Photocatalytic removal of 2,4-dichlorophenoxyacetic acid by using sol-gel synthesized nanocrystalline and commercial TiO2: Operational parameters optimization and toxicity studies

摘要: Abstract A comparative study of the photoefficiency two different TiO 2 catalysts in elimination, mineralization and detoxification waters containing herbicide 2,4-dichlorophenoxyacetic acid (2,4-D) toxic intermediates was performed at laboratory scale. Commercial (Degussa (Evonik) P25) synthesized by citrate sol–gel method (ECT-1023t) were selected as photocatalysts. Adsorption studies, kinetic analysis an effect adding oxidizing agents (H O S 8 2− ) carried out for both catalysts. The photocatalytic treatment reaction times determined marine bacteria Vibrio fischeri bioassay. on this organism main degradation intermediate 2,4-dichlorophenol (2,4-DCP) higher than initial herbicide. optimal operational variables to eliminate established most effective removal 2,4-D 2,4-DCP achieved using ECT-1023t catalyst pH 3 5. inhibitory V. growth water after 2 h negligible when catalyst. Longer necessary obtain similar results P25 addition H significantly enhanced rate, with concentrations tested When agent, toxicity eliminated before 1 h photodegradation