廊道推流式生物电化学系统还原偶氮染料效能和机制研究

发布时间：2017-12-28 08:52

本文关键词：廊道推流式生物电化学系统还原偶氮染料效能和机制研究　出处：《哈尔滨工业大学》2017年博士论文　论文类型：学位论文

【摘要】：偶氮染料是分子结构中含有一个或多个偶氮键(-N=N-)的芳香类化合物,是目前工业中应用最多的合成染料,具有结构稳定、抗酸碱、抗微生物等特点,被大量使用,尤其是印染等产业。偶氮染料表现出极高的色度,在自然界中极难降解及代谢产物高毒性和致癌性的特点,含有偶氮染料的废水对生态系统和人类健康造成严重威胁。中国印染产业规模巨大,产生的工业废水中含有大量的偶氮染料,我国现在对于相关废水的处理主要针对废水的脱色脱毒来进行处理。传统的物理和化学处理方法,成本高且容易产生有毒有害的中间产物。厌氧生物处理可以对偶氮染料进行有效脱色,然而厌氧生物处理所需时间过长,导致脱色效率较低,且废水中缺乏可直接利用的电子供体,成为生物处理偶氮染料类废水的制约性因素。生物电化学系统(Bioelectrochemical Systems,BESs),以微生物为催化剂在电极进行氧化/还原反应,结合了生物处理和电化学方法的优点,已成为近年来发展迅速、很有前景的环境污染处理技术。本研究选取茜素黄R(Alizarin Yellow R,茜素黄R),一种最普遍应用的偶氮染料为模式污染物,针对传统的双极室生物电化学系统成本高、且难以工程放大,开发设计了一种廊道推流式连续流生物电化学反应器(Plug Flow Baffled-Bioelectrochmical Reactor,PFB-BER),围绕高脱色效能和低电能耗,优化了反应器的设计运行参数;结合阴极生物膜微生物群落结构组成,解析了连续流情况下PFB-BER的长期脱色效能和与好氧曝气(Aeration Reactor)系统联合(PFB-BER-AR)后的长期矿化效能。以反应器构型改进为目的,建立了一种廊道推流式生物电化学反应器,在连续流条件下可以实现对茜素黄R的快速还原脱色,脱色效率较开路情况下提高了1.27倍(水力停留时间为24h时),对苯二胺和5-氨基水杨酸生成率分别为95%和50%。循环伏安曲线和交流阻抗分析表明,系统外加电压控制在0.5V,使阴极电位控制在-0.9 V左右,可以保证茜素黄R的还原反应的发生,充分还原降解。反应器的总内阻为121.1Ω,远小于纯电化学反应器的内阻。随着反应器水力停留时间的缩短,反应器的还原脱色效率降低。当水力停留时间从8 h缩短到4 h时,还原脱色效率从69.9%降低到44.9%。增加一组电极组可以明显提高脱色效率,4 h的脱色效率由44.8%升高到83.1%。对比外加电压能耗,发现在相对一致的还原脱色效率下,水力停留时间为4 h的两组电极反应装置,要比水力停留时间为12 h的一组电极反应装置能耗低。适当增加电极组,可有效提高脱色效率并避免高的电压能耗。在生物电化学反应器阴极系统中,茜素黄R可以被快速还原脱色(乙酸钠:0.1818±0.0139/h;葡萄糖:0.4620±0.0567/h),其还原脱色效率较非生物阴极(0.0.1197±0.0004/h)分别提高了1.5倍(乙酸钠)和3.9倍(葡萄糖)。其出水色度符合国家二级出水标准色度要求(40)。不同参数条件下,茜素黄R的还原脱色速率随初始浓度的增加而降低,随外加电压的升高而升高;以葡萄糖为底物,茜素黄R的去除速率及产物的生成速率是以乙酸钠为底物条件的3倍。基于响应曲面模型拟合,得出茜素黄R初始浓度为130-135 mg/L和155 mg/L和外加电压为0.66 V和0.58 V(分别以乙酸钠和葡萄糖为基质)时,生物阴极的脱色效率最高,且单位能耗最低。生物阴极生物膜群落结构分析表明,驯化后细菌群落结构发生很大变化,以葡萄糖为底物时,Citrobacter、Enterococcus和Alkaliflexus等菌属为主导菌属,以乙酸钠为底物时,Acintobacter和Achromobacter等为主导菌属。底物不同导致群落结构差异和不同的还原脱色效率,表明以葡萄糖作为电子供体时能驯化出有利于茜素黄R还原脱色的菌群,提高反应器的性能。廊道推流式生物电化学反应器在长期运行的情况下,可以持续稳定地脱色茜素黄R。将此反应器与好氧曝气装置联合,其还原产物(对苯二胺和5-氨基水杨酸)可进一步被氧化,实现茜素黄R的长期持续矿化。微生物群落结构分析表明,长期运行情况下,电极类型和电极位置明显影响了电极生物膜上菌群的丰度和菌属类型。阳极生物膜以Ornatilinea菌属为主导,阴极生物膜以Acinetobacter,Pseudomonas和Geobacter为主导,Geobacter菌属在第二组电极组上的含量远高于第一组电极组。推断生物膜结构的变化受水中污染物浓度影响较大。本研究证实生物电化学系统可作为还原脱色偶氮染料的有效手段,开发设计的廊道推流式反应器可作为一种新型工艺处理模式,为染料类废水的脱色和彻底脱毒及系统工艺放大提供一种新的技术手段。
[Abstract]:Azo dyes are aromatic compounds containing one or more azobenzene bonds (-N=N-) in the molecular structure. They are the most widely used synthetic dyes in the industry. They are characterized by stable structure, acid and alkali resistance and microbial resistance. They are widely used, especially in printing and dyeing industries. Azo dyes show very high chromaticity. They are extremely difficult to degrade in nature and the characteristics of high toxicity and carcinogenicity of metabolites. Wastewater containing azo dyes poses a serious threat to ecosystem and human health. The scale of China's printing and dyeing industry is huge. Industrial wastewater contains a lot of azo dyes. Now, the treatment of related wastewater is mainly aimed at the decolorization and detoxification of wastewater. Traditional physical and chemical treatment methods have high cost and easy to produce toxic and harmful intermediate products. Anaerobic biotreatment can effectively decolorization azo dyes. However, the time needed for anaerobic biotreatment is too long, resulting in low decolorization efficiency, and the lack of directly used electronic donors in waste water has become a restrictive factor for biological treatment of azo dye wastewater. Bioelectrochemical Systems (BESs) has been used as an oxidant / reductive electrode at the electrode, combined with the advantages of biological treatment and electrochemical methods. It has become a promising and promising environmental pollution treatment technology in recent years. This study selected the Alizarin Yellow R (Alizarin Yellow R, Alizarin Yellow R), one of the most common applications of azo dyes as model pollutant, the cost of double chamber bioelectrochemical system of traditional high, and difficult to scale-up, design a corridor push flow type continuous bio electrochemical reactor (Plug Flow Baffled-Bioelectrochmical Reactor, PFB-BER), around the high decolorization efficiency and low electric power consumption, design and operation parameters of the reactor were optimized; combined with the microbial community structure of the cathode biofilm composition, analysis of the long-term continuous decolorization efficiency in case of PFB-BER and aeration and aerobic (Aeration Reactor) system (PFB-BER-AR) combined with long-term efficacy after mineralization. In order to improve the reactor configuration for the purpose of establishing a corridor push flow bio electrochemical reactor under continuous flow can achieve rapid decolorization of Alizarin Yellow R, decolorization efficiency is increased by 1.27 times under the condition of open circuit (HRT 24h), two of benzene amine and 5- amino salicylic acid generation rates were 95% and 50%. Cyclic voltammetry and AC impedance analysis indicate that the external voltage of the system is controlled at 0.5V, so that the cathodic potential is controlled at about -0.9 V, which can guarantee the reduction reaction of Alizarin Yellow R, and fully degrade and degrade. The total internal resistance of the reactor is 121.1 Omega, which is far less than the internal resistance of the pure electrochemical reactor. With the shortening of the hydraulic retention time of the reactor, the reduction and decolorization efficiency of the reactor decreased. When the hydraulic retention time is shortened from 8 h to 4 h, the reduction decolorization efficiency is reduced from 69.9% to 44.9%. The decolorization efficiency of a group of electrodes increased significantly, and the decolorization efficiency of 4 h increased from 44.8% to 83.1%. Compared with the external voltage consumption, it was found that under the relatively uniform reduction and decolorization efficiency, the two group of electrode reaction devices with hydraulic retention time of 4 h had lower energy consumption than a set of electrode reaction devices with a hydraulic retention time of 12 h. The appropriate increase of the electrode group can effectively improve the decolorization efficiency and avoid high voltage energy consumption. In the bio electrochemical reactor cathode system, Alizarin Yellow R can be rapid decolorization (acetate: 0.1818 + 0.0139/h; glucose: 0.4620 + 0.0567/h), the decolorization efficiency is non bio cathode (0.0.1197 + 0.0004/h) were increased 1.5 times and 3.9 times (acetate) (glucose). Its water color accords with the national standard of two grade effluent standard (40). Under different parameters, the reduction decolorization rate of Alizarin Yellow R decreased with the increase of initial concentration, and increased with the increase of applied voltage. On the basis of glucose, the removal rate of Alizarin Yellow R and product formation rate were 3 times higher than that of sodium acetate. Based on the fitting of the response surface model, it is concluded that the initial concentration of Alizarin Yellow R is 130-135 mg/L and 155 mg/L, and the applied voltage is 0.66 V and 0.58 V, respectively. When the sodium acetate and glucose are used as matrix respectively, the decolorization efficiency of the biological cathode is the highest and the unit energy consumption is the lowest. Analysis shows that the bio cathode biofilm community structure, domesticated bacterial community structure changed, with glucose as substrate, Citrobacter, Enterococcus and Alkaliflexus belongs to the genus of dominant species, with sodium acetate as substrate, Acintobacter and Achromobacter led to sp.. Different substrates lead to differences in community structure and different reductive decolorization efficiency. It indicates that when glucose is used as electron donor, bacteria can help to reduce the decolorization of Alizarin Yellow R, and improve the performance of the reactor. The Alizarin Yellow R can be continuously decolored in the long-term operation of the porch push-flow bioreactor. When the reactor is combined with aerobic aeration device, its reducing products (benzene two amine and 5- amino salicylic acid) can be further oxidized to achieve long-term continuous mineralization of Alizarin Yellow R. The analysis of microbial community structure showed that the type of electrode and the position of electrode significantly affected the abundance of bacteria and the type of bacteria on the electrode biofilm in the long run. The anodic biofilms were dominated by Ornatilinea bacteria, and the cathodic biofilms were dominated by Acinetobacter, Pseudomonas and Geobacter. The content of Geobacter bacteria on the second sets of electrode groups was much higher than that of the first set of electrode groups. It is inferred that the changes in the structure of the biofilm are greatly influenced by the concentration of pollutants in the water. This study demonstrated that bio electrochemical system can be used as effective means of decolorization of azo dyes, development and design of the corridor plug flow reactor can be used as a new treatment mode, for the decolorization of dye wastewater and thorough process of removing poison and system provides a new technical means to enlarge.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：X703

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