摘 要

粉煤灰是以煤为能源发电厂产生的废弃物，类Fenton技术具有降解效率高、原料廉价、应用范围广等优点。本文基于“国创”项目《Na₂S₂O₈改性TiO₂光催化法处理垃圾渗滤液的研究》，通过研究制备改性粉煤灰复合多羟基铁/粘土新型非均相催化剂材料，并对其合成工艺进行研究，以水中亚甲基蓝和垃圾渗滤液为处理对象进行降解污染物实验，详细研究了催化剂制备条件如粉煤灰与10 mmol Fe/g海泡石质量配比对降解效果的影响，获得最佳的催化剂制备条件和反应条件，并对该Fenton催化剂降解化工厂有机工业废水机理进行初步分析。所得结果对于新型Fenton法处理工业废水以及粉煤灰的资源有效利用具有重要的指导意义。主要结论如下：

（1）制备了改性粉煤灰复合多羟基铁/粘土新型非均相Fenton催化剂。利用2 mol/L的NaOH溶液、HCl溶液对粉煤灰进行酸碱改性，然后以初始浓度为0.05mol/L的有机物EDTA对粉煤灰进行水热活化改性。研究表明，经过改性后的粉煤灰成分结构和比表面积得到改善，更加有利于后续的催化反应；采用简易的浸渍方法，在低温（70°C）下制备了多羟基铁/海泡石催化剂，同时将经过酸碱改性、EDTA水热活化改性后的固体废弃物粉煤灰与10 mmol Fe/g 海泡石以质量比1：1、1：2、2：1混合，通过离心分离沉淀并用去离子水洗涤，经过预挤、成型后，将成型的催化剂在120℃干燥、600℃煅烧5h合成了改性粉煤灰复合多羟基铁/海泡石新型非均相催化剂。

（2）研究了所制备的催化剂用于处理水中亚甲基蓝和垃圾渗滤液效果。以亚甲基蓝溶液为处理对象预实验，探究了改性粉煤灰复合多羟基铁/海泡石非均相催化剂活化过硫酸盐对亚甲基蓝的处理能力，按照单一变量法和对照组实验得到当粉煤灰与催化剂配制比为1:2时，经过两个小时的光催化反应，亚甲基蓝的吸光度降低了60以上，其COD去除率达到了82.3%，得出1:2为粉煤灰与10 mmol Fe/g 海泡石为最佳质量比。原始水样来自武汉市陈家冲垃圾填埋场取得的BBR系统处理过后的垃圾渗滤液渗滤液，经检测出水 COD＜1000mg/L，BOD5＜200mg/L，NH3-N＜10mg/L，TN＜150mg/L；以制备的多羟基铁/海泡石非均相催化剂活化过硫酸盐进行降解实验绘制出哈希消解法标准曲线，而后实验组选用粉煤灰与催化剂配制比为1:2的复合催化剂，对200mL的垃圾渗滤液进行处理，对照组单独使用多羟基铁/海泡石非均相催化剂对200mL的垃圾渗滤液进行处理。根据实验结果，实验组在进行80min后，COD去除率便已到达95.10%，而对照组为58.27%。充分表明，以1：2质量比配制的改性粉煤灰复合多羟基铁/海泡石催化剂具有很高的催化性能。

（3）结合前人的相关成果，机理研究表明，所制备的改性粉煤灰复合多羟基铁/海泡石催化剂综合了H-Fe-S催化剂和载铁粉煤灰基复合催化剂的优点，因此产生了更加显著的催化降解有机物性能。

关键词：粉煤灰复合催化剂；可见光降解；非均相Fenton催化剂；类Fenton法

Abstract

Fly ash is a kind of waste produced by coal-fired power plants. Fenton like technology has the advantages of high degradation efficiency, cheap raw materials and wide application. Based on the project "Research on the treatment of landfill leachate by Na₂S₂O₈ modified TiO₂ photocatalysis, this paper studies the preparation of a new heterogeneous catalyst material of modified fly ash composite polyhydroxy iron / clay, and studies its synthesis process. Taking methylene blue in water and landfill leachate as the treatment objects, the pollutant degradation experiment is carried out, and the preparation conditions of catalyst are studied in detail The effect of the mass ratio of fly ash and 10 mmol Fe / g sepiolite on the degradation effect, the best catalyst preparation conditions and reaction conditions were obtained, and the mechanism of degradation of chemical plant organic industrial wastewater by Fenton catalyst was analyzed. The results have important guiding significance for the new Fenton process to treat industrial wastewater and the effective utilization of fly ash resources. The main conclusions are as follows:

(1) A new heterogeneous Fenton catalyst of modified fly ash composite polyhydroxy iron / clay was prepared. 2 mol / L NaOH solution and HCl solution were used to modify fly ash with acid and alkali, and then EDTA with initial concentration of 0.05 mol / L was used to modify fly ash with hydrothermal activation. The results show that the structure and specific surface area of the modified fly ash are improved, which is more conducive to the subsequent catalytic reaction; the polyhydroxy iron / sepiolite catalyst is prepared at low temperature (70 ° C) by simple impregnation method, and the solid waste fly ash modified by acid-base and EDTA hydrothermal activation and 10 mmol Fe / g Sepiolite was precipitated by centrifugation and washed with deionized water. After pre extrusion and molding, the catalyst was dried at 120 ℃ and calcined at 600 ℃for 5 hours to synthesize the modified fly ash composite polyhydroxy iron / clay heterogeneous catalyst.

(2) The effect of the catalyst on the treatment of methylene blue and landfill leachate was studied. The pretreatment experiment of methylene blue solution was carried out to explore the treatment capacity of modified fly ash composite polyhydroxy iron / Sepiolite heterogeneous catalyst to activate persulfate for methylene blue. According to the single variable method and the control group experiment, when the ratio of fly ash to catalyst was 1:2, after two small-scale photocatalytic reactions, the absorbance of methylene blue decreased by more than 60, and its COD removal rate reached 82.3 %1:2 is the best mass ratio of fly ash and 10 mmol Fe / g sepiolite. The original water sample comes from the leachate of landfill leachate after treatment by BBR system obtained from Chenjiachong landfill in Wuhan City, and the effluent is tested COD ＜ 1000mg / L, BOD₅ ＜ 200mg / L, NH₃-N ＜ 10mg / L, TN ＜ 150mg / L; the standard curve of hash digestion method was drawn by the prepared heterogeneous catalyst of polyhydroxy iron / sepiolite, and then the composite catalyst with the ratio of fly ash and catalyst of 1:2 was selected in the experimental group to treat 200ml of landfill leachate, and the control group used the heterogeneous catalyst of polyhydroxy iron / Sepiolite alone chemical agent is used to to activate persulfate for treating 200 mL landfill leachate. According to the experimental results, after 80 minutes, the COD removal rate of the experimental group has reached 95.10%, while that of the control group is 58.27%. The results show that the catalyst with 1:2 mass ratio has high catalytic performance.

(3) Combined with the previous achievements, the mechanism research shows that the prepared modified fly ash composite polyhydroxy iron / Sepiolite Catalyst combines the advantages of H-Fe-S catalyst and iron-loaded fly ash based composite catalyst, so it has a more significant catalytic degradation of organic compounds.

Key Words: fly ash composite catalyst; visible light degradation; heterogeneous Fenton catalyst；Fenton like method

目 录

第1章 绪论 3

1.1 研究背景 3