A method of capturing a basic, nitrogen-containing compound is provided. The basic, nitrogen-containing compound is captured by sorption (e.g., adsorption) on a sulfonic-acid containing polymeric material. The sulfonic acid-containing polymeric material is formed from a polymerizable composition that contains a free-radically polymerizable spirobisindane monomer. Additionally, a polymeric material is provided that is a reaction product of a sulfonic acid-containing polymeric material having at least one —SO3H group and a basic, nitrogen-containing compound of formula Q. This polymeric material has at least one group of formula —SO3−(QH+).