PHOTODEGRADATION OF SURFACTANTS .15. FORMATION OF SO4(2)-IONS IN THE PHOTOOXIDATION OF SULFUR-CONTAINING SURFACTANTS

Three types of surfactants and related reference compounds containing sulfonate (-SO3Na), sulfate (-OSO3Na) or thioether carboxylate (-S-Cn-COOK) group were photodecomposed in an aqueous heterogeneous dispersion system. The photomineralization to SO4(2)-ions was examined for the surfactants with different chemical structures. The photocatalytic activities of TiO2 and ZnO were compared for the sulfonates of dodecylbenzene sulfonate (DBS) and polystyrene sulfonate (PSS), the sulfates of sodium dodecyl sulfate (SDS), and the potassium salts of S-dodecylthioglycol acid (TGA), S-dodecylthiopropionic acid (TPA) and S-dodecylthiomalic acid (TMA). ZnO catalyst exhibited higher activity in the formation of SO4(2)-ion than TiO2 catalyst.