DIAION HPA25

Summary

Product Identification

The DIAION HPA Series comprises Strongly Basic Anion Exchange Resins (SBAERs). These resins are designed to exchange anions such as Cl⁻ and SO₄²⁻.

There are two types of SBAERs:

• Type I: Features trimethylammonium groups (R-N⁺(CH₃)₃) as ion exchange groups. DIAION™ SA10A and SA20A are typical products of this type, characterized by high basicity and strong anion adsorption.
• Type II: Features dimethylethanolammonium groups (R-N⁺(CH₃)₂·CH₂CH₂OH) as ion exchange groups. Type II resins exhibit slightly weaker basicity compared to Type I.

Product Description

SBAERs possess quaternary ammonium groups (N⁺) as their functional groups, which exhibit strong basicity similar to inorganic bases like NaOH or KOH. These functional groups are strongly basic and dissociate in both acidic and alkaline solutions, forming N⁺OH⁻. SBAERs can exchange counter ions even with neutral salts and weak acids such as silicic and carbonic acids, making them ion-exchangeable across the entire pH range.

Regeneration of SBAERs is typically performed using 4% NaOH aqueous solutions. Weakly basic NH₄OH is generally insufficient for effective regeneration. The regeneration reaction for a Cl⁻ form SBAER is shown as:

R-N⁺Cl⁻ + NaOH → R-N⁺OH⁻ + NaCl

Due to their strong basicity, SBAERs require a greater amount of regenerant than the theoretical amount for complete regeneration.

Applications

DIAION™ SA10A and SA20A (Type I) are used for producing high-grade demineralized water due to their high basicity and strong anion adsorption. While effective, their strong adsorbability necessitates significant regenerant use. Type II resins, while producing demineralized water of slightly lower quality compared to Type I, offer reduced regenerant consumption.

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Official datasheet (PDF)

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