Fe基非晶合金对亚甲基蓝和乙酸的催化降解研究

论文总字数：30216字

摘 要

随着化学工业的高速发展，有机化学品种类增加，出现了很多毒性大、生物稳定的有机污染物。异相Fenton氧化技术与均相Fenton技术相比，具有PH适用范围更宽、H₂O₂利用率更高和催化剂能回收利用等优点，已经成为Fenton氧化技术发展的方向，也为印染废水的处理提供了一条高效的途径。在降解这些污染物时，Fe基非晶合金是否同样具有优异的效果，目前还并不清楚，需进一步进行研究。

本文采用非晶作为Fenton体系的催化剂，将非晶优秀的催化性能和Fenton法结合起来对亚甲基蓝溶液进行催化降解，并且得出了重要结果：（1）首先，利用非晶作为Fenton催化剂对亚甲基蓝水溶液降解是非常有效的，并且将Fenton试剂适用的PH值提高到4。（2）对非晶Fenton反应对降解亚甲基蓝溶液的反应动力学进行了分析，得出了动力学方程和动力学参数。（3）对用作催化剂的非晶种类进行了探究，发现Fe₈₅Hf₅B₁₀的效果最好，6min的降解率就能达到90%以上。（4）在PH=4时，经回收的非晶再次用作催化剂时，降解效果得到明显提高，同样的实验条件下第二次使用时，5min的降解率能达到95%以上。

在研究非晶Fenton体系对亚甲基蓝溶液的降解过程中，本实验采用控制变量的方法对各个影响因素进行逐一探究，最终得出了降解发生的最优条件：常温下，亚甲基蓝溶液浓度为10mg/L，调节PH=4，H₂O₂的浓度为2mM，Fe₇₈Si₉B₁₃非晶的加入量为0.1g/L时，15min的降解率能达到90%以上。在对温度进行探究的过程中，发现在35℃时催化降解的效果最好，但从工艺方面考虑，25℃（常温）既改善了降解效果又兼顾了使用成本，因此25℃是最优选择。

对Fenton体系对亚甲基蓝溶液降解过程的动力学过程进行了分析，发现当PH小于5时，反应符合一阶反应动力学。本实验对非晶合金和退火态合金的催化降解效果进行了对比，发现在常温下，非晶的降解效果明显优于退火态合金，当温度升高时，两者的降解效果的差别渐渐缩小。对两组实验的动力学常数进行计算时，发现采用非晶进行降解时的反应活化能明显低于退火合金。

对非晶重复利用的次数进行的研究表明，非晶重复利用作为催化剂的效果要明显高于第一次使用。通过X射线衍射和扫描电子显微镜等手段，发现使用后的非晶表面的氧化物和经反应留下的坑蚀是降解效果提高的主要原因，但反应前后，非晶结构并没有发生变化。

关键词：异相Fenton法、铁基非晶、亚甲基蓝、催化降解

Catalytic degradation of methylene blue using Fe-based amorphous alloy

Abstract

With the rapid development of chemical industry, organic chemicals are increasing, and there are many toxic and organic pollutants. Compared to homogeneous Fenton oxidation process, heterogeous Fenton oxidation process has the advantages of higher utilization of H₂O₂, wider range of PH, easier recovery and so on. It provides an effective way for the treatment of printing and dyeing wastewater.. In the degradation of these contaminants, whether Fe-based amorphous alloys has the better degradation effect needs further study.

Using amorphous alloy as Fenton catalyst, this study combines the excellent catalytic performance of amorphous alloy and Fenton oxidation process to finish the catalytic degradation of methylene blue. And some new results are drawn. First of all, the use of amorphous alloy as Fenton catalyst for the degradation of methylene blue in aqueous solution is very effective, and the needed pH value is increased to 4. Secondly, the reaction kinetics of the degradation of methylene blue was studied, and the kinetic parameters were obtained. . Also, the effects of composition and repeated use of Fe-based amorphous alloy on the degradation process were studied.

In the study of the degradation of methylene blue solution by the amorphous Fenton reagent, the method of controlling variables was used to explore the influence factors. Finally the best conditions for the occurrence of degradation are grasped. At room temperature, the initial concentration of methylene blue solution is 10mg/L, PH value is 4, the concentration of hydrogen peroxide is 2mM, the addition of Fe₇₈Si₉B₁₃ is 0.1g/L, more than 90% methylene blue can be degraded within 15min. In the inquiry process of temperature, we found at the best degradation of methylene blue solution at 35℃. Combining the degradation effect and the cost, the temperature of 25 ℃ (room temperature) is optimal choice.

The kinetics of Fenton reaction for the degradation process of methylene blue was analyzed, and we found that, when the pH value is lower than 5, the reaction follows the first-order reaction kinetics. Experiments of the degradation by amorphous alloy and annealed alloy were also conducted. Results show that amorphous alloy has the better degradation effect than that ofannealed alloy at room temperature. However, when the temperature rises, the difference between degradation rate for the two alloys gradually reduced. The kinetic constants of two experiments were calculated and we found the activation energy of the reaction for amorphous alloy was much lower.

The study of repeated use of amorphous alloy shows that the degradation effect was improved after the first use. By X-Ray Diffractionand Scanning Electron Microscopy analysis, the iron oxides and pitting corrosion of the alloy surface after the first useis the main reason for enhancing the degradation effect. The structure of the amorphous alloy did not change after the reaction.

KEYWORDS: Fe based amorphous alloy, Heterogeous Fenton, Methylene blue, Catalytic degradation

目录

摘 要 I

Abstract II

第1章 绪论 1

1.1 我国水资源与污染现状 1

1.2 印染废水处理现状 1

1.2.1 印染废水的来源及危害 1

1.2.2 印染废水的主要特点 2

1.2.3 印染废水的研究现状及主要处理技术 2

1.3 Fenton氧化技术 4

1.3.1 Fenton法介绍 4

1.3.2 Fenton法的原理和影响因素 4

1.3.3 研究现状及存在问题 5

1.4 异相Fenton氧化技术 6

1.4.1 异相Fenton法介绍 6

1.4.2 研究现状及存在问题 6

1.5 铁基非晶 6

1.5.1 铁基非晶的介绍 6

1.5.2 铁基非晶用于催化剂的研究现状 7

1.6 课题研究目的意义和主要内容 7

1.6.1 研究目的和意义 7

1.6.2 主要研究内容 7

1.6.3 主要技术路线 9

第2章 实验仪器、材料和实验方法 10

2.1 实验仪器与药品 10

2.1.1 实验仪器 10

2.1.2 实验材料 10

2.2 实验操作方法 11

2.2.1 实验物品的准备 11

2.2.2 实验过程 11

2.3 分析测试方法 11

2.3.1 亚甲基蓝可见光吸收光谱 11

2.3.2 亚甲基蓝溶液脱色率测定方法 12

2.3.3 非晶结构和性能的研究 12

第3章 非晶Fenton反应对亚甲基蓝水溶液降解效果的影响因素探究 14

3.1 亚甲基蓝脱色的影响因素探究 14

3.1.1 不同反应条件下的降解效果对比 14

剩余内容已隐藏，请支付后下载全文，论文总字数：30216字