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| Degradation of dipyrone in water by advanced oxidation processes and evaluation of the toxicity for the degradation products. |
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Abstract Dipyrone was depredated by UV, H2O2, UV/H2O2, Fenton, UV/Fenton and other advanced oxidation process in the laboratory scale, and the toxicity of the degradation products was evaluated. On the basis of optimized parameters (pH, H2O2 dosage, Fe2+ dosage, illumination time), the degradation effect was evaluated using removal effect of TOC and degradation of dipyrone. The toxicity of dipyrone and its photocatalytic intermediates in aqueous solution were assessed by the growth inhibition of Chlorella vulgaris and was showed by the 96h half effect of concentration (EC50). The degradation effect of UV/Fenton for dipyrone was most efficient, the optimized parameters were pH 3, Fe2+ 2mg/L and H2O2 140mg/L. Biological test showed that the intermediates were of more toxicity than the matrix compound because the EC50 value was minimum (13.65mg/L) when the reaction time reached 30min. With the reaction time increased the value of EC50 gradually increased, and reached 44.07 mg/L at 180 min, and the chlorella was grew well in good condition, which showing that photo-Fenton reaction was fit for degradation of low concentrations of dipyrone in aqueous solution and the treated water didn¢t have biological toxicity for chlorella.
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Received: 05 January 2009
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