Visible light photocatalytic ozonation of DEET in the presence of different forms of WO3

• Different WO3 materials for visible light photocatalytic ozonation of DEET.
• Synergistic effect between ozone and irradiated WO3 with visible light.
• Higher efficiency of monoclinic/orthorhombic WO3 vs. hexagonal structure.
• Beneficial effect of W reduced states in the presence of ozone.
• Complete removal of DEET in 20 min and 70% mineralization in 120 min.

This work deals with the use of WO3 materials for the removal of DEET, an emerging contaminant, through photocatalytic ozonation using visible light as radiation source. A commercial WO3 and own-made WO3 catalysts with different forms and crystalline structure were synthetized by sol–gel and hydrothermal methods. After catalyst characterization with different techniques, photocatalytic ozonation under visible light radiation was found an efficient process to remove DEET. Monoclinic and/or orthorhombic structure of WO3 seems to favor the catalytic activity more than a developed surface area together with the presence of W reduced states in the presence of ozone. The best catalysts lead to a complete removal of DEET in less than 20 min with mineralization up to 70% in 2 h.

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