Weak Base Anion Exchange Resins

Weak base anion (WBA) exchange resins contain primary, secondary, tertiary (most popular) amine functional groups attached to the polymer matrix and operate in the free base form and show different strengths of alkalinity. The weak base anion exchange resins does not split neutral salts but only react with strong acids such as hydrochloric acid (HCl), nitric acid (HNO₃) and sulfuric acid (H₂SO₄) and they are typically regenerated with sodium hydroxide (NaOH), ammonia (NH₃), or sodium carbonate (Na₂CO₃).

The Weak base anion (WBA) exchange resins can be classified based on their functional groups:

• Primary amine resins: Contain Primay amine groups (—NH₂)
• Secondary amine resins: contain secondary amine groups (—NHR)
• Tertiary amine resins: contain tertiary amine groups (—NR₂)
• Mixed base anion resin

Except that, The WBA exchange resins also have gel type and macroporous type, with an acrylic, polystyrene or mixed matrix.

• LX6702, Gel type, acrylic, mixed base anion resins
• MA939, Macroporous type, acrylic
• LSF930B, Macroporous type, polystyrene crosslinked with DVB, tertiary amine
• LSF9300, Macroporous type, polystyrene crosslinked with DVB, tertiary amine
• LSF930A, Macroporous type, polystyrene crosslinked with DVB, tertiary amine
• LSF907, Macroporous type, polystyrene crosslinked with DVB, tertiary/quaternary amine
• LSF67, Gel type, acrylic
• CM1670, Gel type, crosslinked acrylic, tertiary amine
• MA943, Macroporous type, tertiary amine
• LX6703, Macroporous type, acrylic, mixed base anion resins
• LSF973, Macroporous type, polystyrene crosslinked with DVB, tertiary/quaternary amine
• LSF962, Macroporous type, Styrene-divinylbenzene
• LSF9732, Macroporous type, Styrene-divinylbenzene, tertiary amine
• LSF976, Macroporous type, polystyrene crosslinked with DVB, tertiary amine, low strong base group

• Compared with Strong Base Anion (SBA) exchange resins, WBA exchange resins are easier to regenerate and can be effectively regenerated with a small amount of sodium hydroxide (NaOH).
• In addition, they have better chemical stability and higher resistant to organic fouling than SBA exchange resins.

• Weak base anion (WBA) resins are commonly used for partial demineralization processes. In large-scale systems, WBA resin beds are often integrated with strong base anion (SBA) units to achieve complete demineralization.
• Additionally, WBA resins serve as efficient total organic carbon (TOC) barriers when placed upstream of SBA beds, enhancing system performance.
• They are also employed for acid absorption, particularly in the removal of chloride, sulfate, nitrate, and other anions from strong acids.
• However, WBA resins are not effective in eliminating weak acids, such as silica (SiO₂) and carbon dioxide (CO₂).
• Typical applications are removal of mineral acid, removal of organic matters, pure water preparation and wastewater treatment.