Study On Catalytic Degradation Of Organic Wastewater

Persistent organic pollutants (POPs) are regarded as high toxic, refractory and carcinogen, which become a headache to the public. Hence, to purify the POPs with new technologies is in need. In the present, catalytic degradation for POPs shows good application potential. The present work is focused on the catalytic degradation process with cheap fly ash and modified cenosphere.The work done includes: (1) Kinetic behavior and mechanism for degeadation of methyl orange solution with microwave assisted H₂O₂ of fly ash, (2) application of this process to purify industrial waste water from manufacutring of 1-diazo-2-naphthol-4-sulphonic acid and landfill leachate from municipal. Feasibility and behavior of degradation of true waste water was studied with Microwave-fly ash-H₂O₂ system, (3) degradation performance and dynamic model for methyl orange solution with modified cenospheres by microwave-ionic liquid system.Some interesting results are obtained from the experimental investigation. The varation trend of degradation of methyl orange solution with Fenton reagent is similar to that of Fenton-like reagent of fly ash-H₂O₂. Microwave irridation can reduce the consumption of regent and improve the degradation performance. the decolorization and COD removal ratios were 99.8% and 80%, respectively, for the 100mL 1000mg/L MO solution, under the operation conditions of pH 2, fly ash 1.0 g, 30% H₂O₂ 1.0 mL, microwave power 800 W for 4 min at 100℃. Fly ash deactivation was found after 2-3 times reuse and it contriutes to reduce much sludge, which can inhibit secondary pollution. The adsorption behavior of fly ash meets Langmuir isotherm equation 1/qt=4.139+0.007 3/Ce. But the catalyst process of microwave-fly ash-H₂O₂ system agrees with Fenton reaction mechanism well, namely first order reaction kinetics mode lnCt=-0.772 1t+7.016, and the reaction rate constant is 0.772 1/min.It is feasible to degrade industrial wastewater from manufacturing of 1-diazo-2- naphthol -4-sulphonic acid in microwave-fly ash-H₂O₂ system. COD removal ratios was 80.3% under the condition of 6% of fly ash, 13% H₂O₂ (mass percent 30%), at 800 W and 80℃for 5 min. While in landfill leachate treatment, COD removal ratios was 69.81% at pH 2 and 2% fly ash at 600 W and 80℃for 20 min.For the modified cenosphere catalyst with ionic liquid at Fe/Ni ratio 1:3, decolorization removal ratio was 94.52% for methyl orange solution at 1000 mg/L. The catalytic degradation of methyl orange solution follows Langmuir-Hinshelwood model 1/r₀=(1 709.1/C₀)+6.237 5, the reaction rate constant k is 9.62 mg/(L·h), and adsorption constant K is 3.65×10^-3L/mg.