Preparation of crosslinked poly(styrene–g–N‐carboxyalkylated ethylenimine) as chelating resin

Carboxymethyl and ethyl groups were introduced into crosslinked poly(styrene–g–ethylenimine) (PSt–g–EI), consisting of a crosslinked polystyrene backbone with linear polyethylenimine branches, by the reaction of PSt–g–EI with monochloroacetic acid and β‐chloropropionic acid. Carboxyethylation was also performed by reaction of the PSt–g–EI with acrylic acid. The extent of the reaction was determined by the change in the nitrogen content of the resin. The adsorption of metal ions such as Cu2+, Cd2+, Hg2+, Ni2+, and Ca2+ by carboxyalkylated PSt–g–EI was examined. With the introduction of carboxyalkyl groups, the adsorption capacity for metal ions (per gram of resin) decreased, whereas the affinity of the resin for these ions increased.