (I-) has such a high selectivity for a Type I strong base anion exchange resin like DOWEX™ 1 (see table of selectivity data (82KB PDF)) it is essentially a selective removal. The high selectivity of DOWEX 1 also means that regeneration can be difficult.
DOWEX 1 meets NSF / ANSI Standard 61 for contact with drinking water. For more information see our regulatory information.
Selective iodine removal from salt solutions has been described using a metal hydroxide loaded ion exchange resin (1). DOWEX G-26 (H) strong acid cation exchange resin is a tough and versatile cation resin for this application.
Process Water/Wastewater: Under acidic conditions, halogens, and their complex oxides are acids and can be removed from solution with an acid absorber like DOWEX M-43 resin. Under neutral to basic conditions, DOWEX 21K XLT resin as the strong base functionality is needed to split the salt. For streams that have a high organic content and are prone to surface fouling, DOWEX MARATHON™ MSA strong base anion exchange resin is recommended. Anions are removed according to their selectivity as described in the table of selectivity data (82K PDF).
Acid Vapor Capture: Halogen acid gases cause corrosion problems in a wide variety of applications. For information on corrosion control, please see information relating to DOWEX M-43 resin.
Fluoride: For fluoride removal see the Fluoride page of the Periodic Table Product Selection Guide.
For Perchlorate Removal from Ground Water: See the Perchlorate removal page.
Removing Lubricants from Compressed Gases: Since halogen gases (X2) are often used in a compressed form, they are often contaminated with compressor lubricants. DOWEX OPTIPORE™ polymeric adsorbents have been shown to work well to remove these compressor lubricants from compressed gas streams (2).
References
1."Method of purification of salt solution for electrolysis", Oohara, C.; Matsuoka, T.; Kishi, T. and Okuno, T. of Chlorine Engineers Corp., Ltd. European Patent Application EP 0 987 221 A1 (1999).
2."Removal of oil from compressed gas with macroporous polymeric adsorbents" Bowman, R.H. and Goltz, H.R. US Patent 5,700,310, MG Generon, December 23, 1997.
The Group VIIA elements (fluorine, chlorine, bromine, iodine, astatine) are commonly referred to as halogens. Halogen atoms are characterized by an electronic structure where they are missing one electron so they readily form the anion X-. Halogens also form complexes like iodide I3- that are strongly anionic. Halogens form oxides and oxo-acids such as ClO2- and perchlorate (ClO4-) that again are anionic. |
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