Cetyltrimethylammonium bromide (CTAB), a cationic quaternary ammonium surfactant, was found to be efficiently removed from aqueous solution by tannin resins from cypress, quebracho, pine and Weibull black [32]. A maximum adsorption capacity of 696 mg g1 (1.91 mmol g1) was reported under neutral pH, for a pine tannin gel.