Selective adsorption of cationic surfactants on crosslinked poly(p-hydroxystyrene)

Cross-linked poly(p-hydroxystyrene) (PHSresin) was found to be an excellent and selective adsorbent for cationic surfactants in aqueous solution. Its adsorption capacity was remarkably higher than those observed with cation-exchange resins and porous resins not possessing an ion-exchange functional group. In addition, its adsorption capacity was not reduced by the presence of hydrochloric acid, sodium hydroxide, or sodium chloride and other inorganic salts. Elution of the adsorbed surfactants from PHS resin was easily accomplished by treatment with methanol, and the resin was effectively regenerated, in sharp contrast to adsorption on conventional cation-exchange resins. Cationic surfactants were concentrated into about 10 wt% solution in methanol