Patent ID: 7875186

Claim:
A process for regenerating and protonating exhausted weak-base anion exchange resins, wherein the process is capable of minimizing the volume of regenerating solution and chemicals required for regeneration, said process comprising the steps of: a. providing an exhausted weak-base anion exchange resin; b. regenerating said exhausted weak-base anion exchange resin by a process consisting of the steps of: i. providing a batch of caustic regenerating solution; ii. circulating the batch of regenerating solution through said exhausted weak-base anion exchange resin to neutralize ion exchange sites on the resin, convert the resin to a free-base form, and elute anions from the resin to provide a regenerated resin, by (1) passing the batch of regenerating solution over the resin, (2) capturing the regenerating solution passed over the resin, (3) passing the captured regenerating solution over the resin, and (4) repeating steps (2) and (3), wherein said steps are performed in a closed-loop manner, without the addition of water or base to the captured regenerating solution until the resin is regenerated; and c. protonating said regenerated resin by a process comprising the steps of: i. providing a batch of acidic protonating solution; and ii. circulating the batch of acidic protonating solution through the regenerated resin to restore the resin to an ionized, active form, wherein no additional batches of caustic regenerating solution are added between steps a and b.