Study Of Microchannel Process Enhancement Process For Aromatic Amine Dyestuff Production Wastewater

China is a major dyestuff producing country,and the dyestuff production wastewater is characterized by high production,high toxicity,high chromaticity and high COD.Most of the factories discharge the dyestuff production wastewater directly without adequate treatment due to the lack of environmental awareness,which causes serious harm to the environment.To address such problems,this thesis proposes a microchannel process to enhance the degradation of aromatic amine dyestuff production wastewater.The microchannel reactor is used as a reactor for wet oxidation through a combined process of Fenton oxidation and wet oxidation.This thesis is divided into（1）degradation of aniline simulated wastewater using Fenton oxidation and wet oxidation to investigate the effect of different process condition parameters on aniline removal rate.（2）To investigate the reaction mechanism of Fenton oxidation and wet oxidation for the degradation of aniline through the analysis of aniline degradation pathways.（3）Pretreatment of aromatic amine dyestuff wastewater using Fenton oxidation through degradation of actual dye production wastewater,and optimization of the process conditions for pretreatment of aromatic amine dye production wastewater by Fenton oxidation through single-factor experiments combined with response surface analysis.Then the Fenton pretreatment aromatic amine dye production wastewater effluent was degraded in depth using wet oxidation,characterized by COD removal rate.（3）The optimal process conditions for wet oxidation degradation of Fenton oxidation pretreatment aromatic amine dye production wastewater were explored based on the conditions of wet oxidation in a conventional kettle reactor,and process enhancement was carried out on this basis to investigate the process conditions of microchannel reactor as a wet oxidation reactor for Fenton oxidation pretreatment dye production wastewater effluent.Details of the study and conclusions are as follows.（1）Using Fenton oxidation and wet oxidation to degrade aniline simulated wastewater,the best process conditions for Fenton oxidation were obtained by single-factor experiments as aniline concentration=0.1 g/L,H₂O₂/Fe²⁺ratio of 9,V（H₂O₂）=1.2 mL,and pH=4,at which the aniline removal rate was 94%.The best process conditions for wet oxidation were3h reaction time,pH=2,1.2mL H₂O₂ addition,P=0.75MPa pressure,and T=210℃,when the best aniline removal rate was achieved.（2）Fenton oxidation was used in combination with wet oxidation to degrade aromatic amine dyestuff production wastewater,and the best combination of conditions was obtained by single-factor experiments with pH=1,C（H₂O₂）=1mol/L,V（H₂O₂）=40mL,and Fenton filler dosage=7 g.The process conditions of Fenton oxidation pretreatment of aromatic amine dyestuff production was optimized by combining response surface analysis.The optimal combination of conditions was initial pH=1.04,C（H₂O₂）=1.13mol/L,V（H₂O₂）=43mL and Fenton filler dosage=7.2g.The predicted maximum removal rate was 84.63%and the test result was82.93%,which deviated from the predicted value by only 1.7%.The optimal combination of wet oxidation conditions was a reaction time of 3h,pH=3.2,H₂O₂ addition of 1.2mL,pressure P=0.5MPa,and temperature T=215℃.（3）The optimal process conditions for the pretreatment of aromatic amine dye effluent using microchannels as reactors for wet oxidative degradation of Fenton oxidation were investigated.The optimal process conditions were pH=3.2,C（H₂O₂）=0.1 mol/L,flow rate ratio of wastewater to H₂O₂ solution of 1:1,residence time of 8 min,and reaction temperature of110℃.The maximum COD removal rate could reach 94.2%.With the addition of 120 mg/L of Ni²⁺,the COD removal rate was increased by 3.4%.