Abstract: A heterogenous hybrid thermally regenerable salt sorbent resin is formed from a hybrid precursor resin. The hybrid precursor resin is formed by intimately mixing a dry, solid crosslinked macroporous copolymer with a solution containing a polyunsaturated monomer, a monoethylenically unsaturated monomer containing a haloalkyl group and a polymerization initiator, followed by heating to cause polymerization. The hybrid precursor resin is then treated with a weak base, then subjected to hydrolysis conditions to form, respectively, weak base groups and weak acid groups to produce the hybrid thermally regenerable salt sorbent resin.

Abstract: An improved system of resins comprising a combination of a sulfate-specific strongly basic anion exchange resin and a heterogenous hybrid thermally regenerable salt sorbent (TRSS) resin is provided. The anion exchange resin contains triethylamine and/or tributylamine groups. The TRSS resin comprises a macroporous host copolymer and a crosslinked guest copolymer having, respectively, weak acid groups and weak base groups. The system is used to treat feed water containing dissolved ions, including sulfate ions, and is efficiently regenerated.