Abstract
Two commercial anionic surfactants, namely sodium dodecylsulfate (SDS) and tetraethylammonium dodecylbenzenesulfonate (DBS), have been submitted to different oxidizing treatments: ozone, ozone at basic pH, sonication, ozone/sonication, ozone/hydrogen peroxide, UV, and UV/ozone. The best results were achieved with O3 /UV and O3 at basic pH where hydroxyl radical is generated; under these conditions, nearly complete elimination of the surfactant was achieved after 10 min of treatment (compared with 50% elimination of DBS and 20% of SDS in ozonation at acidic pH, where molecular O3 is the actual oxidizing agent). The total organic carbon decrease was only moderate and never exceeded 50%. On the other hand, surface tension increased to reach values close to that of distilled water (72 mN/m) in only 15 min of treatment, indicating that ozone is very useful to destroy the species having active surface properties.
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