- I - 摘要 江苏某化工企业的水杨酸生产废水，是典型的高盐、含酚且难生物降解的 强酸性有毒有机工业废水，其 pH 值为 2、含盐量高达 2.5%、含酚高、B/C 仅 为 0.07，不适宜采用常规的生物法处理，而物理法的处理成本又很高，因此采 用化学氧化法中的 Fenton 法来处理该废水。针对传统 Fenton 工艺中存在的产泥 量大的问题，本课题通过对纳米 Fe 3 O 4 颗粒的制备和表面改性，提出一种基于 新型磁纳米催化剂的 Fe 3 O 4 -H 2 O 2 类 Fenton 体系。通过探讨该类 Fenton 体系对 水杨酸生产废水的处理效能，优化工艺的运行参数，为该废水提出一种可行的 处理方法。 首先采用化学共沉淀法合成纳米 Fe 3 O 4 ，用四甲基氢氧化铵（TMAH）和 2,3-二巯基丁二酸（DMSA）对其进行表面改性，共合成 5 种催化剂，分别为， 1#Fe 3 O 4 、2#Fe 3 O 4 -TMAH（1mL）、3#Fe 3 O 4 -TMAH（2mL）、4#Fe 3 O 4 -DMSA 和 5#Fe 3 O 4 -TMAH-DMSA。纳米颗粒的平均粒径约为 30 nm，并在 20~80 nm 的 范围内呈现良好的粒度分布，改性后的纳米 Fe 3 O 4 表面有甲基、巯基、羧基包 覆，颗粒的分散性提高。 之后就纳米 Fe 3 O 4 -H 2 O 2 类 Fenton 体系对 50 mg/L 的苯酚模拟废水的处理效 果进行探讨。12±2℃时，催化剂投量为 0.8 mmol/L、H 2 O 2 浓度为 2.0 mmol/L、 pH 为 4.5、反应 180 min 后，COD 去除率最高可达 72%，挥发酚去除率接近 100%。 在催化剂稳定性方面，3#和 5#的回用性最好，1#的回用性最差。与传统 Fenton 法相比，该类 Fenton 体系在降低铁泥产量方面有较好的改善，反应结束后，磁 纳米 Fe 3 O 4 在外磁场作用下可快速分离回收，并且催化剂可以重复利用。 最后探讨该类 Fenton 体系对水杨酸生产废水的处理效能，并优化反应器的 工艺运行参数。15±2℃时，催化剂投量为 2.0 mmol/L、H 2 O 2 浓度为 7.0 mmol/L、 pH 为 5.0、反应 120 min 后，水杨酸生产废水的处理效果达到最佳，出水 COD 值为 34~42 mg/L，挥发酚值为 0.21~0.43 mg/L；3#和 5#的催化效果最好，2#和 1#次之，4#催化效果相对最差。使用 TMAH 和 DMSA 对纳米 Fe 3 O 4 进行表面改 性能提高催化剂的稳定性，综合考虑认为 5#催化剂为最佳。20±2℃时，调节进 水 pH 为 5.0、停留时间 60 min，将 H 2 O 2 混合在进水中连续投加且浓度在 7.0 mmol/L 附近，5#催化剂维持在 1.0~2.0 mmol/L，连续运行反应器后，出水 COD 值在 40~50 mg/L 左右，挥发酚值在 0.2 mg/L 附近波动，色度为 2~4 倍，调节 pH 后能稳定达标排放。 应用纳米 Fe 3 O 4 -H 2 O 2 类 Fenton 体系处理实际的工业废水，并且连续运行反 应器使催化剂循环使用，是本报告的创新之处。该类 Fenton 体系一定程度上改 善了传统 Fenton 法在铁泥产生量方面的不足。本课题的研究为该企业的水杨酸摘要 - II - 生产废水提出一种可行的处理方法，同时为纳米 Fe 3 O 4 -H 2 O 2 类 Fenton 体系实现 工程化应用提供了理论基础和指导意见。 关键词，磁纳米 Fe 3 O 4 ；类 Fenton 体系；水杨酸生产废水；高盐废水；低 B/C 废水Abstract - III - Abstract The salicylic acid production wastewater which comes from a chemical company in Jiangsu Province is a typical acidic saliferous phenolic toxic organic industrial wastewater. Its pH value is 2, salt content is as high as 2.5% and with high phenols, but the B/C is only 0.07, so the conventional biological treatment is not suitable for this wastewater. Besides, the cost of physical method is very high, we choose Fenton method which is a kind of chemical oxidation method to treat this wastewater. In view the problem of large amount of sludge production of the traditional Fenton method, this topic put forward a Fe 3 O 4 -H 2 O 2 Fenton-like system based on a new type of magnetic nanosopic catalyst by Fe 3 O 4 nanoparticles preparation and surface modification. This study optimized the process operation parameters by means of discussing the salicylic acid production wastewater efficiency by this Fenton-like system, and proposed a feasible method for the wastewater. First of all, Fe 3 O 4 magnetic nanoparticles were prepared using chemical co-precipitation, and the surface was modified with tetramethyl ammonium hydroxide (TMAH) and meso-2,3-dimercaptosuccinic acid (DMSA), synthesizing five kinds of catalysts, which were named 1#Fe 3 O 4 , 2#Fe 3 O 4 -TMAH(1mL), 3#Fe 3 O 4 -TMAH(2mL), 4#Fe 3 O 4 -DMSA and 5#Fe 3 O 4 -TMAH-DMSA respectively. The results showed that the mean size of the Fe 3 O 4 nanoparticles was around 30 nm and they showed a good disparity between 20 and 80 nm. The Fe 3 O 4 nanoparticles were coated by methyl, sulfydryl and carboxyl after surface modification, which leaded to better dispersing performance of the nanoparticles. Secondly, the catalyzed degradation of phenol by Fe 3 O 4 -H 2 O 2 Fenton-like system was investigated in this study. Under the condition of 12±2℃, 0.8 mmol/L catalyst dosage, 2.0 mmol/L H 2 O 2 dosage, pH 4.5 and the reaction time of 180 minutes, the highest COD removal efficiency was 72%, the removal rate of volatile phenol was close to 100%. 3# and 5# catalysts revealed optimal reuse efficiency, 1# was the worst. This Fenton-like system had an advantage in the amount of iron sludge producing compared with traditional Fenton method. The magnetic catalyst was able to realize quick separation and recycling under the action of outside magnetic field, and the catalysts can be reused. Finally, the treatment efficiency of salicylic acid production wastewater by Fe 3 O 4 -H 2 O 2 Fenton-like system was investigated in this study, and the process operation parameters were optimized. Under the condition of 15±2℃, 2.0 mmol/L catalyst dosage, 7.0 mmol/L H 2 O 2 dosage, pH 5.0 and the reaction time of 120 minutes, salicylic acid production wastewater treatment got the best results that effluent COD value was between 34 and 42 mg/L, volatile phenol value wasAbstract - IV - between 0.21 and 0.43 mg/L, the catalytic effect of 3# and 5# were best, 2# and 1# followed by, 4# was the worst relatively. The stability of the nano Fe 3 O 4 catalysts can be improved by surface modification using TMAH and DMSA, 5# catalyst was considered the optimal. Under the condition of 20±2℃, pH 5.0, residence time 60 min, 7.0 mmol/L H 2 O 2 dosage mixed in the influent, 5# catalyst 1.0~2.0 mmol/L, operatied the reactor continuously, the effluent COD value was between 40 to 50 mg/L, volatile phenol value fluctuated near 0.2 mg/L, the chroma was between 2 to 4 times, the effluent was able to meet the emissions standards steadily after adjusting the pH. The innovations of this thesis are the application of nano Fe 3 O 4 -H 2 O 2 Fenton-like system in actual industrial wastewater treatment and continuous operation of the reactor by catalyst recycling. This Fenton-like system has improved the insufficient of high iron sludge producing problem of traditional Fenton system. This study has proposed a feasible method for the salicylic acid production wastewater treatment, meanwhile, this study has provided theoretical basis and guidances for the practical industrial application of nano Fe 3 O 4 -H 2 O 2 Fenton-like system. Keywords: Fe 3 O 4 magnetic nanoparticles; Fenton-like system; salicylic acid production wastewater; high salinity wastewater; low B/C wastewater目 录 - V - 目 录 摘要 ..........................................................................................................................I Abstract......................................................................................................................III 目 录 ........................................................................................................................V 第 1 章 绪 论 ...........................................................................................................1 1.1 课题背景及研究的目的和意义....................................................................... 1 1.2 水杨酸生产废水的处理现状........................................................................... 1 1.2.1 水杨酸及其生产工艺................................................................................ 1 1.2.2 水杨酸生产废水水质及现有处理方法.................................................... 1 1.3 Fenton 技术研究现状 ....................................................................................... 3 1.3.1 Fenton 技术简介 ........................................................................................ 3 1.3.2 Fenton 技术的研究热点 ............................................................................ 3 1.3.3 Fenton 技术目前存在的问题 .................................................................... 4 1.4 纳米 Fe 3 O 4 材料的制备 ...................................................................................4 1.4.1 化学共沉淀法............................................................................................ 4 1.4.2 微乳液法.................................................................................................... 5 1.4.3 水热法......................................................................................................... 6 1.4.4 高温有机液相回流法................................................................................. 7 1.5 磁纳米 Fe 3 O 4 -H 2 O 2 类 Fenton 体系研究现状 .................................................7 1.5.1 未经修饰的纳米 Fe 3 O 4 类 Fenton 体系研究 ............................................7 1.5.2 超声或表面修饰后的纳米 Fe 3 O 4 类 Fenton 体系研究 ...........................8 1. 6 本文的主要研究内容 ..................................................................................... 9 第 2 章 实验材料与方法 .........................................................................................10 2.1 实验试剂及仪器............................................................................................. 10 2.1.1 实验废水来源及性质、目标污染物的确定.......................................... 10 2.1.2 实验药品.................................................................................................. 11 2.1.3 实验仪器.................................................................................................. 11 2.2 实验操作 ........................................................................................................ 11 2.2.1 磁纳米 Fe 3 O 4 -Fenton 反应降解苯酚...................................................... 11 2.2.2 磁纳米 Fe 3 O 4 -Fenton 反应处理水杨酸生产废水.................................. 12 2.3 分析测试方法 ................................................................................................ 13 2.3.1 磁纳米颗粒的表征方法.......................................................................... 13 2.3.2 各项水质指标的检测方法...................................................................... 13目 录 - VI - 第 3 章 磁纳米 Fe 3 O 4 的合成及特性表征 ..............................................................15 3.1 引言 ................................................................................................................ 15 3.2 磁纳米 Fe 3 O 4 的制备及表面改性 .................................................................15 3.2.1 纳米 Fe 3 O 4 制备 ......................................................................................15 3.2.2 纳米 Fe 3 O 4 的表面改性 ..........................................................................16 3.3 纳米颗粒的特性表征..................................................................................... 16 3.3.1 催化剂的粒度分布.................................................................................. 16 3.3.2 催化剂晶体参数...................................................................................... 18 3.3.3 催化剂 FTIR 表征 ................................................................................... 18 3.4 本章小结 ........................................................................................................ 20 第 4 章 磁纳米 Fe 3 O 4 -Fenton 体系降解苯酚 ......................................................... 21 4.1 引言 ................................................................................................................ 21 4.2 磁纳米 Fe 3 O 4 -Fenton 体系降解苯酚最佳参数确定...................................... 21 4.2.1 催化剂投量的影响.................................................................................. 21 4.2.2 双氧水浓度的影响.................................................................................. 23 4.2.3 pH 的影响................................................................................................. 26 4.2.4 反应时间的影响...................................................................................... 27 4.2.5 温度的影响.............................................................................................. 29 4.3 催化剂降解苯酚的稳定性考察...................................................................... 31 4.4 本章小结 ........................................................................................................ 33 第 5 章 磁纳米 Fe 3 O 4 -Fenton 体系处理水杨酸生产废水 ..................................... 34 5.1 引言 ................................................................................................................ 34 5.2 磁纳米 Fe 3 O 4 -Fenton 体系处理水杨酸生产废水最佳参数确定.................. 34 5.2.1 催化剂投量的影响.................................................................................. 34 5.2.2 双氧水浓度的影响.................................................................................. 36 5.2.3 pH 的影响................................................................................................. 38 5.2.4 温度的影响.............................................................................................. 41 5.3 催化剂处理水杨酸生产废水的稳定性考察................................................. 42 5.4 水质 GC-MS 分析 .......................................................................................... 45 5.4.1 水杨酸生产废水的典型污染物解析...................................................... 45 5.4.2 总离子图分析.......................................................................................... 47 5.5 反应器最佳运行参数确定............................................................................. 47 5.5.1 停留时间的影响...................................................................................... 47 5.5.2 投药方式的影响...................................................................................... 49目 录 - VII - 5.6 本章小结 ........................................................................................................ 50 结 论 .......................................................................................................................52