【作者】 陈刚；

【导师】 陈亮； Anna Kaksonen；

【作者基本信息】 东华大学 ， 环境科学与工程， 2012， 博士

【摘要】 活性黑5(reactive black5, RB5)是广泛应用于纺织行业的双偶氮染料,在生产和使用过程中产生的废水具有色度深、COD高、生物降解性能差的特点,对其废水的脱色显得很重要。此外,对氨基苯磺酸(sulfanilic acid, SA)是偶氮染料废水脱色后普遍存在的一种芳香胺类化合物。由于其含有磺酸基和氨基使其水溶性高、毒性大和结构稳定,已引起了健康和环境问题,所以在排入环境之前必须进行去除。本文利用从处理印染废水的活性污泥中筛选得到高效降解菌GY-1,考察了其对RB5脱色动力学特性。同时,研究了活性污泥对SA的降解性能及氨氧化细菌(Ammonium oxidizing bacteria, AOB)在SA降解中的作用,探讨了微生物燃料电池(microbial fuel cells,MFC)在处理含SA的酸性废水中的应用。本论文主要内容如下：1、从处理印染废水的污泥中分离得到一株可使双偶氮染料RB5很好脱色的菌株,初步鉴定该菌为肠杆菌并初步命名为GY-1；菌株GY-1的最佳生长条件为：蛋白胨为碳源、pH=10、温度为30℃、接种量为5%、装液量为50mL。2、肠杆菌GY-1对RB5脱色反应必须在厌氧条件下进行,最佳脱色条件为：温度为35℃,pH值为6,接种量为8mL,装液量为100mL。RB5脱色是由于菌株GY-1分泌的胞外诱导酶催化完成的。此外,菌株对其他19种染料脱色研究结果表明菌株GY-l具有广泛应用的可能性。3、菌株GY-1对RB5的脱色是通过微生物共代谢机理实现的,葡萄糖、淀粉、蔗糖、果糖、半乳糖、草酸和柠檬酸均可以作为RB5脱色的共代谢底物,葡萄糖作为共基质时,脱色效果较好,其最佳底物浓度为4g/L。有机氮(牛肉膏和蛋白胨)对RB5脱色具有促进作用而无机氮(硝酸钠)对RB5脱色具有明显的抑制作用。4、不同金属化合物对RB5脱色的影响不同：MnS04和MgS04可以促进菌株GY-1对RB5的脱色作用,而其它金属化合物对RB5脱色的活性有不同程度的抑制作用,顺序如下：Ag2SO4>CoSO4>Pb(NO3)2> HgSO4>CuSO4>FeCl3> ZnSO4>CaSO45、考察了在不同因素(初始染料浓度、温度、不同电子供体)下菌株GY-1对RB5的脱色动力学实验,并研究了菌株对不同染料脱色的动力学。通过阿伦尼乌斯方程得到了染料浓度、温度和菌体浓度之间的关系,1n(C1/C0)=1-n(Mk0)-Ea/RT,计算出RB5脱色反应的活化能(Ea)为8.5kcal mol-1,指前因子(A0)为6.28×107mg1gMLSS-1h-1,并通过Michaelis-Menten方程和Eadie-Hofstee曲线得到米氏常数(Km)为24.06mg1-1,最大反应速率(Vm)为1.05mg1-1·h-1。6、运用在线DO监测来分析系统中SA的好氧降解情况,通过定向驯化得到好氧降解SA的活性污泥,考察不同曝气量(0-1.74L/min)、溶解氧浓度(0-7mg/L)和初始SA浓度(104-1085mg/L)对SA生物降解的影响。采用修订的Haldane基质抑制模型模拟氧气消耗速率(Oxygen uptake rate, OUR)与初始SA浓度之间的关系。结果表明OUR与SA降解速率成正线性关系(R2≥0.91)。3.3mM SA完全降解后释放出3.2mM SO42-且COD的去除率高达97.1%,表明活性污泥作用下的SA几乎可以完全矿化。与单一菌种和混合菌种系统相比,降解SA的活性污泥中存在着氨氧化细菌(Ammonium-oxidizing bacteria, AOB),SA对AOB没有明显的抑制作用。7、考察了不同浓度的铵离子(NH4+)对SA降解的作用,分析了在丙烯基硫脲(Allylthiourea, ATU)的作用下选择性抑制污泥中的氨氧化细菌(Ammonium oxidizing bacteria, AOB)对SA降解及铵的氧化作用。结果表明,SA的比降解速率与起始铵离子的浓度呈负线性关系。在起始铵离子浓度很高的条件下(>10mM)活性污泥中的AOB对SA的降解具有促进作用。8、考察了连续进水低pH(pH=3)条件下MFC生物阴极系统对SA的降解作用,其结果表明MFC生物阴极系统对SA的降解具有促进作用。此外,研究了序批式条件下不同外阻时MFC生物阴极系统对SA降解的影响及不同曝气量下SA在MFC生物阴极系统中的降解作用。结果表明在初始溶液pH为7左右时低外阻条件下(1Ω和0.5Ω2)SA的降解速率小于高外阻时(100Ω)SA的降解速率。总之,本文选择RB5和SA作为典型的偶氮染料及芳香胺类化合物为研究对象,从处理印染废水污泥中分离出一株可以对RB5有效脱色的肠杆菌GY-1。系统研究了肠杆菌GY-1通过共代谢使RB5脱色,对其脱色特性及脱色动力学进行了深入的研究。此外,通过驯化得到有效降解SA的活性污泥,重点研究了氧气对活性污泥降解SA的影响,通过实时监测溶解氧浓度的变化来间接反映污水中SA的含量,研究了活性污泥中共生的氨氧化细菌在SA降解中的作用。此外探讨了利用MFC生物阴极来促进酸性条件下SA的降解。本研究为肠杆菌在偶氮染料废水处理中的应用提供了理论依据,并为传统活性污泥法处理偶氮染料脱色中间体提供了新的依据和实验基础以及电化学法在酸性废水处理中应用奠定了理论和实验基础。更多还原

【Abstract】 Reactive black5(RB5) which is widely used in textile industry is a typical disazo dye. Wastewater containing RB5should be treated before being discharged into environment as it has the features of deep color, high COD and poor biodegradability. Furthermore, sulfanilic acid is a common aromatic amine produced from decolorization of azo dyes. The negatively charged sulfonyl and amino groups of SA molecule are known to its high water solubility, high toxicity and structural stability. Due to environmental and health concerns, SA contained wastewaters need to be treated prior to its discharged into the environment.An Enterobacter strain (GY-1) was isolated from textile wastewater treating sludge. The kinetic of decolorization of RB5was studied. Whilst aerobic degradation of sulfanilic acid (SA) using activated sludge and the effect of ammonium-oxidizing bacteria on SA were investigated. Furthermore, degradation of SA using microbial fuel cells (MFC) was conducted. The main contents of this study are as follows.1、An Enterobacter strain (GY-1) with high activity of decolorization of Reactive Black5(RB5) was isolated from textile wastewater treating sludge. The optimal growth conditions are pH10, temperature30℃, inoculum5%and liquid volume50mL.2、Decolorization of RB5must be controlled under anaerobic condition. The optimal decolorizing conditions were35C, pH6, inoculum8mL and liquid volume100mL. The decolorization of RB5was attributed to extracellular enzymes. In addition, the strain GY-1exhibited widely decolorization as indicated by19kinds of dye decolorized by the strain GY-1.3、The mechanism in which bacteria GY-1decolorize RB5is cometabolism. Cometabolic substrate can be glucose, starch, sucrose, fructose, galactose, oxalic acid and citric acid, among which glucose is the best substrate of this study and the optimal concentration of substrate is4g/L. Organic compounds such as beef extract and peptone can facilitate decolorization of RB5, while inorganic compounds such as sodium nitrate had inhibitory effect on decolorization of RB5.4、Various metal compounds have different effects on activity of decolorization of RB5. MgSO4and MnSO4can increase the activity of decolorization of RB5. While some other compounds have inhibitory effects on the activity of decolorization of RB5. The sequence of the inhibitory effect of metal compounds on RB5decolorization is as follows: Ag2SO4> COSO4> Pb(NO3)2> HgSO4> CuSO4> FeCl3> ZnSO4> CaSO45、Effects of different operation parameters (temperature and dye concentration) and various electron donors/co-substrates on decolorization of RB5by GY-1were systematically investigated to reveal the key factors that determine the performance of the azo dye decolorization. A kinetic model was established giving the dependence of decolorization rate on cell mass concentration (first-order). The rate increased with increasing temperature from20to35℃, which can be predicted by Arrhenius equation with the activation energy (Ea) of8.50kcal mol-1and the frequency factor of6.28×107mg1g-MLSS-1h-1. Michaelis-Menten kinetics and Eadie-Hofstee plot were used to determine Vmax,1.05mg l-1h-1and Km,24.06mg l-16、Aerobic SA biodegradation could be monitored by real-time DO measurement. The sludge was enriched for over three months with SA (>500mg/L) as the sole carbon and energy source and dissolved oxygen (DO,>5mg/L) as the primary electron acceptor. Effects of aeration rate (0-1.74L/min), DO concentration (0-7mg/L) and initial SA concentration (104-1085mg/L) on SA biodegradation were quantified. A modified Haldane substrate inhibition model was used to obtain kinetic parameters of SA biodegradation and oxygen uptake rate (OUR). Positive linear correlations were obtained between OUR and SA degradation rate (R2>0.91). The concomitant release of near stoichiometric quantity of sulphate (3.2mmole SO42-released from3.3mmole SA) and the high chemical oxygen demand (COD) removal efficacy (97.1%) indicated that the enriched microbial consortia could drive the overall SA oxidation close to a complete mineralization. In contrast to other pure-culture systems, the ammonium released from the SA oxidation was predominately converted into nitrate, revealing the presence of ammonium-oxidizing bacteria (AOB) in the mixed culture. No apparent inhibitory effect of SA on the AOB activity (i.e. nitrification) was noted.7、A series of batch kinetic experiments were conducted to evaluate the effect of AOB on aerobic SA degradation in a SA-enriched activated sludge culture capable of oxidizing SA and ammonium simultaneously. To account for the effect of AOB on SA degradation, allylthiourea (ATU) was used to suppress AOB activity in the culture. The results indicated that specific SA degradation rate of the mixed culture was negatively correlated with the initial ammonium concentration (0-93mM-N, R2=0.99). The presence of AOB could accelerate SA degradation by reducing the inhibitory effect of ammonium (>10mM-N).8、Effects of biocathode of MFC on degradation of SA with pH3by continuous experiments were studied. The result indicated that the biocathode of MFC could facilitate degradation of SA. Furthermore, the effects of external resistance and aeration rate on degradation of SA and characteristics of biocathode were also investigated. SA degradation rate with low external resistance (0.5Ω and1Ω) was higher than that with high external resistance (100Ω). Overall, RB5and SA which are tipical azo dye and aromatic aimine, separately were studied in this work. The strain GY-1with high efficient decolorization of RB5was isolated from activated sludge treating dye wastewater. Decolorization of RB5by GY-1through cometabolism was investigated systimaticaly. Decolorizing characterization and kinetic were further investigated. Furthermore, activated sludge with ability of degrading SA efficiently was obtained by acclimatizing using SA as the sole carbon and energy source. The effect of dissolve oxygen (DO) on decolorization of SA by activated sludge was studied. The concentration of SA could be indicated indirectly through in-stu DO measurement. In addition, on the use of MFC to facilitate biocathodic degradation of SA under acidic condition was also carried out. This study not only provided theoretical basis for treatment of wastewater containing azo dyes,but also estabilised foundation and experimental basis for mineralization of products from decolorization of azo dyes and treatment of acidic wastewater using electrochemical method.更多还原