Photocatalytic degradation of atrazine by H3PW12O40/Ag–TiO2: Kinetics, mechanism and degradation pathways

• H3PW12O40/Ag–TiO2 catalyst exhibited excellent degradation efficiency towards AT.
• The influencing factors on degradation kinetics of aqueous AT were studied in detail.
• The hydroxyl radicals was the major reactive oxygen species during the AT degradation.
• The possible AT photodegradation pathways using H3PW12O40/Ag–TiO2 were proposed.

A series of experiments were conducted to investigate the kinetics of atrazine (AT) degradation, photocatalytic degradation mechanism and degradation pathways using H3PW12O40/Ag–TiO2 as photocatalyst. The effects of experimental parameters including catalyst amount, initial concentration of the substrate, and solution pH value on AT degradation rates were evaluated. The results showed that the removal of AT followed a pseudo-first-order reaction kinetic. The highest photocatalytic degradation efficiency was obtained using H3PW12O40/Ag–TiO2 (19.7, 0.8) with catalyst amount of 1.0 g L−1 and AT initial concentration of 5 mg L−1 at pH value of 3.4. The investigation of photocatalytic mechanism indicated that hydroxyl radical (OH) was the major reactive species for the photocatalytic reactions of AT compared with photohole (h+). Ten photoproducts were observed during the AT photodegradation process. Based on the identified intermediates, two tentative degradation pathways for the photocatalytic degradation of AT were proposed.

A series experiments were conducted to investigate the kinetics of AT degradation using H3PW12O40/Ag–TiO2 composite catalyst, photocatalytic-oxidation mechanism and degradation pathways of AT. The studies will promote the technical development for AT removal, and might open up new opportunities for H3PW12O40/Ag–TiO2 simulated sunlight-induced photocatalysis in the practical application of photocatalytic degradation organic pollutants.Figure optionsDownload as PowerPoint slide