Date

2019

Author

Ulu, Hatice Bike

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Chloridazon (5 -amino-4- chloro-2-phenyl-3(2H)-pyridazinon), also named as Pyrazon and classified as organochlorine pesticides, is widely used during sugar beets cultivation. Chloridazon (CLZ) being a pesticide with a high solubility in water is likely to end up in surface and groundwater bodies because of its high mobility in soil. Due to its toxic properties, it may cause serious problems on human health and ecological cycle. In the present study, the removal of CLZ herbicide from water was investigated by means of Advanced Oxidation Processes (AOP’s), namely UV/H2O2, Fe/H2O2 (Fenton) and UV/Fe/H2O2 (Photo-Fenton). The effect of operational parameters such as initial CLZ concentration, H2O2 concentration, Fe concentration, pH and temperature were sought. It was observed that CLZ completely disappeared within 1 h by the Fenton and UV/H2O2 processes while in the Photo-Fenton processes approximately 100% disappearance was observed in 20 minutes, under optimum conditions. The optimum conditions were determined as 20 mg/L H2O2, 20 mg/L initial CLZ, pH 3 and 20oC for UV/H2O2 process; 7.5 mg/L Fe2+, 50 mg/L H2O2, 40 mg/L initial CLZ, pH 3 and 20oC for Fenton process, and 5 mg/L Fe2+, 50 mg/L H2O2, 60 mg/L initial CLZ, pH 3 and 20oC for Photo-Fenton process. Desphenyl CLZ, Pyridazine-3,4,5-trione, Oxaluric acid and 5-hydroxyhydantion were identified as CLZ degradation by-products. Accordingly, degradation pathway was proposed for each process. The reaction kinetics of CLZ followed pseudo-first-order kinetics in case of UV/H2O2 while BMG (Behnajady-Modirdhahla-Ghanbery) kinetic model was followed in case of Fenton and Photo-Fenton processes.

Subject Keywords

Pollutants., Water, Factory and trade waste., Sewage

URI

http://etd.lib.metu.edu.tr/upload/12623055/index.pdf
https://hdl.handle.net/11511/28001

Collections

Graduate School of Natural and Applied Sciences, Thesis