Research On Treatment Of Dyeing Wastewater By Coagulation-fenton Process

This paper has summarized the current status and trend of dyeing wastewater treatment technologies, analyzed and discussed the mechanism of treating dyeing wastewater by coagulation and Fenton oxidation.This study with water-soluble dye alizarin red, methyl red dye dispersion solution configured as a simulated dyeing wastewater, The dyeing wastewater is treated by Fenton oxidation process after coagulation pretreatment. Through analyzing single factor experiments ,the realation curve were obtained ,which between influence factors and COD_Cr removals by coagulation and Fenton reagent process system .The effecting factors on the coagulation, such as the type and dosage of coagulant, pH, temperature, stirring speed and time were studied,while the various effecting factors on the Fenton's oxidation process, such as H₂O₂ dosage and dosing method, Fe²⁺ dosage, pH, temperature, reaction timeand UV were studied, It is also compared with the Fenton reagent oxidation coagulation on removal of two different dyes, and analysis of its causes.The results show that, The best conditions for coagulation are as follows: in the alizarin red solution, adding of PAC=300mg/L; adding of PAM=10mg/L; pH=10; T=40℃; fast mixing 2min; slow stirring 15min; in the methyl red solution, adding of PAC=50mg/L; adding of PAM=2mg/L; pH=10; T=40℃; fast mixing 2min; slow stirring 15min; The best conditions for Fenton are as follows: in the alizarin red and methyl red solution, adding of H₂O₂=0.5mL/L; adding of [Fe²⁺]=150mg/L; pH=3; T=30min. after coagulation-Fenton reagent oxidation process, in their optimum conditions, the degradation rate of two dyes have achieved some results, degree of water-soluble dye and alizarin red COD_Cr removal rate of 88.2%, 79.6%, methyl red dye dispersion degree and COD_Cr removal rate of 75.3%, 70.1%.