【作者】 郭建博；

【导师】 周集体； 王栋；

【作者基本信息】 大连理工大学 ， 环境工程， 2006， 博士

【摘要】 本研究通过对驯化、筛选耐盐菌的基础生物学研究和氧化还原介体加速偶氮染料厌氧生物降解技术,来解决高含盐染料废水中高盐对传统生物处理系统抑制现象和偶氮染料厌氧生物降解耗时长的问题。 由3种不同来源的污泥进行耐盐驯化得到3种耐盐菌群,耐盐程度达到250g L^-1NaCl,用其对高含盐染料K-2BP模拟废水的厌氧降解研究,具有高效的降解效果,同时进行了耐盐菌的降解广谱性实验,结果表明驯化耐盐菌群对所选取的13种不同结构的染料均有较高的降解效果,从而为常规生物法应用于高含盐废水的处理提供了实验基础和理论依据。 通过优势耐盐菌对偶氮染料K-2BP废水厌氧降解动力学实验,模拟得出高盐条件下,偶氮染料K-2BP和盐浓度对生物降解双重影响动力学模型。其抑制常数K_IS和K_T值分别为329.5±175.8 mg L^-1和39.7±27.1 g L^-1,说明耐盐菌受盐浓度和染料浓度的双重抑制。 针对偶氮染料厌氧生物降解耗时长的问题,进行了溴氨酸和固定化非水溶性蒽醌作为氧化还原介体对偶氮染料生物降解促进作用的研究,及4种固定化蒽醌技术的对比和溶解氧对降解过程的影响研究。结果表明溴氨酸和固定化蒽醌可提高偶氮染料生物厌氧降解速度率1.5-5倍,说明偶氮染料厌氧生物降解的氧化还原介体强化技术具备了理论上的可行性。 通过对4种结构相似偶氮染料的循环伏安特性测量及其生物厌氧降解速率实验,结果发现研究所选染料的生物降解速率分别为酸性黄-bis(Er-616.75 mV,0.01209 mol（g cell protein）^-1（h）^-1),酸性黄-11(Er-593.25 mV,0.01040 mol（g cellprotein）^-1（h）^-1),酸性黄-4(Er-513 mV,0.007575 mol（g cell protein）^-1（h）^-1),与各自循环伏安图中的还原峰电位间存在线性关系,Y=0.00004X-0.0116（R2=0.9424）,表明电化学方法有可能用于生物体系发生反应部分模拟和预测研究 通过氧化还原电位（ORP）的变化特征来研究降解过程,对比分析了15%（W/W）NaCl和15%（W/W）Na₂SO₄对氧化还原电位变化特征的影响;以及醌类化合物对染料降解和氧化还原电位变化特征的影响。结果推测和理论分析表明ORP下降到-93mV以下才可能发生偶氮染料厌氧降解,且降解过程中电位维持在较稳定区域（-200mV至-300mV）;不同盐类和醌类化合物（蒽醌和溴氨酸）对降解过程的氧化电位变化特征和降解有一定影响;而菌的浓度和染料浓度只对降解速度有影响,对ORP变化特征无影响。认为研究过程中ORP可作为偶氮染料生物厌氧降解过程中的一个重要控制参数。更多还原

【Abstract】 The purpose of this dissertation is to acclimate and isolate the salt-tolerant bacteria and investigate the accelerating effect of redox mediators in the bio-decolorization, which is used to solve the two possible bottlenecks of anaerobic-aerobic biotreatment of azo dyes: （1） high salinity of the dye wastewaters usually causes plasmolysis and/or loss of activity of cells, and some traditional aerobic- and anaerobic-biological treatments in low BOD removal performance;（2） anaerobic azo dye reduction is a time-consuming process, reflected by the requirement of long reaction times.Firstly, Three salt-tolerant mixed cultures （AS, SW, TAS） were acclimatized by the gradually increasing NaCl concentration and these acclimatized cultures could decolorize the 13 selected dyes with high salt concentration. The effects of salt concentration and dye concentration on decolorization rate were compared. With the elevated concentrations of salt and dye, the decolorization was lower. The abilities of decolorization by three mixed cultures were studied.Secondly, Degradation and inhibition kinetics of Reactive Brilliant Red K-2BP by salt-tolerant mixed culture were developed based on experimental results at different salt （NaCl） concentrations (5-150 g L^-1) and different dye concentrations (100-600 mg L^-1). The observed kinetic reaction coefficient was determined and correlated as a function of salt and dye concentration. The degradation rate follows first order kinetics with respect to dye concentration. Salt inhibition was expressed as a hyperbolic function. The values of K_T and K_IS were 39.784±27.169 g L^-1 and 329.524±175.822 mg L^-1, respectively.Then, The accelerating effect of redox mediators in the bio-decolorization was conducted. Decolorization of azo dyes was carried out experimentally using the salt-tolerant bacteria under redox mediators and high salt conditions. Anthnaquinone and bromoamine acid used as redox mediators were able to increase the decolorization rate of wastewater containing azo dyes. High decolorization rate was obtained in the presence of redox mediators at 30℃, which increased 1.5-5 fold, in comparison with the control of redox mediators. The experiments explored a great improvement of the redox mediator application and the new bio-treatment concept.Experiments were also conducted to study some electrochemical factors affecting the bacterial reduction （cleavage） of four azo dyes. And a common mixed culture was used as test organism and the reduction of azo dyes Acid Yellow 4, 11, 17 and Acid Yellow Bis was studied. It was found that the azo dyes were reduced at different rates, which could be correlated with the reduction potential of the azo compounds in cyclic voltammetric experiments. Acid Yellow bis （Er -616.75 mV） was reduced at the highest rate of 0.01209 mol （g cell protein）’1 （h）"1, Acid Yellow 11 （Er -593.25 mV） at 0.01040 mol （g cell protein）’1 （h）"1 and Acid Yellow 4 （Er -513 mV） at 0.007575 mol （g cell protein）"1 （h）"1. It was showed that the reduction potential would be a preliminary tool to predict the decolorization capacity of oxidative and reductive biocatalysts.Meanwhile, this work was conducted to study the change characteristics of the oxidation-reduction potentials （ORP） during the process of the biological decolorization of azo dyes, knowledge of which will be useful in the prediction of the decolorization capacity of oxidative and reductive biocatalysts. Reduction of these azo dyes did not occur under aeration conditions, and azo dyes were reduced by microorganisms only when the Oxidation-Reduction Potential （ORP） values decrease the certain limits （<-93 mV） during the decolrization processes. At the same time, sulfate salt, anthnaquinone （AQ） and 1-amino -4-bromo-2-anthraquinonesulfonic acid （BAA） were tested to assess the effects on the change of ORP during the decolorization process. These studies with the salt-tolerant mixed culture indicate that the reduction of azo dyes might be influenced by the chemical nature of the azo compound and redox mediatorsAt last, strain GTW and GTY were isolated and identified as Halomonas sp. and Gracilibacillus sp. based on morphological and physio-biochemical characteristics and 16S rDNA sequence analysis, and were deposited as patent strains in China General Microorganism Culture Center with the accession number CGMCC 1528 and CGMCC 1527, respectively. The 16S rDNA sequence of strain strain GTW and GTY were also submitted to GenBank with the number DQ 279849 and DQ 286727, respectively.更多还原