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有机废水的催化降解基础研究

Study on Catalytic Degradation of Organic Wastewater

【作者】 丁小红

【导师】 陶长元;

【作者基本信息】 重庆大学 , 物理化学, 2008, 硕士

【摘要】 有机废水由于其强毒性、难降解、分解易产生致癌物,被视为当今急待治理的废水之一。近年来,迅速发展起来的催化降解技术,在有机废水处理上展现出良好应用前景。本文对廉价粉煤灰、改性空心微珠催化降解有机废水进行了较为全面的研究,为有机废水治理提供了新方法和新途径。本论文开展了以下三个方面的工作:(1)研究了微波作用下粉煤灰催化H2O2降解甲基橙模拟废水动力学行为,并对甲基橙降解机理进行了分析。(2)针对实际有机废水---1,2,4-氧体废水和垃圾渗滤液,研究了微波作用下粉煤灰催化H2O2降解实际有机废水的行为和能力。(3)以改性空心微珠为催化剂,在探讨Fe/Ni比、微波、离子液体对改性影响的基础上,研究了其催化降解甲基橙溶液的性能和动力学行为。粉煤灰用量、H2O2用量、初始pH对甲基橙溶液降解效果的影响与Fenton氧化法的影响趋势大致相同;微波作用可提高处理效率,减少试剂用量。对于100mL1000mg/L的甲基橙溶液,在pH为2、粉煤灰用量1g、30%H2O2用量1mL、微波作用时间4min、微波功率800W、温度100℃时,脱色率达99.8%,COD去除率达80%。粉煤灰可回收再利用2~3次,从而减少粉煤灰大量堆积造成的二次污染。粉煤灰吸附甲基橙的行为满足Langmuir方程1/qt=4.139+0.007 3/Ce。微波作用下粉煤灰催化H2O2氧化过程更符合Fenton反应机理的一级反应动力学模型lnCt=-0.772 1t+7.016,反应速率常数为0.772 1/min。微波作用下粉煤灰催化H2O2处理实际废水是有效的。在降解高浓度1,2,4-酸氧体废水中,对于100mL废水,粉煤灰用量6g、30%H2O213mL、微波辐射时间5min、微波功率800W、温度80℃时,COD去除率可达80.3%。在应用该方法对垃圾渗滤液的处理中,当粉煤灰量为20g/L、pH为2、搅拌5min后过滤分离;100mL滤液加入2mL30%H2O2,设定微波温度80℃、功率600W,在微波中作用20min后,COD的去除率可达69.81%。通过对改性空心微珠降解性能的研究表明,离子液体存在下改性的Fe/Ni比为1:3的空心微珠,在处理1 000mg/L甲基橙溶液时,对甲基橙的去除率为94.52%。甲基橙的催化降解较好的遵循了Langmuir-Hinshelwood动力学模型1/r0=(1709.1/C0)+6.237 5,催化反应速率常数k为9.62mg/(L·h),吸附常数K为3.65×10-3L/mg。

【Abstract】 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.

  • 【网络出版投稿人】 重庆大学
  • 【网络出版年期】2009年 06期
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