Photocatalytic degradation of atrazine using zinc oxide texturally modified with sticky rice starch template and doped with transition metals

Pummarin Khamdahsag1, Nuttaporn Pimpha2, Raumporn Thongruang3, Nurak Grisdanurak4,5, Mark A. Nanny6, Jatuporn Wittayakun1

1 Suranaree University of Technology, School of Chemistry, Institute of Science, Nakhon Ratchasima 30000, Thailand
2 National Nanotechnology Center, National Science and Technology Development Agency, Thailand Science Park, Pathumthani 12120, Thailand
3 Thammasat University, Department of Physics, Pathumthani 12121, Thailand
4 Thammasat University, Department of Chemical Engineering, Pathumthani 12121, Thailand
5 Thammasat University, Center of Excellence on Environmental Catalysis and Adsorption, Pathumthani 12121, Thailand
6 University of Oklahoma,School of Civil Engineering and Environmental Science, Norman, Oklahoma 73019, USA


Atrazine is a herbicide used widely with a large quantity in Thailand and can contaminate in surface and groundwater. This work investigated atrazine removal from an aqueous solution by catalytic photodegradation using oxides of metal-cerium-zinc (M-Ce-ZnO, M = Ag, Fe, and Cu). ZnO is texturally modified with sticky rice starch template, doped with cerium (Ce) and either Ag, Fe, or Cu with the M:Ce:Zn molar ratio of 0.005:0.005:1. The catalysts were characterized by XRD, UV-Vis-DRS, and N2 adsorption-desorption analysis; and tested in a batch reactor under visible light. 0.005Ag-0.005Ce-ZnO exhibited a higher atrazine removal than 0.005Fe-0.005Ce-ZnO and 0.005Cu-0.005Ce-ZnO. Thus, a further investigation was carried out on 0.005Ag-0.005Ce-ZnO with various atrazine concentrations. The photocatalysis was explained by Langmuir-Hinshelwood-Hougen and Watson (LHHW) kinetics. The reaction rate constant was higher than the adsorption equilibrium constant indicating that the photocatalytic reaction was a key role in the atrazine removal. In the presence of humic acid, a representative of natural organic matter, a competition with atrazine was observed. To determine the degradation pathway, several intermediates were detected by liquid chromatography-mass spectrometry including 2-isopropylamino-1,3,5-triazine which was not previously reported. The efficiency of 0.005Ag-0.005CeZnO suggests a possibility for the application under the sunlight.


atrazine; metal doped ZnO; photocatalysis; sticky rice starch; textural modification

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