基于铁酸盐尖晶石的硫酸根自由基氧化体系在降解喹啉中的研究

发布时间：2018-07-04 10:41

  本文选题：铁酸盐尖晶石 + 硫酸根自由基　； 参考：《内蒙古大学》2017年硕士论文

【摘要】：喹啉在制药、印染、化工等行业普遍存在,是一种非常重要的精细化工原料。然而,如果将其释放到环境中,对动植物均会造成严重的毒害作用。在煤气化废水中,喹啉类化合物浓度可达40mg/L以上,是仅次于苯酚类的第二大污染物。因其有毒有害、生物抑制性强,传统生化处理法无法对废水中存在的喹啉实现有效降解,因此,使用高级氧化法成为处理此类废水的发展趋势。在高级氧化法中,硫酸根自由基氧化体系因其具有氧化性强、氧化速率快、pH适用范围广、选择性低等特点逐渐脱颖而出。目前,关于硫酸根自由基的研究主要集中在高效催化剂的制备、催化剂的可回收性和重复利用率的提高、催化机理的揭示等方面。在此背景下,本研究提出使用非均相硫酸根自由基体系降解喹啉的思路。具体研究内容包括:磁性尖晶石催化剂的制备、表征及催化活性评价;提高催化剂稳定性及可重复利用率的研究;催化机理研究;在降解喹啉时的效能的研究。研究结果表明,使用溶胶凝胶法制备的MFe2O4(M=Co、Mn、Cu、Zn)四种催化剂中,铁酸锰的催化效果最好。在煅烧温度为350℃时,生成的铁酸锰结晶完整,粒径较小,表现出很好的催化效果与稳定性。在铁酸锰尖晶石的硫酸根自由基氧化体系中,降解甲基橙的最佳的反应条件为:催化剂投加量1g/L、K2S2O8投加量为1g/L,此时甲基橙的降解率在90min时达到了 87.53%。催化剂的重复利用率表现优越,重复使用8次后甲基橙的降解率仍然在80%以上。另外,催化剂溶出率与催化效果有一定的相关性。通过竞争动力学的方法对所生成的自由基进行定性分析,发现在铁酸盐尖晶石的硫酸根自由基氧化体系中,SO4·-起着主导的作用,·OH次之。使用紫外-可见光全波长扫描来分析甲基橙的降解过程,发现甲基橙中的大共轭体-N=N-在反应的过程中发生断裂,溶液脱色,并且甲基橙中的苯环也被SO4·-攻击,生成了小分子化合物。在降解喹啉的实验中,最优的反应参数为:pH=7,K2S2O8的投加量为5g/L,催化剂的投加量为1g/L,室温。此时,在反应时间为60min条件下,喹啉的COD去除率可稳定达到了83.56%。本项目的开展,为深入理解过硫酸盐活化剂的制备及活化机理提供理论支持,为进一步阐明含喹啉废水降解机理及催化反应动力学提供了数据支撑,为高效率、低成本地处理含喹啉废水提供了新的途径,因此,具有重要的理论价值及实践意义。
[Abstract]:Quinoline is widely used in pharmaceutical, printing and dyeing, chemical industry and so on. It is a very important fine chemical raw material. However, if released into the environment, it can cause serious toxicity to animals and plants. In coal gasification wastewater, the concentration of quinoline compounds can reach more than 40 mg / L, which is the second largest pollutant after phenol. Because of its toxic and harmful, strong biological inhibition, the traditional biochemical treatment method can not achieve the effective degradation of quinoline in wastewater, therefore, the use of advanced oxidation process has become the development trend of treatment of such wastewater. In the advanced oxidation process, the sulfate radical oxidation system has the characteristics of strong oxidation, fast oxidation rate and wide range of pH application, low selectivity and so on. At present, the research of sulfate radical mainly focuses on the preparation of high efficient catalyst, the improvement of the recoverability and reutilization efficiency of catalyst, and the revelation of catalytic mechanism. Under this background, the idea of using heterogeneous sulfate radical system to degrade quinoline was put forward. The specific research contents include: preparation, characterization and catalytic activity evaluation of magnetic spinel catalyst; study on improving the stability and repeatability of the catalyst; study on the catalytic mechanism; and study on the efficiency in the degradation of quinoline. The results show that manganese ferrate has the best catalytic effect among the four kinds of catalysts prepared by sol-gel method. At the calcination temperature of 350 鈩，

本文编号：2095807